The mi_qual_constisnull() accessor function
The mi_qual_constisnull() function determines whether the arguments to a qualification function include a NULL constant.
Syntax
mi_boolean mi_qual_constisnull(MI_AM_QUAL_DESC *qualDesc);- qualDesc
- Points to the qualification descriptor.
Usage
The Return value column shows
the results of the mi_qual_constisnull() function
for various constant arguments.
| Sample function | Description | Return value |
|---|---|---|
| function(column, 10) | The arguments specify the explicit non-NULL constant value 10. | MI_FALSE |
| function(column, NULL) | The arguments specify an explicit NULL value. | MI_TRUE |
The form function(column,?) cannot occur because the qualification descriptor that the database server passes to the am_beginscan or am_getnext purpose function contains values for any host-variable argument.
Do not call this function from the am_scancost purpose function. Use mi_qual_constisnull_nohostvar() instead.
Return values
- MI_TRUE
- Indicates that the arguments include an explicit NULL-valued constant.