SQL constraints

Data Control Language (DCL) Commands (GRANT and REVOKE), DCL Operations (Grant privileges to a users and Revoke (remove) privileges from Users) and Database Administration.
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Tejaswini
Posts: 36
Joined: Sun Mar 31, 2019 6:39 am

SQL constraints

Post by Tejaswini » Wed Apr 17, 2019 4:06 pm

What are SQL constraints?

sai
Posts: 25
Joined: Mon Apr 01, 2019 10:52 am

Re: SQL constraints

Post by sai » Wed Apr 17, 2019 4:11 pm

SQL constraints are the set of rules that impose some restriction while insertion, deletion or updation of data in the databases. In SQL we have both column level as well as table level constraints which are applied at columns and tables respectively.
Some of constraints in SQL are - Primary Key, Foreign Key, Unique Key, Not NULL, DEFAULT, CHECK and Index constraint.

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