The EXTFNAPIV4_DESCRIBE_COL_CONSTANT_VALUE attribute indicates the constant value of a column. Used in a describe_column_get scenario.
Description
The value of the column, if it is constant for the statement lifetime. If EXTFNAPIV4_DESCRIBE_COL_IS_CONSTANT for this column returns true, this value is available. This property is valid only for table arguments.
Usage
For columns of input tables that have a constant value, the value is returned. If the value is unavailable, then NULL is returned.
Returns
On success, returns the
sizeof(a_sql_byte), if the value was returned, or:
- EXTFNAPIV4_DESCRIBE_NOT_AVAILABLE
– the attribute is not available to get. Returned, if the column is not involved in the query, or if the value is not considered constant.
On failure, returns one of the generic describe_column errors, or:
- EXTFNAPIV4_DESCRIBE_BUFFER_SIZE_MISMATCH – get error returned, if the describe buffer is not the size of a_sql_byte.
- EXTFNAPIV4_DESCRIBE_INVALID_STATE – get error returned, if the
query processing phase is not greater than Initial.
- EXTFNAPIV4_DESCRIBE_INVALID_PARAMETER – get error returned, if the specified argument is not an input table.
Query Processing Phases
Valid in:
- Annotation phase
- Query Optimization phase
- Plan Building phase
- Execution phase