Difference between revisions of "DESCRIPTION Column Constraint"
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==Purpose== | ==Purpose== | ||
Column constraint to set the column description for the specified column | Column constraint to set the column description for the specified column | ||
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==Syntax== | ==Syntax== | ||
DESCRIPTION <expC> | DESCRIPTION <expC> | ||
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==See Also== | ==See Also== | ||
[[ALTER TABLE]], [[SQL Constraints|CONSTRAINTS]], [[CREATE TABLE]], [[LABEL()]] | [[ALTER TABLE]], [[SQL Constraints|CONSTRAINTS]], [[CREATE TABLE]], [[LABEL()]] | ||
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==Description== | ==Description== | ||
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The DESCRIPTION column constraint is used to set the column description for the specified column. The <expC> is a character expression of up to 25 characters. | The DESCRIPTION column constraint is used to set the column description for the specified column. The <expC> is a character expression of up to 25 characters. | ||
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==Example== | ==Example== | ||
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</code> | </code> | ||
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[[Category:Documentation]] | [[Category:Documentation]] | ||
[[Category:SQL]] | [[Category:SQL]] | ||
Revision as of 08:00, 7 December 2012
Contents
Purpose
Column constraint to set the column description for the specified column
Syntax
DESCRIPTION <expC>
See Also
ALTER TABLE, CONSTRAINTS, CREATE TABLE, LABEL()
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 DESCRIPTION column constraint is used to set the column description for the specified column. The <expC> is a character expression of up to 25 characters.
Example
ALTER TABLE customer; ADD COLUMN dateref DATE; DEFAULT date(); DESCRIPTION "Date Reference"
