The following table provides an overview of the functions that IBM Informix ODBC Driver provides for modifying rows and collections.
| Function | Modification | Row | Collection |
|---|---|---|---|
| ifx_rc_delete() | Delete an element | No | Yes |
| ifx_rc_insert() | Insert an element | No | Yes (See the following table.) |
| ifx_rc_setnull() | Set the row or collection to null | Yes | Yes |
| ifx_rc_update() | Update the value of an element | Yes | Yes |
The following table describes the collection locations into which you can insert an element. You can insert an element only at the end of a SET or MULTISET collection because elements in these types of collections do not have ordered positions.
| Beginning | Middle | End | |
|---|---|---|---|
| List | Yes | Yes | Yes |
| Multiset | No | No | Yes |
| Set | No | No | Yes |
Each row and collection maintains a seek position that points to the current element in the row or collection. When the row or collection is created, the seek position points to the first element that is in the row or collection. All calls to client functions share the same seek position for a row or collection buffer. Therefore, one client function can affect the seek position for another client function that uses the same buffer handle. The following table describes how client functions use and modify the seek position.
| Client Function | Acts On | Changes |
|---|---|---|
| ifx_rc_delete() | At the specified position | Sets the seek position to the value after the one that was deleted |
| ifx_rc_fetch() | At the specified position | Sets the seek position to the specified position |
| ifx_rc_insert() | Before the specified position | Sets the seek position to the specified position |
| ifx_rc_update() | At the specified position | Sets the seek position to the specified position |