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What is SQL Constraints?

SQL Constraints SQL constraints are used to specify rules for table data. The following are commonly used SQL constraints: NOT NULL - Indicates that a column cannot contain any NULL value. UNIQUE - Does not allow to insert a duplicate value in a column. The UNIQUE constraint maintains the uniqueness of a column in a table. More than one UNIQUE column can be used in a table. PRIMARY KEY - Enforces the table to accept unique data for a specific column and this constraint create a unique index for acc

26th Jul 2018, 7:26 AM
gunas
gunas - avatar
1 Réponse
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In this context, it means requirement.
26th Jul 2018, 7:31 AM
Janning⭐
Janning⭐ - avatar