Difference between revisions of "SQL Constraints"
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==Purpose== | ==Purpose== | ||
To define rules that help to provide data integrity | To define rules that help to provide data integrity | ||
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==See Also== | ==See Also== | ||
[[ALTER TABLE]], [[CREATE TABLE]], [[GRANT]], [[REVOKE]] | [[ALTER TABLE]], [[CREATE TABLE]], [[GRANT]], [[REVOKE]] | ||
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==Description== | ==Description== | ||
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====Table Constraints==== | ====Table Constraints==== | ||
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{| class="wikitable" | {| class="wikitable" | ||
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====Column Constraints==== | ====Column Constraints==== | ||
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{| class="wikitable" | {| class="wikitable" | ||
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[[Category:Documentation]] | [[Category:Documentation]] | ||
[[Category:SQL|Constraints]] | [[Category:SQL|Constraints]] | ||
[[Category:Reference]] | [[Category:Reference]] | ||
Revision as of 11:11, 15 November 2012
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 | ONCLOSE |
| ONDELETE | ONINSERT | ONOPEN |
| ONROLLBACK | ONUPDATE | PRIMARY KEY |
| UNIQUE |
Column Constraints
| AUTO_INCREMENT | AUTOINC | CALCULATED |
| CHECK | DEFAULT | DESCRIPTION |
| ERROR | FOREIGN KEY | NOCPTRANS |
| NOT NULL | NULL | PRIMARY KEY |
| RANGE | RECALCULATE | REFERENCES |
| SET CHECK | UNIQUE |
