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SQL limitations

Why do we use SQL limitations? Which constraints can we use while making a database in SQL?
Mar 27 '19 #1
1 1757
SQL Constraints are used to set the principles for all tables in the table. On the off chance that any imperatives get abused then it can prematurely end the activity that caused it.
Constraints are characterized while making the database itself with CREATE TABLE explanation or even after the table is made once with ALTER TABLE statement.
There are 5 noteworthy constraints we use as a part of SQL, for example,

NOT NULL: That demonstrates that the section must have some value and we can’t leave it invalid
Interesting: We use this constraint to guarantee that each line and section has one of a kind value and we make sure we don’t rehash any values in some other line or segment
Essential KEY: We use this constraint as a part of the relationship with NOT NULL and UNIQUE imperatives, for example, on one or the mix of in excess of one segments to distinguish the specific record with a one of a kind character.
Remote KEY: Generally, we use it to guarantee the referential uprightness of data in the table and furthermore coordinates the incentive in one table with another utilizing Primary Key
CHECK: We use it to guarantee whether the incentive in sections satisfies the predetermined condition.
Mar 28 '19 #2

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