CTX_DBBase :: DBStore - Before store handler

The before store handler is called before storing instance data to the transaction or database (DBP_Store event). The event handler is typically used to perform application consistency checks for the instance or update derived persistent data before storing the instance. To prevent infinite loops, do never call Save() in a DBStore() handler.

Updating derived fields might also been done in the DBP_Modify event handler, which acts on the property level rather than on the instance level. This allows more precisely detecting changes on specific fields.

The before store handler can deny creating the data instance by returning YES.

The handler can be overloaded in specialized context class implementations.