Difference between revisions of "REFERENCES Column Constraint"
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==Purpose== | ==Purpose== | ||
Column constraint to create a relationship to an index key of another table | Column constraint to create a relationship to an index key of another table | ||
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==Syntax== | ==Syntax== | ||
| − | REFERENCES <cTableName> | + | REFERENCES <cTableName> TAG <cTagName> |
| − | + | ||
==See Also== | ==See Also== | ||
[[ALTER TABLE]], [[SQL Constraints|CONSTRAINTS]], [[CREATE TABLE]] | [[ALTER TABLE]], [[SQL Constraints|CONSTRAINTS]], [[CREATE TABLE]] | ||
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==Description== | ==Description== | ||
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The REFERENCES column constraint is used to create a relationship to an index key of another table. The value of a column which has the REFERENCES column constraint set is validated by checking that it already exists as a value in the referenced index key. | The REFERENCES column constraint is used to create a relationship to an index key of another table. The value of a column which has the REFERENCES column constraint set is validated by checking that it already exists as a value in the referenced index key. | ||
| − | The name of the referenced table is specified in <cTableName>. The index tag to reference is specified in <cTagName>. | + | The name of the referenced table is specified in <cTableName>. The index tag to reference is specified in <cTagName>. |
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==Example== | ==Example== | ||
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POtotal n(10,2)) | POtotal n(10,2)) | ||
</code> | </code> | ||
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==Products== | ==Products== | ||
| − | + | Lianja, Lianja Server | |
[[Category:Documentation]] | [[Category:Documentation]] | ||
[[Category:SQL]] | [[Category:SQL]] | ||
Latest revision as of 10:58, 29 January 2016
Purpose
Column constraint to create a relationship to an index key of another table
Syntax
REFERENCES <cTableName> TAG <cTagName>
See Also
ALTER TABLE, CONSTRAINTS, CREATE TABLE
Description
A constraint is used to define rules that help to provide data integrity. Column constraints 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.
The REFERENCES column constraint is used to create a relationship to an index key of another table. The value of a column which has the REFERENCES column constraint set is validated by checking that it already exists as a value in the referenced index key.
The name of the referenced table is specified in <cTableName>. The index tag to reference is specified in <cTagName>.
Example
CREATE TABLE supplier; (SuppId i PRIMARY KEY,; SuppName c(40) UNIQUE) CREATE TABLE purchase_order; (POid i PRIMARY KEY,; SuppId i REFERENCES supplier TAG SuppId,; POtotal n(10,2))
Products
Lianja, Lianja Server
