Difference between revisions of "DEFAULT Column Constraint"
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==Purpose== | ==Purpose== | ||
Column constraint to set a default value for the specified column | Column constraint to set a default value for the specified column | ||
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==Example== | ==Example== | ||
<code lang="recital"> | <code lang="recital"> | ||
| − | + | ALTER TABLE customer; | |
| − | + | ADD COLUMN dateref DATE DEFAULT date() | |
| − | ALTER TABLE customer ADD COLUMN dateref | + | |
| − | + | ||
| − | + | ||
</code> | </code> | ||
==Products== | ==Products== | ||
| − | Recital | + | Recital, Recital Server |
[[Category:Documentation]] | [[Category:Documentation]] | ||
[[Category:SQL]] | [[Category:SQL]] | ||
Latest revision as of 11:20, 22 December 2009
Purpose
Column constraint to set a default value for the specified column
Syntax
DEFAULT <expr>
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 DEFAULT column constraint is used to set a default value for the specified column. The <expr> must evaluate to the same data type as the target column. The column's value can subsequently be updated.
Example
ALTER TABLE customer; ADD COLUMN dateref DATE DEFAULT date()
Products
Recital, Recital Server
