On Saturday 16 February 2008 02:31:17 pm Michael Hipp wrote: > Some places they call this "optimistic locking". > > User A loads a record into a form and goes to lunch. User B loads the > same record, makes changes, and saves it. User A comes back, types stuff > into that (now stale) record and saves it. Boom, crash, death and mayhem. > > Does Dabo have anything built-in to avoid the "simultaneous, > incompatible edits" problem? > > I've seen this typically handled by having an 'edit_sequence' field on > every table that holds a unique non null sequence value that gets > automatically incremented with every update. And every update must first > check to see if it's stored edit_sequence value matches the one in the > database. If not, it must go back to the user with a very unwelcome > message like "That idiot down the hall edited the record you were > working on so now you have to start over. Sorry." And reload the > refreshed record. > > Does Dabo have anything built-in? > > Thanks, > Michael
No is the general answer. Dabo supports several different database engines and each handles transaction in it's own way. I.e. with Postgres the default would be the last save over writes the record. However, with Dabo only the fields that are changed are saved. The user queries the data. Dabo creates a cursor of the data. User makes changes to one data field. Only that field will be updated. With Postgres there are plenty of tools to change that behavior. For example I can force Postgres to return a data error if the returning user from lunch tried to update. I think you can see why the general answer is NO. -- John Fabiani _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://leafe.com/mailman/listinfo/dabo-users Searchable Archives: http://leafe.com/archives/search/dabo-users This message: http://leafe.com/archives/byMID/dabo-users/[EMAIL PROTECTED]
