The EXTFNAPIV4_DESCRIBE_COL_IS_UNIQUE attribute indicates if the column is unique in the table. Used in a describe_column_set scenario.
Description
True, if the column is unique within the table. This property is valid only for table arguments.
Usage
The UDF can set this property if it knows the result table column value is unique. The server uses this information during the Optimization state. The UDF can set this property only for argument 0.
Returns
On success, returns the sizeof(a_sql_byte) or:
- EXTFNAPIV4_DESCRIBE_NOT_AVAILABLE
– if the attribute was not available to set. 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 –
set error returned if the describe buffer is not the size of a_sql_byte.
- EXTFNAPIV4_DESCRIBE_INVALID_STATE –
set error returned if the query processing state is not Optimization.
- EXTFNAPIV4_DESCRIBE_INVALID_PARAMETER –
set error returned if the arg_num is not zero.
- EXTFNAPIV4_DESCRIBE_INVALID_ATTRIBUTE_VALUE –
set error returned if the UDF attempts to set this attribute to a value other than 0 or 1.
Query Processing States
Valid in: