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A case study on using Composite Unique Indexes in Oracle on nullable columns
 
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We use unique indexes in Oracle to maintain distinct values in columns. Let us explore a case where we have Unique Indexes on(combination of) two or more columns in a table in Oracle, where one column has mostly null values.
Views: 7 Peeush Trikha
Oracle SQL Tutorial 21 - How to Create / Drop Indexes
 
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In the last video, we wrote up the SQL to create three tables: CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) UNIQUE, CONSTRAINT users_pk PRIMARY KEY (user_id) ); 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 ); 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) ); I'm going to increase the size of the users table a bit by adding a first and last name column. CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) UNIQUE, first_name VARCHAR2(50 CHAR), last_name VARCHAR2 (50 CHAR), CONSTRAINT users_pk PRIMARY KEY (user_id) ); But before we finish this design, we should consider indexing certain columns. What columns should we index? Well, as a reminder, the columns that are indexed by default are columns with the UNIQUE constraint, and those that are labeled as primary keys. Columns that are not indexed but often should be are those labeled as a foreign key. The column that jumps out the most to me is the creator column of the project table. It's the only foreign key that is not part of some index. Let's fix this by creating our first index. The way we do that is with the CREATE INDEX command. CREATE INDEX projects_creator_ix ON projects (creator) What naming convention are we following for the index? We are naming it by the table name, followed by an underscore, followed by the column, followed by an underscore, followed by an ix (for index). In this situation it does not apply, but if our foreign key column is labeled as UNIQUE, we can add the UNIQUE keyword like this: CREATE UNIQUE INDEX projects_creator_ix ON projects (creator) Now if you want to get rid of an INDEX, you can use this command: DROP INDEX projects_creator_ix Now, if we want to select data from the user table and the project table we can do that much faster. That's because the foreign key and column it references are both indexed and those are the columns we would do the join on. We will discuss how to do joins in a future video. So what are some potential problems with this database design? Overall, it is pretty good. With this design though we need to make sure there is no way for someone to update a user's username. In the next video we are going to discuss why. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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: 10121 Caleb Curry
Oracle Unique Constraint تعليم اوراكل
 
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by Mohamed El Desouki - محمد الدسوقى [email protected] Tel :00966 553450836 جامعة سلمان بن عبد العزيز - السعودية - الخرج How To Add Unique Constraint to Table. Unique كيف تستخدم قيد الــ Text Book: Fundamentals of Database Systems, 5th Edition, by Elmasri/Navathe, published by Addison-W oracle create table statement oracle drop table statement oracle constraints database constraints primary key constraint foreign key constraint check constraint null not null constraint unique constraint
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.
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: 221327 kudvenkat
Working with Unique Not Null And check Constraints in SQL Server | MSSQL Training | By Mr.Sudhakar L
 
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Views: 5898 Naresh i Technologies
UNIQUE AND NON-UNIQUE INDEX IN SQL (URDU / HINDI)
 
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Views: 556 Learning Never Ends
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: 19057 Caleb Curry
SQL Server 26 - PRIMARY KEY, NOT NULL, UNIQUE
 
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In the last video we created our first table, but I want to give SQL Server some extra information so the database knows more about each of the columns. The first thing is to establish the primary key. To do this all we do is add PRIMARY KEY after the column we want to be the primary key. Simple enough. When we add a constraint right after the column like this, it is often called a column attribute. CREATE TABLE Animals( ID INT PRIMARY KEY, Name VARCHAR(50), Species VARCHAR(50) ); Additionally, if you are using an ID column, it is best to have it labeled as the IDENTITY column. That way, SQL Server will automatically increment the number. CREATE TABLE Animals( ID INT PRIMARY KEY IDENTITY, Name VARCHAR(50), Species VARCHAR(50) ); The other attributes we've discussed in this series are NOT NULL and UNIQUE. We can make the name NOT NULL and the species NOT NULL. We don't have a good column for UNIQUE, so let's add one: CREATE TABLE Animals( ID INT PRIMARY KEY IDENTITY, Name VARCHAR(50) NOT NULL, Species VARCHAR(50) NOT NULL, ContactEmail VARCHAR(50) NOT NULL UNIUQE ); You can see that it is very easy to add multiple column attributes to a column. Just separate them by spaces. The order does not matter. Also, when you say primary key the column is automatically NOT NULL and UNIQUE. There are other attributes you can use including DEFAULT, FOREIGN KEY, and SPARSE. DEFAULT will give a value for a column if you do not put anything in yourself. Foreign keys are used to reference other columns. SPARSE is an attribute we haven't discussed. You can use SPARSE if most of the rows are going to have a NULL for a column and it saves storage space, but we will worry about that in another video. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support 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: 6177 Caleb Curry
Common Oracle SQL Tuning Errors - Lesson 5: NULLS Tuning Issues
 
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Lesson 5: Learn about NULLs and a problem or two it can cause. All lessons are free at https://www.skillbuilders.com/free-oracle-database-tutorials/common-oracle-sql-tuning-errors/ Learn about our classes (online an on-premise). SQL Tuning for Beginners: https://www.skillbuilders.com/course/oracle-sql-tuning-core-skills-for-beginners/ SQL Tuning for Developers and DBAs: https://www.skillbuilders.com/course/oracle-12c-sql-tuning-for-developers-and-dbas/
Views: 125 SkillBuilders
NOT NULL, DEFAULT, CHECK Constraints (Domain Integrity) in SQL Server
 
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NOT NULL, DEFAULT, CHECK Constraints (Domain Integrity) in SQL Server Check my blog for more on Constraints and related sample SQL Queries: http://sqlwithmanoj.com/2010/11/23/integrity-constraints/ Check the whole "SQL Server Basics" series here: https://www.youtube.com/playlist?list=PLU9JMEzjCv14f3cWDhubPaddxRvx1reKR Check my SQL blog at: http://sqlwithmanoj.com/ Check my SQL FB Page at: https://www.facebook.com/sqlwithmanoj
Views: 16693 SQL with Manoj
Oracle Interview question How To Get unique records without using distinct in oracle
 
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Oracle Interview question How To Get unique records without using distinct in oracle? http://easy-learning-tech.blogspot.com/2018/07/how-to-get-unique-records-without-using.html List of all the SQL and PLSQL interview questions @ https://easy-learning-tech.blogspot.com/p/oracle-sql-plsql-interview-questions.html
Views: 1700 Siva Academy
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: 198 Tech Query Pond
Oracle Database Indexes: Myths, Tips and Tricks
 
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In this tutorial, OCM John Watson will - via demonstrations - debunk these myths: Myth #1: Oracle Database does not index NULL Myth #2: A search that includes wildcards can't use an index if the wildcard precedes the string. Myth #3: Oracle will not use a function-based index unless the FBI is coded in the predicate. Myth #4: Indexes always help. The more indexes the better. See http://skillbuilders.com/free-oracle-tutorials for gigabytes of free Oracle video tutorials.
Views: 16450 SkillBuilders
Understanding Primary Key, Unique and Null Constraints
 
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In this video discusses Null, Unique and Primary Key constraints of SQL. It also covers demonstration of these constraints in Oracle.
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: 26837 Manish Sharma
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: 2008 Siva Academy
UNIQUE KEY CONSTRAINT IN ORACLE SQL WITH EXAMPLE
 
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This is a free video tutorial by Kishan mashru on unique constraint in Oracle SQL, the video firstly explains what unique constraint is and how it can be used along with its various limitations, then the video gives perfect examples to understand how to create a unique key at the column level or inline, or at the table level i.e out of line. The video gives a demonstration on ALTER TABLE ADD CONSTRAINT and ALTER TABLE DROP CONSTRAINT statements also.
Views: 1189 Kishan Mashru
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 12C Tutorial 20 - Constraints (Primary, Foreign, Unique, Null etc.)
 
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This Video Tutorial Will Describe about various constraints we can use with tables. Some of the constraints can used as table level or column level so also known as table level constraints and column level constraints. These command will also work on other versions of database like Oracle 11g Database, Oracle 10g Database, Oracle 9i Database, Oracle 8i Database, Oracle 8 Database and so on. In this video i explain Not Null Constraint, Unique key Constraint, Primary Key Constraint, Foreign Key - Reference key Constraint, Check constraint and user_constraints table. Full Syntax will be given in this video tutorial about how to use these constraints. Along with live example to execute Not Null Constraint, Unique key Constraint, Primary Key Constraint, Foreign Key - Reference key Constraint, Check constraint and user_constraints table . All the keywords, format, mandatory clauses etc are described in this video.
Oracle PL SQL interview question NULL and Order by Clause
 
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Oracle PL SQL interview question NULL and Order by Clause Click here to subscribe to my youtube channel http://www.youtube.com/channel/UCBt6VrxAIb5jLh9HLDcdwtQ?sub_confirmation=1 Oracle Interview questions and Answers at https://www.youtube.com/playlist?list=PLb1qVSx1k1Vr0v4wVyvT3GEuA0J0M4xBm Oracle 18C New features at https://www.youtube.com/playlist?list=PLb1qVSx1k1Vqe06V1tIBcvnslMPWX69bW Oracle 12C New features at https://www.youtube.com/playlist?list=PLb1qVSx1k1VqM1u2IHWzZIgziqejl6wx- Oracle PLSQL records and collections at https://www.youtube.com/playlist?list=PLb1qVSx1k1VpAFTXopXvAh_D3PLcTntdm
Views: 639 Siva Academy
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: 2709 Adel Sabour
Oracle SQL Tuning with NOT NULL Constraints
 
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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: 410 SkillBuilders
Oracle - SQL - Check Constraint
 
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Oracle - SQL - Check 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 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: 24685 Caleb Curry
NOT NULL Constraint in Oracle Database
 
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NOT NULL Constraint in Oracle Database
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: 1662 Siva Academy
Tutorial 12- UNIQUE AND NOT NULL CONSTRAINT
 
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Learn about UNIQUE AND NOT NULL CONSTRAINT in PostgreSQL.
Views: 14951 Programming Guru
Oracle - SQL - Managing Constraints
 
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Oracle - SQL - Managing Constraints Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Anadi Sharma, Tutorials Point India Private Limited.
What is the Difference between Primary Key and Unique Key - Database Tutorial 14
 
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Database Tutorial. This video is about Database Fundamentals. I hope this series of videos can help those who want to be Database Professionals. I will cover various database technologies including Oracle Database, Microsoft SQL Server database and Sybase. Video: What is the Difference between Primary Key and Unique Key (Video 14 in the Database Tutorial Series) (Common for Oracle/Microsft SQL Server/Sybase /MySQL)
Views: 36282 Sam Dhanasekaran
How to create Unique Constraint on Column for already existing Table - Part 97
 
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SQL Server / T-SQL Tutorial Scenario: You are working as SQL Server developer, you need to create Unique Constraint on already existing table called dbo.Customer on column SSN. Link to scripts used in SQL Server / TSQL Tutorial Video http://www.techbrothersit.com/2016/05/how-to-create-unique-constraint-on_6.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: 1199 TechBrothersIT
Oracle Tutorial || Oracle|Adv Sql | Special Characters NULL by basha
 
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Oracle SQL Tutorial 6 - Relationships and Primary and Foreign Keys - Database Design Primer 3
 
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HAPPY VALENTINES DAY!!! Let's talk relationships.. This is the 6th video in your Oracle Database series. We are discussing database relationships which are a key feature of relational database management systems. We first discussed entities and attributes. I talked about how each entity is assigned a table and each attribute is a column within a table. We moved on to the three kinds of relationships. The first was one-to-one. This describes an entity and an attribute. A piece of data that is exclusive to an entity is, by definition, an attribute of that entity. This is stored in one table with the attribute being a column within this table. The second relationship is one-to-many. This relationship is between two entities. The way we properly store this in a database is using a foreign key in the child table. Remember, the child table is the entity on the many side of the one-to-many relationship. Every row within the child table will have a value for the foreign key that references a primary key in the parent table. This assumes that the foreign key field is not optional (NOT NULL). If the foreign key is optional, than a reference is not required but any reference must be valid. The third kind of relationship is a many-to-many relationship. In this situation, we need 3 tables. The many-to-many relationship is broken up into two one-to-many relationships. The intermediary table will associate each entity from one table with the appropriate entities in the other table. There is debate as to whether this table needs a primary key. This is because you can intact use the combination of two foreign keys as a primary key. This works because we will never have two duplicate rows within the intermediary table and the two foreign keys work as a compound key because of this. We finally discussed primary keys and foreign keys. Primary keys are used to keep each row inside of a table unique. If this key is a computer generated number it is known as a surrogate key, otherwise it is known as a natural key. Natural keys have real world meaning. For example, a social security number may work, or an email address (in some situations), etc. Whichever type of key you choose is solely up to you and/or the company you may be working for. 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: 49534 Caleb Curry
Simplest way to create Tables on Oracle 12c
 
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--EMPLOYEE TABLE CREATE TABLE "EMP" ( "EMPNO" NUMBER(4,0), "ENAME" VARCHAR2(10 BYTE), "JOB" VARCHAR2(9 BYTE), "MGR" NUMBER(4,0), "HIREDATE" DATE, "SAL" NUMBER(7,2), "COMM" NUMBER(7,2), "DEPTNO" NUMBER(2,0) ) SEGMENT CREATION IMMEDIATE PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "USERS" ; REM INSERTING into EMP SET DEFINE OFF; Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (5258,'ALEX','MANAGER',null,to_date('25-JAN-89','DD-MON-RR'),1500,500,null); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7875,'Aziz','MANAGER',7839,to_date('17-NOV-97','DD-MON-RR'),5000,1000,10); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7899,'HADI','PRESIDENT',null,to_date('09-MAY-99','DD-MON-RR'),9000,null,10); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (3576,'ABDURAUF','MANAGER',null,null,null,null,null); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (3131,'EBAD','CR',null,to_date('25-JAN-81','DD-MON-RR'),1500,500,null); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7955,'JOHNABRAHM','QWERT',null,to_date('18-JUN-20','DD-MON-RR'),2000,null,30); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (5952,'JENN','MANAGER',null,to_date('25-JAN-81','DD-MON-RR'),1500,500,null); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7369,'SMITH','CLERK',7902,to_date('17-DEC-80','DD-MON-RR'),800,null,20); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7499,'ALLEN','SALESMAN',7698,to_date('20-FEB-81','DD-MON-RR'),1600,300,30); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7521,'WARD','SALESMAN',7698,to_date('22-FEB-81','DD-MON-RR'),1250,500,30); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7566,'JONES','MANAGER',7839,to_date('02-APR-81','DD-MON-RR'),2975,null,20); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7654,'MARTIN','SALESMAN',7698,to_date('28-SEP-81','DD-MON-RR'),1250,1400,30); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7698,'BLAKE','MANAGER',7839,to_date('01-MAY-81','DD-MON-RR'),2850,null,30); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7782,'CLARK','MANAGER',7839,to_date('09-JUN-81','DD-MON-RR'),2450,null,10); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7788,'','ANALYST',7566,to_date('19-APR-87','DD-MON-RR'),3000,null,20); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7839,'KING','PRESIDENT',null,to_date('17-NOV-81','DD-MON-RR'),5000,null,10); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7844,'TURNER','SALESMAN',7698,to_date('08-SEP-81','DD-MON-RR'),1500,0,30); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7876,'ADAMS','CLERK',7788,to_date('23-MAY-87','DD-MON-RR'),1100,null,20); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7900,'JAMES','CLERK',7698,to_date('03-DEC-81','DD-MON-RR'),950,null,30); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7902,'FORD','ANALYST',7566,to_date('03-DEC-81','DD-MON-RR'),3000,null,20); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7934,'MILLER','CLERK',7782,to_date('23-JAN-82','DD-MON-RR'),1300,null,10); Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (5230,'SCARLET','MANAGER',null,to_date('26-JAN-81','DD-MON-RR'),1600,600,null); CREATE UNIQUE INDEX "PK_EMP" ON "EMP" ("EMPNO") PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "USERS" ; ALTER TABLE "EMP" ADD CONSTRAINT "PK_EMP" PRIMARY KEY ("EMPNO") USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "USERS" ENABLE; ALTER TABLE "EMP" ADD CONSTRAINT "FK_DEPTNO" FOREIGN KEY ("DEPTNO") REFERENCES "DEPT" ("DEPTNO") ENABLE;
Views: 72 Fareed Ullah
Oracle - SQL - Constraints
 
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Oracle - SQL - Constraints Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Anadi Sharma, Tutorials Point India Private Limited.
47. UNIQUE KEY in SQL (Hindi)
 
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Please Subscribe Channel Like, Share and Comment Visit : www.geekyshows.com
Views: 23673 Geeky Shows
SQL NOT NULL Constraint Telugu | WHAT IS NOT NULL constraints-vlr training
 
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For All sql videos in telugu http://www.vlrtraining.in/sql-training-videos-telugu/ In Telugu: SQL NOT NULL Constraint Telugu WHAT IS NOT NULL constraints? MySQL NOT NULL Constraint sql not null query not null in mysql MySQL NOT NULL Constraint The NOT NULL constraint enforces a column to NOT accept NULL values. This enforces a field to always contain a value, which means that you cannot insert a new record, or update a record without adding a value to this field. In English: download sql study material Website: http://www.vlrtrain.in/2016/09/download-sql-files.html Learn SQL sql tutorial for beginners sql commands oracle sql tutorial sql tutorial advanced mysql tutorial sql tutorial video SQL Tutorial, Tutorials SQL
Views: 871 VLR Training
Common Oracle SQL Tuning Errors - Lesson 4: Insure Index Use
 
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Lesson 4: Improve SQL response time by NOT suppressing index usage. All lessons and many more tutorials are FREE at https://www.skillbuilders.com/free-oracle-database-tutorials/common-oracle-sql-tuning-errors/. Don't Code Filters (aka conditions, predicates, where clauses) that prevent or suppress index use! Attend an online hands-on class with Oracle Certified Master John Watson. Learn more : https://www.skillbuilders.com/course/oracle-12c-sql-tuning-for-developers-and-dbas/.
Views: 155 SkillBuilders
Oracle - SQL - Creating Sequences
 
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Oracle - SQL - Creating Sequences Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Anadi Sharma, Tutorials Point India Private Limited.
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: 97 YourSmartCode
SelectTec | Aula Nº 12 |Create Table Primary key - Oracle SQL Developer
 
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primary key syntax: create table nome_tabela (coluna1 tipo not null, coluna2 tipo, constraint nome_pk primary key (coluna1) );
Views: 3774 SelectTec
Oracle SQL Tutorials ll Querying a table   Part 10f   Single Row Null Functions
 
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CREATE TABLE command in sql/oracle,INSERT command in sql/oracle UPDATE,ALTER PASSWORD command in sql, GRANT command, REVOKE command i, CREATE SYNONYM command in sql/oracle, DELETE command in sql/oracle, ALTER TABLE command in sql/oracle, DROP TABLE command in sql/oracle, CREATE INDEX command in sql/oracle, ALTER INDEX command in sql/oracle, DROP INDEX command in sql/oracle, CREATE VIEW command in sql/oracle, DROP VIEW command in sql/oracle, USING SQL COMMAND Types of SQL Commands The following sections discuss the basic categories of commands used in SQL to perform various functions. These functions include building database objects, manipulating objects, populating database tables with data, updating existing data in tables, deleting data, performing database queries, controlling database access, and overall database administration. The main categories are DDL (Data Definition Language) DML (Data Manipulation Language) DQL (Data Query Language) DCL (Data Control Language) Data administration commands Transactional control commands Defining Database Structures Data Definition Language, DDL, is the part of SQL that allows a database user to create and restructure database objects, such as the creation or the deletion of a table. Some of the most fundamental DDL commands discussed during following hours include the following: CREATE TABLE ALTER TABLE DROP TABLE CREATE INDEX ALTER INDEX DROP INDEX CREATE VIEW DROP VIEW Manipulating Data Data Manipulation Language, DML, is the part of SQL used to manipulate data within objects of a relational database. There are three basic DML commands: INSERT UPDATE DELETE Selecting Data Though comprised of only one command, Data Query Language (DQL) is the most concentrated focus of SQL for modern relational database users. The base command is as follows: SELECT This command, accompanied by many options and clauses, is used to compose queries against a relational database. Queries, from simple to complex, from vague to specific, can be easily created. The SELECT command is discussed in exhilarating detail during Hours 7 through 16. A query is an inquiry to the database for information. A query is usually issued to the database through an application interface or via a command line prompt. Data Control Language Data control commands in SQL allow you to control access to data within the database. These DCL commands are normally used to create objects related to user access and also control the distribution of privileges among users. Some data control commands are as follows: ALTER PASSWORD GRANT REVOKE CREATE SYNONYM You will find that these commands are often grouped with other commands and may appear in a number of different lessons throughout this book. Data Administration Commands Data administration commands allow the user to perform audits and perform analyses on operations within the database. They can also be used to help analyze system performance. Two general data administration commands are as follows: START AUDIT STOP AUDIT Do not get data administration confused with database administration. Database administration is the overall administration of a database, which envelops the use of all levels of commands. Database administration is much more specific to each SQL implementation than are those core commands of the SQL language. Transactional Control Commands In addition to the previously introduced categories of commands, there are commands that allow the user to manage database transactions. COMMIT Saves database transactions ROLLBACK Undoes database transactions SAVEPOINT Creates points within groups of transactions in which to ROLLBACK SET TRANSACTION Places a name on a transaction Transactional commands are discussed extensively during Hour 6, "Managing Database Transactions."
SQL tutorial 73: NVL2 SQL null function By Manish Sharma RebellionRider
 
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Part 2: SQL Null Function NVL2 learn the concepts of NVL null function in this tutorial with examples and all the Interview concepts covered ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog : http://bit.ly/nvl2-null-function Previous Tutorial ► NVL function https://youtu.be/aRoTR5Jn6K0 ------------------------------------------------------------------------- ►►►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: 22661 Manish Sharma
Oracle SQL Tutorial 5 - Database Integrity - Database Design Primer 2
 
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This is the second video in the 5 database design videos in my oracle sql tutorial series. This video discusses database integrity. Database integrity is broken up into 3 sections: entity integrity, referential integrity, and domain integrity. Entity integrity focuses on the primary key. A primary key should be unique, NOT NULL, and never changing. It should refer to only one individual entity. Referential integrity focuses on protecting the relationships between entities of different tables. When creating relationships between tables, you will associate a column with another column in a different table. Individual entities inside of this table should have relationships with individual entities in the other table. For example, a comment table might have a user_id column. Each individual comment (each row), should have a user_id that points to a user_id in the user table. We protect referential integrity with what are known as foreign key constraints. Domain integrity focuses on the allowed values within a database. This one is probably the most complex because there are so many different things you can do to protect this, some of which involve a server side scripting language to add even more complex rules such as regular expressions. Fortunately, Oracle SQL is a pretty big database system and surely has lots of features that can be used to allow domain integrity. 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: 49319 Caleb Curry
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: 5163 radhikaravikumar
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: 43083 TheSSScreations
Oracle Constraints
 
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Oracle SQL Tutorials For Full Course Experience Please Go To http://mentorsnet.org/course_preview?course_id=4 Full Course Experience Includes 1. Access to course videos and exercises 2. View & manage your progress/pace 3. In-class projects and code reviews 4. Personal guidance from your Mentors
Views: 20436 Oresoft LWC
Oracle SQL PLSQL 12C Tutorial 9 - DISTINCT Command, Unique Data
 
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This Video Tutorial Will Describe how to get DISTINCT OR unique values or data from a table in oracle 12C version. This command will also work on other versions of database like Oracle 11g Database, Oracle 10g Database, Oracle 9i Database, Oracle 8i Database, Oracle 8 Database and so on. Whenever you create a new table in oracle, sometimes you just insert the duplicate data or sometimes you need to get only some columns of data which are duplicate but the row is unique. In that case, you need this DISTINCT clause. Full Syntax will be given in this video tutorial about how to get unique records from oracle database table. Along with the live example to get DISTINCT records. All the keywords, format, mandatory clauses etc are described in this video.