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Oracle - SQL - Not Null Constraint
 
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Oracle - SQL - Not Null Constraint Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Anadi Sharma, Tutorials Point India Private Limited.
Oracle SQL Tutorial 19 - ON DELETE (SET NULL and CASCADE)
 
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Welcome everyone! Something you need to consider when you are creating foreign keys is what happens if you delete the parent? As a reminder, the parent is the row that has the value you are referencing in the row that has a foreign key. Why is this something important to consider? It's important because foreign keys need to protect us from two primary things, unacceptable INSERT statements, and unacceptable DELETE statements. Let's see what happens when we try to insert incorrect data into the table with the foreign key: INSERT INTO projects VALUES (1, 'Update website homepage', 'CalebCurry') The response tells us plainly that there is no such user in the users table. So this works correctly. Deleting data on the other hand works a bit differently because the database does not know what you want to do with the child row when you delete the parent from the parent table. By default, we will get an error message that prevents the parent from being deleted, but there are some other options. How do we configure this? This is where the ON DELETE statement comes in. We add the keywords ON DELETE right after the foreign key and then we can give it the option of CASCADE or SET NULL. CASCADE means that if we delete the parent, we are also going to delete the child. In our situation what that means is that if somebody creates a project in our project table and then that persons account gets deleted, all of the projects he owns will also be deleted. CASCADE: CREATE TABLE projects( project_id NUMBER, Project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL, CONSTRAINT projects_pk PRIMARY KEY (project_id), CONSTRAINT projects_users_fk FOREIGN KEY (creator) REFERENCES users (username) ON DELETE CASCADE ) SET NULL will take the value in the child table and get rid of it. What you are left with is NULL. This means that we have an orphaned child. The first thought you might have is that it is a bad thing to have an orphaned child, but in databases that is not always so. In our application if we had it set to SET NULL, when a user account gets deleted the projects would remain in existence they would just lack a creator. This might be a good thing if you are concerned about the long term survival of a project, this might be the route you want to go. It ultimately depends on the application purpose. If you don't like CASCADE or SET NULL, you can leave the entire ON DELETE statement and just have Oracle throw an error when a parent is deleted. As for us, we are going to use ON DELETE CASCADE. We need to use this with extreme caution. If you are not careful, someday you will run a delete a row and that will cascade through you database deleting a bunch of stuff you didn't want to delete. Stuff happens, so make sure you back up your database every once in eternity. Now, in the last video we started with a database design that had three tables. We've only created two in this video. In the next video we are going to create the next one, which is a little special. Then we'll finish things up by adding some indexes. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me on Patreon! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 15119 Caleb Curry
Which Order Should Columns Go in an Index?: Finding All the Red Sweets Part 4
 
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When you create an index on multiple columns there's an important question you need to answer: In which order should you list the columns? This video looks at some of the factors you should consider to help answer this question. ============================ The Magic of SQL with Chris Saxon Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Views: 4053 The Magic of SQL
Null Values in Attributes | Database Management System
 
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This lecture explains about Null Values in attributes. To ask your doubts on this topic and much more, click on this Direct Link: http://www.techtud.com/video-lecture/lecture-21 IMPORTANT LINKS: 1) Official Website: http://www.techtud.com/ 2) Virtual GATE(for 'All India Test Series for GATE-2016'): http://virtualgate.in/login/index.php Both of the above mentioned platforms are COMPLETELY FREE, so feel free to Explore, Learn, Practice & Share! Our Social Media Links: Facebook Page: https://www.facebook.com/techtuduniversity Facebook Group: https://www.facebook.com/groups/virtualgate/ Google+ Page: https://plus.google.com/+techtud/posts Last but not the least, SUBSCRIBE our YouTube channel to stay updated about our regularly uploaded new videos.
Views: 17916 Techtud
Oracle interview question difference between null functions
 
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Difference between NVL,NVL2, NULLIF and COALESCE NVL function will check whether the first input parameter is null, if first input parameter is null then the function returns the second parameter value as output. NVL2 function will check the first parameter, and return second parameter if the first parameter is not null, otherwise returns third parameter. NULLIF will compare the input parameters ( first and second parameter ), and returns NULL of both are same, otherwise returns the first parameter value. COALESCE, returns the first not null expression in the given input parameters. -------------------------------------------------------------------------------------------------------- List of all the SQL and PLSQL interview questions https://easy-learning-tech.blogspot.com/p/oracle-sql-plsql-interview-questions.html
Views: 235 Siva Academy
oracle interview question oracle index function based index
 
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Title: Oracle Interview Question - oracle index related questions - Function based index in oracle Description: Oracle Interview Question - oracle index related questions 1. What is Index? How to create index? 2. What are the types of index? 3. How to find the list of indexes for a given table? 4. Explain B-tree index 5. Explain Bitmap index 6. Explain "Function based" index 7. Explain "Reverse Key" index 8. When to choose what type of index? 9. How to know index is being used? 10. How to monitor index usage? 11. What are the advantages/drawbacks of indexes?
Views: 127 Siva Academy
Oracle Sql Step by Step Approach (041 how are null values treated while sorting data)
 
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Oracle Sql Step by Step Approach (041 how are null values treated while sorting data) Discover essential SQL skills necessary to transform you into SQL developer which can earn you $70k+ in the IT Industry Learn to become a fee-earning SQL developer in just seven weeks. This fast, easy and effective course will take you from zero sql writing skills to being able to make money as a SQL developer. This one-stop-shot-style SQL course will teach you everything you need to know about SQL, from learning various database concepts to writing SQL to interact with the database. Throughout this SQL course I will be using the below methodology to make you think and help in forming the SQL statement. Like,Comment,Share
Oracle Training - Oracle SQL Training | How to Create Oracle SLQ Outer Joins and Self Joins
 
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This Oracle SQL training from https://www.fireboxtraining.com/oracle demonstrates how to perform inner joins, outer joins, and self joins to access data from more that one Oracle table where the join conditions contain NULL values.
Views: 4130 Firebox Training
Oracle SQL Tutorial 12 - Intro to Constraints
 
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As I believe I've mentioned in an earlier video, a constraint is basically a rule we can put in our database that prevents someone from putting the wrong data in. It protects our relationships and data integrity. Because the goal of these constraints are to protect our data integrity, you may hear them called integrity constraints. There are many integrity constraints we are going to talk about: NOT NULL UNIQUE PRIMARY KEY FOREIGN KRY CHECK There is also the DEFAULT attribute. These are all keywords we can add to our columns that will change the way the database works with our data and also prevents incorrect data. NOT NULL is a constraint you can put on a column that prevents nulls. A null is the absence of a value. When we say null, we are saying that every single row has to have a value for this column. UNIQUE is a constraint that makes every row have a unique value for this column. Now note, this does not require values to be put it, and it will allow multiple rows to be null. Next, we are going to talk about primary keys. What qualifies a column as a candidate key? First, not a single row should have a null for that column. Second, every row must be unique. The primary key constraint is essentially a combination of the NOT NULL constraint and the UNIQUE constraint. The foreign key constraint sets the requirement that any value in this column for any row must match a row in another column. Check constraints allow us to be more strict with what data is allowed in our database. NOT NULL and UNIQUE give some level of restriction, but what if we want something more specific? For example, what if we only want values between 0 and 100? That is where check constraints come in. When using check constraints, you give a boolean expression. A boolean expression is something that can be evaluated to true or false. It will only insert the row if the value you try to put into the row makes the expression evaluate to true. So if you put in a value too great or small, the expression will be false and the data is not allowed to be entered. The default constraint is a value you can give a column, and if for any reason when the row is created in the table a value is not provided, the default value will be given. So for example, we could have a bank account table where the balance defaults to 0. How do you actually implement these constraints when you are creating a table? In the next video we are going to be adding these to our users table. Please be sure to subscribe! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me on Patreon: http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 19927 Caleb Curry
SQL Constraints - NOT NULL , UNIQUE , PRIMARY KEY , FOREIGN KEY , CHECK , INDEX , default
 
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SQL is a standard Structured query language for storing, manipulating and retrieving data in databases. NOT NULL , UNIQUE , PRIMARY KEY , FOREIGN KEY , CHECK , INDEX , default 1) NOT NULL - Ensures that a column cannot have a NULL value 2) UNIQUE - Ensures that all values in a column are different 3) PRIMARY KEY - A combination of a NOT NULL and UNIQUE. Uniquely identifies each row in a table 4) FOREIGN KEY - Uniquely identifies a row/record in another table. The table containing the foreign key is called the child table, and the table containing the candidate key is called the referenced or parent table. prevents invalid data and destroy links between tables. 5) CHECK - Ensures that all values in a column satisfies a specific condition 6) DEFAULT - Sets a default value for a column when no value is specified 7) INDEX - Used to create and retrieve data from the database very quickly.
Views: 20 R K
17/125 Oracle PLSQL: Handling Nulls in IF Statement
 
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Learn Oracle PLSQL EXAM 1Z0-144
Views: 1114 khaled alkhudari
Important concepts on NULL values
 
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Join Discussion:http://www.techtud.com/video-lecture/important-concepts-null-values IMPORTANT LINKS: 1) Official Website: http://www.techtud.com/ 2) Virtual GATE: http://virtualgate.in/login/index.php Both of the above mentioned platforms are COMPLETELY FREE, so feel free to Explore, Learn, Practice & Share! Our Social Media Links: Facebook Page: https://www.facebook.com/techtuduniversity Facebook Group: https://www.facebook.com/groups/virtualgate Google+ Page: https://plus.google.com/+techtud/posts Last but not the least, SUBSCRIBE our YouTube channel to stay updated about the regularly uploaded new videos.
Views: 4139 Techtud
DBMS - Null Values in SQL
 
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DBMS - Null Values in SQL Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Arnab Chakraborty, Tutorials Point India Private Limited
SQL tutorial 72: NVL SQL NULL function By Manish Sharma RebellionRider
 
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Part 1: SQL Null Function NVL learn the concepts of NVL null function in this tutorial with examples and all the Interview concepts covered ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog : http://bit.ly/nvl-sql-null-function Previous Tutorial ► LPAD & RPAD Functions https://youtu.be/nPtbuHPCN6E ------------------------------------------------------------------------- ►►►Let's Get Free Uber Cab◄◄◄ Use Referral Code UberRebellionRider and get $20 free for your first ride. ------------------------------------------------------------------------- ►►►Help Me In Getting A Job◄◄◄ ►Help Me In Getting A Good Job By Connecting With Me on My LinkedIn and Endorsing My Skills. All My Contact Info is Down Below. You Can Also Refer Me To Your Company Thanks ------------------------------------------------------------------------- Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=kb4rc1 -------------------------------------------------------------------------- ►Make sure you SUBSCRIBE and be the 1st one to see my videos! -------------------------------------------------------------------------- Amazon Wishlist: http://bit.ly/wishlist-amazon ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ►►►Find me on Social Media◄◄◄ Follow What I am up to as it happens on https://twitter.com/rebellionrider https://www.facebook.com/imthebhardwaj http://instagram.com/rebellionrider https://plus.google.com/+Rebellionrider http://in.linkedin.com/in/mannbhardwaj/ http://rebellionrider.tumblr.com/ http://www.pinterest.com/rebellionrider/ You can also Email me at for E-mail address please check About section Please please LIKE and SHARE my videos it makes me happy. Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com ♥ I LOVE ALL MY VIEWERS AND SUBSCRIBERS
Views: 24765 Manish Sharma
Tutorial 44 : NULL in Oracle || NVL() Explained
 
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Hi Friends! Here we are learning about what is NULL in Oracle. How we can deal with NULL Values. How NVL() Function helps us with NULL Value. Hope the concept and example would be clear to you. For any help or issue, let me know in comment box. Thanks, Happy Coding.
Views: 76 YourSmartCode
NULL-Related Functions in Oracle
 
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An overview of some of the functions Oracle provides to handle NULL values in SQL and PL/SQL. For more information see: https://oracle-base.com/articles/misc/null-related-functions Website: https://oracle-base.com Blog: https://oracle-base.com/blog Twitter: https://twitter.com/oraclebase Cameo by Bjoern Rost Blog: http://portrix-systems.de/blog/brost/ Twitter: https://twitter.com/brost Cameo appearances are for fun, not an endorsement of the content of this video.
Views: 2630 ORACLE-BASE.com
SQL TUTORIALS : NULL VALUES
 
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WHAT IS NULL IN SQL PLUS? DEFINING NULL VALUE.
Views: 2642 learnoracle9i
Oracle SQL Tutorial 20 - How to Create Composite Primary Keys
 
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This video is going to be a tutorial on how to create composite and compound keys. The difference between a composite and compound key is that a composite key can consist of any columns while a compound key has to consist of columns that are all keys themselves. We will be working with a compound key because we are going to be using the an intermediary table that has two foreign keys. The combination of both of the keys have to be unique. First, if we have any other CREATE TABLE commands, we are going to comment those out. We will space out the CREATE TABLE to have each column on a line, then we will add constraints as needed. CREATE TABLE project_users( project_id, user_id ) Now, let's add the data types: CREATE TABLE project_users( project_id NUMBER, user_id NUMBER } Now, what about some column attributes? I'm going to make both of the columns NOT NULL because we always want the rows to have a user and a project: CREATE TABLE project_users( project_id NUMBER NOT NULL, user_id NUMBER NOT NULL } Now, let's add the foreign key constraints. Now, what do we name these? We are going to add a primary key that covers both of these columns, so I'm going to be a sinner and not give these constraints names: CREATE TABLE project_users( project_id NUMBER NOT NULL REFERENCES projects (project_id), user_id NUMBER NOT NULL REFFERENCES users (user_id) ) Now, the way we have it now is that if we delete a project in the project table, and there are any rows in the project_users table, it will throw an error and prevent deletion. I would prefer for it to also delete any project members. That would make sense because if you delete a project we want it to delete the associate between that project and certain users. The same goes for if we delete a user, we want their association with a certain project to be deleted. To do this, we need to add the ON DELETE command: CREATE TABLE project_users( project_id NUMBER NOT NULL REFERENCES projects (project_id) ON DELETE CASCADE, user_id NUMBER NOT NULL REFERENCES users (user_id) ON DELETE CASCADE, ) Finally, let's learn how to create a compound or composite key. literally, the only difference is that you put a comma and add the second table inside of the parenthesis. CREATE TABLE project_users( project_id NUMBER NOT NULL REFERENCES projects (project_id) ON DELETE CASCADE, user_id NUMBER NOT NULL REFERENCES users (user_id) ON DELETE CASCADE, CONSTRAINT project_users_pk PRIMARY KEY (project_id, user_id) ) Now, the combination of project_id and user_id cannot be null, is always unique, and has an index. The only thing we should do now is add a few indexes. We aren't done yet...In the next video we are going to figure out what columns would benefit from indexes and we'll add them to it. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELP ME! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 10491 Caleb Curry
Efficient Function Calls From SQL (Part 6) : Function-Based Indexes
 
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The sixth part of a mini-series of videos showing how you can improve the performance of function calls from SQL. In this episode, we look at using function-based indexes to improve the performance of queries that use function calls in the WHERE clause. For more information see: https://oracle-base.com/articles/8i/function-based-indexes https://oracle-base.com/articles/misc/efficient-function-calls-from-sql#functions-in-the-where-clause Website: https://oracle-base.com Blog: https://oracle-base.com/blog Twitter: https://twitter.com/oraclebase Cameo by Ronald Bradford : Blog: http://ronaldbradford.com/blog/ Twitter: https://twitter.com/RonaldBradford Cameo appearances are for fun, not an endorsement of the content of this video.
Views: 1424 ORACLE-BASE.com
Null: Databases for Developers #10
 
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The null value represents missing or unknown information. But using it brings complications to your SQL. In this video Chris discusses how to work with null to ensure you get the correct results. Further reading: Oracle Database SQL Reference on Nulls: http://docs.oracle.com/database/122/SQLRF/Nulls.htm#SQLRF30037 Null related functions: http://docs.oracle.com/database/122/SQLRF/Single-Row-Functions.htm#SQLRF51187 Is null condition: http://docs.oracle.com/database/122/SQLRF/Null-Conditions.htm#SQLRF52152 Need help with SQL? Ask us over on AskTOM: https://asktom.oracle.com Twitter: https://twitter.com/ChrisRSaxon Daily SQL Twitter tips: https://twitter.com/SQLDaily All Things SQL blog: https://blogs.oracle.com/sql/ ============================ The Magic of SQL with Chris Saxon Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Views: 2797 The Magic of SQL
Validation Rule: Is Not Null
 
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Validation Rule: Is Not Null
Views: 7692 Perins Elearning
Differences between primary key and unique key - SQL Server Interview Questions
 
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Hi Friends, In this in this session we are going to learn the differences between primary key and unique key This is one of the most frequently asked sql server interview questions. Before we discuss the difference between primary key and unique key, let's see what a primary key is and what a unique key is. Primary Key: Primary key is a key which uniquely identifies each row/record in the table. This implies if you have a primary key on a table, you can identify each and every row in that table uniquely using primary key. Unique Key: Unique key constraint enforces the uniqueness on the columns in which it is defined. That is Unique key will make sure only unique values are allowed in the columns in which it is defined. Similarities: Both Primary key and unique Key enforces uniqueness on the columns on which they are defined. • Primary key and unique Key columns allow only unique values. • Primary key and unique Key columns will avoid duplicates • Both Primary key and unique Key columns uniquely identifies each row/record in the table Differences: PRIMARY KEY UNIQUE KEY Primary Key Does not allow duplicates Unique key allows only one NULL A table can have only 1 Primary Key A table can have multiple Unique Keys By default Primary Key creates a Unique Clustered Index on the table By default Unique Key creates a Unique Non-Clustered Index on the table. I hope this session is clear and i hope this knowldge should help you in interviews. Please share your valuable comments & sugesstions. Also, subscriber to my channel for more sql server interview questions and answers. Bye bye & Have a good day.
Views: 39017 TheSSScreations
SQL Null or Empty   How to Check for Null or Empty Column in SQL Server   SQL Training Online
 
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http://www.sqltrainingonline.com SQL Null or Empty - How to Check for Null or Empty Column in SQL Server - SQL Training Online You can download the sample table script at http://www.sqltrainingonline.com/how-to-filter-for-sql-null-or-empty-string/. In this video, I show you how to filter for a SQL null or empty string. It can be difficult to filter a null because you can't simply compare with an equal sign. You have to use a special IS NULL clause to make the filter work. I also show you how to combine both the SQL Null and Empty String together in a special trick with the isnull SQL Server function. I use SQL Server 2012 to demonstrate the technique. Let me know what you think by commenting or sharing on twitter, facebook, google+, etc. If you enjoy the video, please give it a like, comment, or subscribe to my channel. You can visit me at any of the following: SQL Training Online: http://www.sqltrainingonline.com Twitter: http://www.twitter.com/sql_by_joey Google+: https://plus.google.com/#100925239624117719658/posts LinkedIn: http://www.linkedin.com/in/joeyblue Facebook: http://www.facebook.com/sqltrainingonline
Views: 16947 Joey Blue
26. IS NULL and IS NOT NULL in SQL (Hindi)
 
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Please Subscribe Channel Like, Share and Comment Visit : www.geekyshows.com
Views: 19431 Geeky Shows
Oracle DENSE_RANK Function
 
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https://www.databasestar.com/oracle-dense_rank/ The Oracle DENSE_RANK function allows you to calculate a rank of a row in a group of rows. It returns this rank as a NUMBER value. This function can be used as either an analytic or an aggregate function, and the syntax depends on how you use it. As an aggregate function it looks like this: DENSE_RANK ( expr, [expr(n)] ) WITHIN GROUP ( ORDER BY (order_expr [ASC|DESC] [NULLS FIRST|LAST] ) These parameters are: - expr: this is the value to search for in a particular table. You can specify multiple search values, and just separate them by a comma. - order_expr: this is used to order the expr values by, because you get a different results depending on what order you rank the values in. - NULLS FIRST or LAST: this is where you can specify if you want to have NULL values appear at the top of your ranking order or at the bottom. As an analytic function, it looks like this: DENSE_RANK() OVER ( [query_partition_clause] order_by_clause) The parameters are: - query_partition_clause: this is the expression that the ranking is “grouped” by, as analytic functions allow you to group data within rows. - order_by_clause: this is the expression to order your results by to determine a rank. For this function, if two records have the same sort or rank position, they will have the same RANK value. It won’t cause a gap in the rankings, unlike the RANK function which does cause a gap. For more information about the Oracle DENSE_RANK function, including all of the SQL shown in this video and the examples, read the related article here: https://www.databasestar.com/oracle-dense_rank/
Views: 310 Database Star
MySQL for Beginners 006: Null Values and Not Null
 
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This is a free section of a full course to get you started with MySQL. Full course: http://courses.caveofprogramming.com/courses/mysql-and-sql-for-beginners MySQL allows columns to take "null" (not specified) values by default, so we'd better take a look ...
Views: 2954 Cave of Programming
Oracle COUNT Function
 
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https://www.databasestar.com/oracle-count/ The Oracle COUNT function is used to count the number of rows from the column, or number of values, provided to it. It’s commonly used to find the number of rows returned by a SELECT query. The syntax of the COUNT function is: COUNT ( [ * | [ DISTINCT | ALL ] expression) [ over (analytic_clause) ] There’s a lot of square brackets here, indicating optional parameters and choices. This just means you can use the COUNT function in a few different ways: COUNT(*) COUNT(DISTINCT expression) COUNT(ALL expression) COUNT(*) OVER (analytic_clause) COUNT(DISTINCT expression) OVER (analytic_clause) COUNT(ALL expression) OVER (analytic_clause) It can be used as an aggregate or analytic function. The parameters of the COUNT function are: - expression: The expression to count the values of. This can be a column or a set of values, for example. - analytic_clause: This is used to specify the criteria for an analytic query. COUNT(*) is the most common way to use this function, I’ve found. As COUNT(*) is an aggregate function, like all aggregate functions the columns mentioned in the SELECT clause need to exist in the GROUP BY clause. NULL values are ignored by COUNT(expression), but they are counted when using COUNT(*). COUNT(*) has the exact same calculation and performance as COUNT(1). For more information about the Oracle COUNT function, including all of the SQL shown in this video and the examples, read the related article here: https://www.databasestar.com/oracle-count/
Views: 172 Database Star
Unique and Non Unique Indexes in sql server   Part 37
 
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In this video we will learn about 1. What is a Unique Index 2. Difference between unique index and unique constraint Text version of the video http://csharp-video-tutorials.blogspot.com/2012/09/unique-and-non-unique-indexes-part-37.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-37-unique-non-unique-indexes.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 205256 kudvenkat
PL/SQL:NVL/NVL2/Coalesce function
 
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In this tutorial, you'll learn the difference between NVL,NVL2 &Coalesce functions PL/SQL (Procedural Language/Structured Query Language) is Oracle Corporation's procedural extension for SQL and the Oracle relational database. PL/SQL is available in Oracle Database (since version 7), TimesTen in-memory database (since version 11.2.1), and IBM DB2 (since version 9.7).[1] Oracle Corporation usually extends PL/SQL functionality with each successive release of the Oracle Database. PL/SQL includes procedural language elements such as conditions and loops. It allows declaration of constants and variables, procedures and functions, types and variables of those types, and triggers. It can handle exceptions (runtime errors). Arrays are supported involving the use of PL/SQL collections. Implementations from version 8 of Oracle Database onwards have included features associated with object-orientation. One can create PL/SQL units such as procedures, functions, packages, types, and triggers, which are stored in the database for reuse by applications that use any of the Oracle Database programmatic interfaces. PL/SQL works analogously to the embedded procedural languages associated with other relational databases. For example, Sybase ASE and Microsoft SQL Server have Transact-SQL, PostgreSQL has PL/pgSQL (which emulates PL/SQL to an extent), and IBM DB2 includes SQL Procedural Language,[2] which conforms to the ISO SQL’s SQL/PSM standard. The designers of PL/SQL modeled its syntax on that of Ada. Both Ada and PL/SQL have Pascal as a common ancestor, and so PL/SQL also resembles Pascal in several aspects. However, the structure of a PL/SQL package does not resemble the basic Object Pascal program structure as implemented by a Borland Delphi or Free Pascal unit. Programmers can define public and private global data-types, constants and static variables in a PL/SQL package.[3] PL/SQL also allows for the definition of classes and instantiating these as objects in PL/SQL code. This resembles usage in object-oriented programming languages like Object Pascal, C++ and Java. PL/SQL refers to a class as an "Abstract Data Type" (ADT) or "User Defined Type" (UDT), and defines it as an Oracle SQL data-type as opposed to a PL/SQL user-defined type, allowing its use in both the Oracle SQL Engine and the Oracle PL/SQL engine. The constructor and methods of an Abstract Data Type are written in PL/SQL. The resulting Abstract Data Type can operate as an object class in PL/SQL. Such objects can also persist as column values in Oracle database tables. PL/SQL is fundamentally distinct from Transact-SQL, despite superficial similarities. Porting code from one to the other usually involves non-trivial work, not only due to the differences in the feature sets of the two languages,[4] but also due to the very significant differences in the way Oracle and SQL Server deal with concurrency and locking. There are software tools available that claim to facilitate porting including Oracle Translation Scratch Editor,[5] CEITON MSSQL/Oracle Compiler [6] and SwisSQL.[7] The StepSqlite product is a PL/SQL compiler for the popular small database SQLite. PL/SQL Program Unit A PL/SQL program unit is one of the following: PL/SQL anonymous block, procedure, function, package specification, package body, trigger, type specification, type body, library. Program units are the PL/SQL source code that is compiled, developed and ultimately executed on the database. The basic unit of a PL/SQL source program is the block, which groups together related declarations and statements. A PL/SQL block is defined by the keywords DECLARE, BEGIN, EXCEPTION, and END. These keywords divide the block into a declarative part, an executable part, and an exception-handling part. The declaration section is optional and may be used to define and initialize constants and variables. If a variable is not initialized then it defaults to NULL value. The optional exception-handling part is used to handle run time errors. Only the executable part is required. A block can have a label. Package Packages are groups of conceptually linked functions, procedures, variables, PL/SQL table and record TYPE statements, constants, cursors etc. The use of packages promotes re-use of code. Packages are composed of the package specification and an optional package body. The specification is the interface to the application; it declares the types, variables, constants, exceptions, cursors, and subprograms available. The body fully defines cursors and subprograms, and so implements the specification. Two advantages of packages are: Modular approach, encapsulation/hiding of business logic, security, performance improvement, re-usability. They support object-oriented programming features like function overloading and encapsulation. Using package variables one can declare session level (scoped) variables, since variables declared in the package specification have a session scope.
Views: 4275 radhikaravikumar
Oracle Interview Question - oracle index related questions - BTREE index in oracle
 
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Oracle Interview Question - oracle index related questions 1. What is Index? How to create index? 2. What are the types of index? 3. How to find the list of indexes for a given table? 4. Explain B-tree index 5. Explain Bitmap index 6. Explain "Function based" index 7. Explain "Reverse Key" index 8. When to choose what type of index? 9. How to know index is being used? 10. How to monitor index usage? 11. What are the advantages/drawbacks of indes? List of all the SQL and PLSQL interview questions @ https://easy-learning-tech.blogspot.com/p/oracle-sql-plsql-interview-questions.html
Views: 186 Siva Academy
Oracle SQL Tutorial For Beginners | Oracle SQL Online Training - Session 1
 
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Course : Oracle SQL Online Training Mode of Training : Online Duration : 40 Hours Timings : Flexible Oracle SQL Online Training Demo Registration Link : http://svsoftsolutions.com/demo.aspx Introduction to SQL What is SQL? What Can SQL do? RDBMS SQL Syntax Database Tables SQL Statements Overview of Most Important SQL Commands SELECT UPDATE DELETE INSERT CREATE TABLE ALTER TABLE DROP TABLE CREATE INDEX DROP INDEX SQL SELECT Statement SELECT syntax Demo Database SELECT Column Example SELECT * Example SQL Distinct SELECT DISTINCT Statement SELECT DISTINCT Syntax SELECT DISTINCT Example SQL WHERE Clause WHERE Clause WHERE Clause Example Operators in the WHERE Clause SQL AND & OR Operators AND Operator Example OR Operator Example Combining AND & OR SQL ORDER BY ORDER BY Syntax ORDER BY Example ORDER BY DESC Example ORDER BY Several Column Examples SQL Insert Into INSERT INTO Syntax INSERT INTO Examples Insert Data into Specified Columns SQL UPDATE UPDATE Syntax UPDATE Example Watch out UPDATE statement. SQL DELETE DELETE Syntax DELETE Examples Delete All the Data SQL Aliases SQL Alias Syntax for Columns Alias Example for Table Columns Alias Example for Tables. SQL Joins Different SQL JOINs INNER JOIN LEFT OUTER JOIN RIGHT OUTER JOIN FULL OUTER JOIN SQL UNION UNION Syntax UNION Example UNION ALL Syntax UNION ALL Example SQL Insert Into Select INSERT INTO SELECT Syntax INSERT INTO SELECT Examples SQL Create Table CREATE TABLE Syntax CREATE TABLE Example SQL Constraints CREATE TABLE + CONSTRAINT Syntax NOT NULL Constraint UNIQUE Constraint UNIQUE Constraint on CREATE TABLE UNIQUE Constraint on ALTER TABLE To DROP a UNIQUE Constraint PRIMARY KEY Constraint PRIMARY KEY Constraint on CREATE TABLE PRIMARY KEY Constraint on ALTER TABLE To DROP a PRIMARY KEY Constraint FOREIGN KEY Constraint FOREIGN KEY Constraint on CREATE TABLE FOREIGN KEY Constraint on ALTER TABLE To DROP a FOREIGN KEY Constraint CHECK Constraint CHECK Constraint on CREATE TABLE CHECK Constraint on ALTER TABLE To DROP a CHECK Constraint DEFAULT Constraint on CREATE TABLE DEFAULT Constraint on ALTER TABLE To DROP a DEFAULT Constraint SQL Create Index CREATE INDEX Syntax CREATE UNIQUE INDEX Syntax CREATE INDEX Example SQL DROP Command The DROP INDEX Statement The DROP TABLE Statement The DROP DATABASE Statement The TRUNCATE TABLE Statement SQL ALTER Command The ALTER TABLE Statement ALTER TABLE Example Change Data Type Example DROP COLUMN Example SQL VIEWS CREATE VIEW Statement CREATE VIEW Syntax CREATE VIEW Examples CREATE OR REPLACE VIEW Syntax Dropping a View SQL NULL Values Working with NULL Values IS NULL IS NOT NULL SQL NULL Functions NVL COALESCE For more details visit our website : www.svsoftsolutions.com Or reach us @ USA : +1-845-915-8712 (Toll Free), India : +91-9642373173
Views: 1382 SV Soft Solutions
4- Oracle DB - Primary Foreign Unique Not Null Check Composite Keys Table Level and Column Level.avi
 
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Oracle DB - Primary Foreign Unique Not Null Check Composite Keys Table Level and Column Level
Views: 2681 Adel Sabour
Oracle NULLIF Function
 
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https://www.databasestar.com/oracle-nullif/ The Oracle NULLIF function is used to compare two values and determine if they match or not. If the two values match, NULLIF returns NULL. If they don’t match, the function returns the first value. The syntax of the NULLIF function is: NULLIF (expr1, expr2) These parameters are the two expressions to compare. As mentioned above, this function returns either: - NULL if expr1 and expr2 match - expr1 if expr1 and expr2 don't match Both of these parameters can be numeric, and they both need to be the same data type. The functionality of NULLIF can be written as a CASE statement. However, if a CASE statement is really what you need, then you should use that. NULLIF should only be used if that’s the functionality you require. For more information about the Oracle NULLIF function, including all of the SQL shown in this video and the examples, read the related article here: https://www.databasestar.com/oracle-nullif/
Views: 207 Database Star
Oracle SQL Tuning with NOT NULL Constraints
 
02:28
Learn how to tune SQL with Constraints! In this lesson (3 of 5), OCM John Watson from SkillBuilders demonstrates how to improve query performance by adding not null constraints. See all lessons, free at http://www.skillbuilders.com/oracle-database-sql-tuning-with-constraints.
Views: 395 SkillBuilders
SQL tutorial 62: Indexes In Oracle Database By Manish Sharma RebellionRider
 
04:03
Watch and learn concepts of SQL Index In Oracle Database. In this tutorial you will learn about B-Tree Index and Function based Index. ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog : Previous Tutorial ► ------------------------------------------------------------------------- ►►►Help Me In Getting A Job◄◄◄ ►Help Me In Getting A Good Job By Connecting With Me on My LinkedIn and Endorsing My Skills. All My Contact Info is Down Below. You Can Also Refer Me To Your Company Thanks ------------------------------------------------------------------------- Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=kb4rc1 -------------------------------------------------------------------------- ►Make sure you SUBSCRIBE and be the 1st one to see my videos! -------------------------------------------------------------------------- Amazon Wishlist: http://bit.ly/wishlist-amazon ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ►►►Find me on Social Media◄◄◄ Follow What I am up to as it happens on https://twitter.com/rebellionrider https://www.facebook.com/imthebhardwaj http://instagram.com/rebellionrider https://plus.google.com/+Rebellionrider http://in.linkedin.com/in/mannbhardwaj/ http://rebellionrider.tumblr.com/ http://www.pinterest.com/rebellionrider/ You can also Email me at for E-mail address please check About section Please please LIKE and SHARE my videos it makes me happy. Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com ♥ I LOVE ALL MY VIEWERS AND SUBSCRIBERS
Views: 40787 Manish Sharma
PL/SQL Tutorial | COALESCE Function in Oracle Database
 
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Learn fetching all non-null expression using oracle Coalesce function with example. If all expressions evaluate to null, then the COALESCE function will return null. Coalesce function in Oracle, What is coalesce function, When to use coalesce function, How to use coalesce function in oracle, How to fetch non-null values in oracle using coalesce, Linkedin: https://www.linkedin.com/in/aditya-kumar-roy-b3673368/ Facebook: https://www.facebook.com/SpecializeAutomation/
COALESCE Function in SQL ORACLE Query With Example
 
03:53
ORACLE/PLSQL: COALESCE FUNCTION The Oracle/PLSQL COALESCE function returns the first non-null expression in the list. If all expressions evaluate to null, then the COALESCE function will return null. The syntax for the Oracle/PLSQL COALESCE function is: coalesce( expr1, expr2, ... expr_n ) PARAMETERS: expr1 to expr_n are the expressions to test for non-null values. EXAMPLE: The COALESCE function can be used in Oracle/PLSQL. You could use the coalesce function in a SQL statement as follows: SELECT COALESCE( address1, address2, address3 ) result FROM suppliers; The above COALESCE function is equivalent to the following IF-THEN-ELSE statement: IF address1 is not null THEN result := address1; ELSIF address2 is not null THEN result := address2; ELSIF address3 is not null THEN result := address3; ELSE result := null; END IF; The COALESCE function will compare each value, one by one. Lets apply the same to emp table. We have some NULL values in comm and mgr columns. but not in any other columns. So lets take a example for this 2 columns. COALESCE(comm,mgr,sal) Here if comm is null, function returns mgr value. If mgr is null it returns sal value! Query used in video: SELECT ename,comm,mgr,sal,COALESCE(comm,mgr,sal) result FROM emp;
Views: 6299 WingsOfTechnology
Advantages and disadvantages of indexes in sql server   Part 38
 
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In this video we will learn about 1. Advantages and disadvantages of indexes 2. The types of queries that can benefit from indexes 3. Covering Queries Text version of the video http://csharp-video-tutorials.blogspot.com/2012/09/advantages-and-disadvantages-of-indexes.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-38-adv-dis-adv-of-indexes.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 158534 kudvenkat
Optional parameters in sql server stored procedures  Part 68
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2013/09/part-68-optional-parameters-in-sql.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-68-optional-parameters-in-sql_16.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists Parameters of a sql server stored procedure can be made optional by specifying default values. We wil be using table tblEmployee for this Demo. CREATE TABLE tblEmployee ( Id int IDENTITY PRIMARY KEY, Name nvarchar(50), Email nvarchar(50), Age int, Gender nvarchar(50), HireDate date, ) Insert into tblEmployee values ('Sara Nan','[email protected]',35,'Female','1999-04-04') Insert into tblEmployee values ('James Histo','[email protected]',33,'Male','2008-07-13') Insert into tblEmployee values ('Mary Jane','[email protected]',28,'Female','2005-11-11') Insert into tblEmployee values ('Paul Sensit','[email protected]',29,'Male','2007-10-23') Name, Email, Age and Gender parameters of spSearchEmployees stored procedure are optional. Notice that, we have set defaults for all the parameters, and in the "WHERE" clause we are checking if the respective parameter IS NULL. Create Proc spSearchEmployees @Name nvarchar(50) = NULL, @Email nvarchar(50) = NULL, @Age int = NULL, @Gender nvarchar(50) = NULL as Begin Select * from tblEmployee where (Name = @Name OR @Name IS NULL) AND (Email = @Email OR @Email IS NULL) AND (Age = @Age OR @Age IS NULL) AND (Gender = @Gender OR @Gender IS NULL) End Testing the stored procedure 1. Execute spSearchEmployees - This command will return all the rows 2. Execute spSearchEmployees @Gender = 'Male' - Retruns only Male employees 3. Execute spSearchEmployees @Gender = 'Male', @Age = 29 - Retruns Male employees whose age is 29
Views: 71594 kudvenkat
Constraint In Oracle PL SQL
 
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Constraint In Oracle PL SQL oracle tutorial for beginners A) UNIQUE CONSTRAINT : A unique constraint is uniquely defines a record. Its value is not repeated. It can be null. B)NOT NULL CONSTRAINT: Not null constraint restrict from inserting null values. If we want some columns does not take null values then we can use this constraint. C)CHECK CONSTRAINT: A check constraint allows you to specify a condition on particular column in a table. we can add our custom logical conditions. CREATE TABLE TEST2 ( ID VARCHAR2(10) UNIQUE, NAME VARCHAR2(50), DEPT VARCHAR2(10) NOT NULL, AGE NUMBER(10), CHECK (AGE BETWEEN 18 and 60) ); #techquerypond https://techquerypond.wordpress.com https://techquerypond.com https://twitter.com/techquerypond
Views: 181 Tech Query Pond
ORACLE Analytic Functions for Data Warehousing 2/ Arabic
 
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ORACLE Analytic Functions for Data Warehousing 2/ Arabic FIRST_VALUE last_VALUE row_number() --FIRST_VALUE and LAST_VALUE Analytic Functions select EMPLOYEE_ID, FIRST_NAME, HIRE_DATE from employees order by hire_date; select EMPLOYEE_ID, FIRST_NAME, HIRE_DATE , min(HIRE_DATE) over ( ) first_HIRE_DATE from employees select EMPLOYEE_ID, FIRST_NAME, HIRE_DATE , FIRST_VALUE(HIRE_DATE) over ( ) first_HIRE_DATE from employees order by hire_date; select EMPLOYEE_ID, FIRST_NAME, HIRE_DATE , max(HIRE_DATE ) over ( ) last_HIRE_DATE from employees select EMPLOYEE_ID, FIRST_NAME, HIRE_DATE , last_VALUE(HIRE_DATE ) over ( ) last_HIRE_DATE from employees order by HIRE_DATE drop table student_exam_result; CREATE TABLE student_exam_result (student_id number, exame_name varchar2(100), exame_try number, exame_results number ); insert into student_exam_result values(1,'calcluas',1,50); insert into student_exam_result values(1,'calcluas',2,66); insert into student_exam_result values(1,'calcluas',3,20); insert into student_exam_result values(2,'calcluas',1,66); insert into student_exam_result values(2,'calcluas',2,null); insert into student_exam_result values(2,'calcluas',3,7); insert into student_exam_result values(3,'calcluas',1,50); insert into student_exam_result values(3,'calcluas',2,98); insert into student_exam_result values(3,'calcluas',3,null); select * from student_exam_result select student_id, exame_name,exame_try,exame_results, last_value(exame_results) IGNORE NULLS over (PARTITION BY student_id, exame_name ) last_grade from student_exam_result order by student_id, exame_name, exame_try select student_id, exame_name,exame_try,exame_results, last_value(exame_results) IGNORE NULLS over (PARTITION BY student_id, exame_name ) last_grade, max(exame_results) over (PARTITION BY student_id, exame_name ) max_grade, avg(exame_results) over (PARTITION BY student_id, exame_name ) avg_grade from student_exam_result order by student_id, exame_name, exame_try ------------------------ select employee_id,first_name ,row_number() over(order by employee_id ) from employees select employee_id,first_name ,rownum from employees select employee_id,first_name ,department_id, row_number() over(partition by department_id order by employee_id ) from employees
Views: 625 khaled alkhudari
Synonyms in Oracle Database
 
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advantages of synonyms in oracle, how to find public synonyms in oracle, types of synonyms in oracle, oracle synonym table, create synonym oracle 11g, public and private synonyms in oracle, drop synonym oracle
Views: 51 Adam Tech
29 - SQL NULL Values - Learn SQL from www.SQLServerLog.com [HD]
 
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Description: This video is about SQL NULL Values in SQL Server [HD]. You can refer complete Text Tutorial on my website: www.SQLServerLog.com You can join me on social networks: Facebook: http://www.facebook.com/SQLServerLog Linkedin: http://in.linkedin.com/in/SQLServerLog Google+: http://www.google.com/+SQLServerLogs Twitter: http://www.twitter.com/SQLServerLog
Views: 263 SQLServer Log
Part 2   SQL query to get organization hierarchy
 
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Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2014/05/part-2-sql-query-to-get-organization.html To get the best out of this video, the following concepts need to be understood first. These are already discussed in SQL Server Tutorial. 1. Self-Join - http://www.youtube.com/watch?v=qnYSN_7qwgg 2. CTE - http://www.youtube.com/watch?v=ZXB5b-7HJHk 3. Recursive CTE - http://www.youtube.com/watch?v=GGoV0wTMCg0 Here is the problem definition: 1. Employees table contains the following columns a) EmployeeId, b) EmployeeName c) ManagerId 2. If an EmployeeId is passed, the query should list down the entire organization hierarchy i.e who is the manager of the EmployeeId passed and who is managers manager and so on till full hierarchy is listed. For example, Scenario 1: If we pass David's EmployeeId to the query, then it should display the organization hierarchy starting from David. Scenario 2: If we pass Lara's EmployeeId to the query, then it should display the organization hierarchy starting from Lara. We will be Employees table for this demo. SQL to create and populate Employees table with test data Create table Employees ( EmployeeID int primary key identity, EmployeeName nvarchar(50), ManagerID int foreign key references Employees(EmployeeID) ) GO Insert into Employees values ('John', NULL) Insert into Employees values ('Mark', NULL) Insert into Employees values ('Steve', NULL) Insert into Employees values ('Tom', NULL) Insert into Employees values ('Lara', NULL) Insert into Employees values ('Simon', NULL) Insert into Employees values ('David', NULL) Insert into Employees values ('Ben', NULL) Insert into Employees values ('Stacy', NULL) Insert into Employees values ('Sam', NULL) GO Update Employees Set ManagerID = 8 Where EmployeeName IN ('Mark', 'Steve', 'Lara') Update Employees Set ManagerID = 2 Where EmployeeName IN ('Stacy', 'Simon') Update Employees Set ManagerID = 3 Where EmployeeName IN ('Tom') Update Employees Set ManagerID = 5 Where EmployeeName IN ('John', 'Sam') Update Employees Set ManagerID = 4 Where EmployeeName IN ('David') GO Here is the SQL that does the job Declare @ID int ; Set @ID = 7; WITH EmployeeCTE AS ( Select EmployeeId, EmployeeName, ManagerID From Employees Where EmployeeId = @ID UNION ALL Select Employees.EmployeeId , Employees.EmployeeName, Employees.ManagerID From Employees JOIN EmployeeCTE ON Employees.EmployeeId = EmployeeCTE.ManagerID ) Select E1.EmployeeName, ISNULL(E2.EmployeeName, 'No Boss') as ManagerName From EmployeeCTE E1 LEFT Join EmployeeCTE E2 ON E1.ManagerID = E2.EmployeeId
Views: 278810 kudvenkat
PL/SQL: Collections Part-1
 
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In this tutorial, you'll learn the introduction to collections. PL/SQL (Procedural Language/Structured Query Language) is Oracle Corporation's procedural extension for SQL and the Oracle relational database. PL/SQL is available in Oracle Database (since version 7), TimesTen in-memory database (since version 11.2.1), and IBM DB2 (since version 9.7).[1] Oracle Corporation usually extends PL/SQL functionality with each successive release of the Oracle Database. PL/SQL includes procedural language elements such as conditions and loops. It allows declaration of constants and variables, procedures and functions, types and variables of those types, and triggers. It can handle exceptions (runtime errors). Arrays are supported involving the use of PL/SQL collections. Implementations from version 8 of Oracle Database onwards have included features associated with object-orientation. One can create PL/SQL units such as procedures, functions, packages, types, and triggers, which are stored in the database for reuse by applications that use any of the Oracle Database programmatic interfaces. PL/SQL works analogously to the embedded procedural languages associated with other relational databases. For example, Sybase ASE and Microsoft SQL Server have Transact-SQL, PostgreSQL has PL/pgSQL (which emulates PL/SQL to an extent), and IBM DB2 includes SQL Procedural Language,[2] which conforms to the ISO SQL’s SQL/PSM standard. The designers of PL/SQL modeled its syntax on that of Ada. Both Ada and PL/SQL have Pascal as a common ancestor, and so PL/SQL also resembles Pascal in several aspects. However, the structure of a PL/SQL package does not resemble the basic Object Pascal program structure as implemented by a Borland Delphi or Free Pascal unit. Programmers can define public and private global data-types, constants and static variables in a PL/SQL package.[3] PL/SQL also allows for the definition of classes and instantiating these as objects in PL/SQL code. This resembles usage in object-oriented programming languages like Object Pascal, C++ and Java. PL/SQL refers to a class as an "Abstract Data Type" (ADT) or "User Defined Type" (UDT), and defines it as an Oracle SQL data-type as opposed to a PL/SQL user-defined type, allowing its use in both the Oracle SQL Engine and the Oracle PL/SQL engine. The constructor and methods of an Abstract Data Type are written in PL/SQL. The resulting Abstract Data Type can operate as an object class in PL/SQL. Such objects can also persist as column values in Oracle database tables. PL/SQL is fundamentally distinct from Transact-SQL, despite superficial similarities. Porting code from one to the other usually involves non-trivial work, not only due to the differences in the feature sets of the two languages,[4] but also due to the very significant differences in the way Oracle and SQL Server deal with concurrency and locking. There are software tools available that claim to facilitate porting including Oracle Translation Scratch Editor,[5] CEITON MSSQL/Oracle Compiler [6] and SwisSQL.[7] The StepSqlite product is a PL/SQL compiler for the popular small database SQLite. PL/SQL Program Unit A PL/SQL program unit is one of the following: PL/SQL anonymous block, procedure, function, package specification, package body, trigger, type specification, type body, library. Program units are the PL/SQL source code that is compiled, developed and ultimately executed on the database. The basic unit of a PL/SQL source program is the block, which groups together related declarations and statements. A PL/SQL block is defined by the keywords DECLARE, BEGIN, EXCEPTION, and END. These keywords divide the block into a declarative part, an executable part, and an exception-handling part. The declaration section is optional and may be used to define and initialize constants and variables. If a variable is not initialized then it defaults to NULL value. The optional exception-handling part is used to handle run time errors. Only the executable part is required. A block can have a label. Package Packages are groups of conceptually linked functions, procedures, variables, PL/SQL table and record TYPE statements, constants, cursors etc. The use of packages promotes re-use of code. Packages are composed of the package specification and an optional package body. The specification is the interface to the application; it declares the types, variables, constants, exceptions, cursors, and subprograms available. The body fully defines cursors and subprograms, and so implements the specification. Two advantages of packages are: Modular approach, encapsulation/hiding of business logic, security, performance improvement, re-usability. They support object-oriented programming features like function overloading and encapsulation. Using package variables one can declare session level (scoped) variables, since variables declared in the package specification have a session scope.
Views: 14655 radhikaravikumar
Oracle - SQL - Insert Statement
 
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Oracle - SQL - Insert Statement Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Anadi Sharma, Tutorials Point India Private Limited.
Null values in SQL Server - Part 33
 
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Subscribe to IT PORT : https://www.youtube.com/c/itport28 SQL Server Tutorial in Tamil : https://www.youtube.com/playlist?list=PLouAaeZ4xQ64enJDwWVvN3KduuZRlUrb3 SQL Server Concepts in Tamil : https://www.youtube.com/playlist?list=PLouAaeZ4xQ67kdNIByJKAGBIBhor_h4Hs SQL Server Analytic Functions in Tamil : https://www.youtube.com/playlist?list=PLouAaeZ4xQ65XIU5azEUgLVrBKEl-jWMV SQL Server Tutorial : https://www.youtube.com/playlist?list=PLouAaeZ4xQ66AYrzPtxt2SeeR4UABcBcO SQL Server Concepts : https://www.youtube.com/playlist?list=PLouAaeZ4xQ66zRe8-nDDy-YHY2o0rmbn4 SQL Server Analytic Functions : https://www.youtube.com/playlist?list=PLouAaeZ4xQ64hTsEdhLsVBquE1vERWngX A column with a NULL value is a column with no value. If a column in a table is optional, it is possible to insert a new record or update a record without adding a value to this column. Then, the column will be saved with a NULL value.
Views: 70 IT Port
How to create Unique Constraint on Multiple Columns in SQL Server - SQL Server/TSQL Tutorial Part 96
 
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SQL Server / TSQL Tutorial Scenario: If you have noticed the insert statement, In First Record I have put both Null values for FirstName and Last Name. In 2nd record I used the value 'Aamir' for first name and Null for Last Name. In 3rd record vice versa of 2nd record. From here what we understand that the unique constraint is working on both column values. As long as the combined value from both columns is unique, it is going to let us insert even one of them is null. Link to scripts used in SQL Server / TSQL Tutorial Video http://www.techbrothersit.com/2016/05/how-to-create-unique-constraint-on.html Check out our website for Different SQL Server, MSBI tutorials and interview questions such as SQL Server Reporting Services(SSRS) Tutorial SQL Server Integration Services(SSIS) Tutorial SQL Server DBA Tutorial SQL Server / TSQL Tutorial ( Beginner to Advance) http://www.techbrothersit.com/
Views: 2268 TechBrothersIT
PL/SQL: Object Type
 
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In this tutorial, you'll learn what is a object type in sql/plsql PL/SQL (Procedural Language/Structured Query Language) is Oracle Corporation's procedural extension for SQL and the Oracle relational database. PL/SQL is available in Oracle Database (since version 7), TimesTen in-memory database (since version 11.2.1), and IBM DB2 (since version 9.7).[1] Oracle Corporation usually extends PL/SQL functionality with each successive release of the Oracle Database. PL/SQL includes procedural language elements such as conditions and loops. It allows declaration of constants and variables, procedures and functions, types and variables of those types, and triggers. It can handle exceptions (runtime errors). Arrays are supported involving the use of PL/SQL collections. Implementations from version 8 of Oracle Database onwards have included features associated with object-orientation. One can create PL/SQL units such as procedures, functions, packages, types, and triggers, which are stored in the database for reuse by applications that use any of the Oracle Database programmatic interfaces. PL/SQL works analogously to the embedded procedural languages associated with other relational databases. For example, Sybase ASE and Microsoft SQL Server have Transact-SQL, PostgreSQL has PL/pgSQL (which emulates PL/SQL to an extent), and IBM DB2 includes SQL Procedural Language,[2] which conforms to the ISO SQL’s SQL/PSM standard. The designers of PL/SQL modeled its syntax on that of Ada. Both Ada and PL/SQL have Pascal as a common ancestor, and so PL/SQL also resembles Pascal in several aspects. However, the structure of a PL/SQL package does not resemble the basic Object Pascal program structure as implemented by a Borland Delphi or Free Pascal unit. Programmers can define public and private global data-types, constants and static variables in a PL/SQL package.[3] PL/SQL also allows for the definition of classes and instantiating these as objects in PL/SQL code. This resembles usage in object-oriented programming languages like Object Pascal, C++ and Java. PL/SQL refers to a class as an "Abstract Data Type" (ADT) or "User Defined Type" (UDT), and defines it as an Oracle SQL data-type as opposed to a PL/SQL user-defined type, allowing its use in both the Oracle SQL Engine and the Oracle PL/SQL engine. The constructor and methods of an Abstract Data Type are written in PL/SQL. The resulting Abstract Data Type can operate as an object class in PL/SQL. Such objects can also persist as column values in Oracle database tables. PL/SQL is fundamentally distinct from Transact-SQL, despite superficial similarities. Porting code from one to the other usually involves non-trivial work, not only due to the differences in the feature sets of the two languages,[4] but also due to the very significant differences in the way Oracle and SQL Server deal with concurrency and locking. There are software tools available that claim to facilitate porting including Oracle Translation Scratch Editor,[5] CEITON MSSQL/Oracle Compiler [6] and SwisSQL.[7] The StepSqlite product is a PL/SQL compiler for the popular small database SQLite. PL/SQL Program Unit A PL/SQL program unit is one of the following: PL/SQL anonymous block, procedure, function, package specification, package body, trigger, type specification, type body, library. Program units are the PL/SQL source code that is compiled, developed and ultimately executed on the database. The basic unit of a PL/SQL source program is the block, which groups together related declarations and statements. A PL/SQL block is defined by the keywords DECLARE, BEGIN, EXCEPTION, and END. These keywords divide the block into a declarative part, an executable part, and an exception-handling part. The declaration section is optional and may be used to define and initialize constants and variables. If a variable is not initialized then it defaults to NULL value. The optional exception-handling part is used to handle run time errors. Only the executable part is required. A block can have a label. Package Packages are groups of conceptually linked functions, procedures, variables, PL/SQL table and record TYPE statements, constants, cursors etc. The use of packages promotes re-use of code. Packages are composed of the package specification and an optional package body. The specification is the interface to the application; it declares the types, variables, constants, exceptions, cursors, and subprograms available. The body fully defines cursors and subprograms, and so implements the specification. Two advantages of packages are: Modular approach, encapsulation/hiding of business logic, security, performance improvement, re-usability. They support object-oriented programming features like function overloading and encapsulation. Using package variables one can declare session level (scoped) variables, since variables declared in the package specification have a session scope.
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