A B C
\ / /
D E
\ /
F
/ \
G H
The Clear_All message is simple. It clears every table in the entire DDO structure.
Clear_All propagate up and down.
The Clear message clears the Main_File of the DDO and then propagates up the DDO structure
Clears propagate up.
For example:
If clear were sent to A_DD, table A would be cleared. The other tables would be unaffected.
If clear were sent to D_DD, tables D, A, and B would be cleared. The other tables would be unaffected.
If clear were sent to G_DD, tables G, F, D, A, B, E and C would be cleared. Only table H would be unaffected.
The above assumes there are no relates-to constraints in place. Clear and Find propagation rule are changed by relates-to constraints. This is discussed in DDO Propagation and Relates-to Constraints.