I have 2 tables.
First table is parent
COLLECTIONS_OF_MAPS
| id | title |
|---|---|
| 50013 | Geological Map Series |
| 50014 | Climate Map Series |
Second table is a child (but whilst describing map layers, it also has entries that are more like group layers, like parents to child maps within the same table, so there is a recursion element here) - this is then realised in a treeview control in software, just for context purposes.
MAP_LAYERS
| id | parent_layer_id | name |
|---|---|---|
| 1233 | 50013 | Hillshade |
| 1228 | 50013 | Cultural Data |
| 1231 | 50013 | Rock Types |
| 1235 | 1233 | Offshore Hillshade |
| 1234 | 1233 | Onshore Hillshade |
| 1229 | 1228 | World Cities |
| 1230 | 1228 | World Countries |
| 1245 | 1228 | World Rivers |
| 1270 | 1231 | Sedimentary Rock |
| 1271 | 1231 | Igneous Rock |
| 1272 | 1231 | Metamorphic Rock |
I have just shown an example for the first map collection - "Geological Map Series".
As you can see it the MAP_LAYERS parent_layer_id column references entries from BOTH tables; it's parent and itself.Can I create a foreign key rule to that references the ids of itself and or its parent table?
