Column defaultFor the definition
of a default value, a DefaultConstantExpression is an
expression that does not refer to any table. It can include constants,
date-time special registers, current schemas, users, roles, and null:
DefaultConstantExpression:
NULL
| CURRENT { SCHEMA | SQLID }
| USER | CURRENT_USER | SESSION_USER | CURRENT_ROLE
| DATE
| TIME
| TIMESTAMP
| CURRENT DATE | CURRENT_DATE
| CURRENT TIME | CURRENT_TIME
| CURRENT TIMESTAMP | CURRENT_TIMESTAMP
| literal
For details about Derby literal values, see
.
The values in a DefaultConstantExpression must be
compatible in type with the column, but a
DefaultConstantExpression has the following additional type
restrictions:
- If you specify USER, CURRENT_USER, SESSION_USER, or CURRENT_ROLE, the column must be a
character column whose length is at least 8.
- If you specify CURRENT SCHEMA or CURRENT SQLID, the column must be a
character column whose length is at least 128.
- If the column is an integer type, the default value must be an
integer literal.
- If the column is a decimal type, the scale and precision of the default
value must be within those of the column.