Difference between revisions of "SQL Constraints"
From Lianjapedia
Yvonne.milne (Talk | contribs) |
Yvonne.milne (Talk | contribs) |
||
| Line 91: | Line 91: | ||
[[Category:SQL|Constraints]] | [[Category:SQL|Constraints]] | ||
[[Category:Reference]] | [[Category:Reference]] | ||
| + | [[Category:Database Triggers]] | ||
Revision as of 09:49, 2 February 2018
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 |
Column Constraints
| AUTO_INCREMENT |
| AUTOINC |
| CALCULATED |
| CHECK |
| CHOICES |
| DEFAULT |
| DESCRIPTION |
| ERROR |
| FOREIGN KEY |
| HELP |
| NOCPTRANS |
| NOT NULL |
| NULL |
| PICTURE |
| PRIMARY KEY |
| RANGE |
| RECALCULATE |
| REFERENCES |
| SET CHECK |
| UNIQUE |
