Difference between revisions of "SQL Constraints"
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Yvonne.milne (Talk | contribs) (→Column Constraints) |
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|[[CHECK Column Constraint|CHECK]] | |[[CHECK Column Constraint|CHECK]] | ||
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| + | |[[CHECKUNIQUE Column Constraint|CHECKUNIQUE]] | ||
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|[[CHOICES Column Constraint|CHOICES]] | |[[CHOICES Column Constraint|CHOICES]] | ||
Revision as of 13:02, 18 March 2020
Purpose
To define rules that help to provide data integrity
See Also
ALTER TABLE, CREATE TABLE, GRANT, REVOKE
Description
A constraint is used to define rules that help to provide data integrity. There are two different types of constraints, TABLE constraints, which do not require any column information and column constraints, which are specific to the column name specified. You must have ALTER privilege on the table. The table will be locked for EXCLUSIVE use during the operation.
Table Constraints
| CHECK |
| ERROR |
| FOREIGN KEY |
| INDEX |
| KEY |
| ONAFTERDELETE |
| ONAFTERINSERT |
| ONAFTERUPDATE |
| ONCLOSE |
| ONBEFOREDELETE / ONDELETE |
| ONBEFOREINSERT / ONINSERT |
| ONOPEN |
| ONBEFOREUPDATE / ONUPDATE |
| PRIMARY KEY |
| UNIQUE |
