The EXTFNAPIV4_DESCRIBE_COL_IS_UNIQUE attribute indicates if a column is unique in the table. Used in a describe_column_get scenario.
Description
True, if the column is unique within the table. This property is valid only for table arguments.
Usage
If the UDF gets this property, then returns 1 if the column is unique, and 0 otherwise.
Returns
On success, returns the
sizeof(a_sql_byte) or:
- EXTFNAPIV4_DESCRIBE_NOT_AVAILABLE
– if the attribute was unavailable to get. This can happen if the column was not involved in the query.
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 state is not greater than Initial.
Query Processing States
Valid in:
- Annotation state
- Query Optimization state
- Plan Building state
- Execution state