Documentation

Constraining Updates and Deletes

Sometimes you need to 'close' a record, such as an order or a general ledger batch, and allow now further changes to it. This can be done by attaching constraint chains directly to the table.

For a complete description of chain syntax, see the prior page on general constraints, and the page on calculated values. This page shows only the specifics of preventing deletions or updates.

table ledgerbatches:
    module: ledger
    uisort: 200
    description: Ledger Batches
    
    chain delete_pre:
        test 00:
            compare: @flag_closed = Y
            return: Batch is closed, cannot delete
    chain update_pre:
        test 00:
            compare: @flag_closed = Y
            return: Batch is closed, cannot delete

In the example above we have put two constraint chains onto the table of general ledger batches. These chains work exactly like general constraints, except for these two details:

• The specially-named chain "delete_pre" is used to prevent deletions.
• The specially-named chain "update_pre" is used to prevent updates.

Future Required Feature

The constraints shown above actually lack a feature required to be totally complete. Although it is natural to constrain updates and deletes on closed records by regular users, sooner or later somebody has to come along and purge out the rows. In a future release of Andromeda we will support the "INGROUP" comparison operator to allow a constraint to function based on the user's group membership. This would allow a "purge" group to delete the rows, where normal users could not.