Difference between revisions of "SQL Constraints"
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|[[DESCRIPTION Column Constraint|DESCRIPTION]]||[[ERROR Column Constraint|ERROR]]||[[FOREIGN KEY Column Constraint|FOREIGN KEY]] | |[[DESCRIPTION Column Constraint|DESCRIPTION]]||[[ERROR Column Constraint|ERROR]]||[[FOREIGN KEY Column Constraint|FOREIGN KEY]] | ||
|- | |- | ||
| − | |[[ | + | |[[HELP Column Constraint|HELP]]||[[NOCPTRANS Column Constraint|NOCPTRANS]]||[[NOT NULL Column Constraint|NOT NULL]] |
|- | |- | ||
| − | |[[ | + | |[[NULL Column Constraint|NULL]]||[[PRIMARY KEY Column Constraint|PRIMARY KEY]]||[[RANGE Column Constraint|RANGE]] |
|- | |- | ||
| − | |[[REFERENCES Column Constraint|REFERENCES]]||[[SET CHECK Column Constraint|SET CHECK]]||[[UNIQUE Column Constraint|UNIQUE]] | + | |[[RECALCULATE Column Constraint|RECALCULATE]]||[[REFERENCES Column Constraint|REFERENCES]]||[[SET CHECK Column Constraint|SET CHECK]] |
| + | |- | ||
| + | |[[UNIQUE Column Constraint|UNIQUE]]|||| | ||
|- | |- | ||
|} | |} | ||
Revision as of 11:14, 14 July 2014
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 |
| ONROLLBACK | ONBEFOREUPDATE / ONUPDATE | PRIMARY KEY |
| UNIQUE |
Column Constraints
| AUTO_INCREMENT | AUTOINC | CALCULATED |
| CHECK | CHOICES | DEFAULT |
| DESCRIPTION | ERROR | FOREIGN KEY |
| HELP | NOCPTRANS | NOT NULL |
| NULL | PRIMARY KEY | RANGE |
| RECALCULATE | REFERENCES | SET CHECK |
| UNIQUE |
