Question

In my application (client-server) I need to edit some rows (from a database), and as long as they are edited it needs nobody to be able to edit also. This is done by transactions of course. The problem is that in a client-side environment the transactions is managed on the server side, so the client that edits the rows can’t access the transaction directly. (I’m working with PHP in that situation but think that the same approach is adopted in other technologies also). So I need to keep transaction opened (for keeping rows locked for editing) until the client finishes the edit.
In PHP, persistent connection won’t help because they can be broken from other clients located in the same host with the aforesaid client. Do you have any ideeas for my scenario?

thank you.

Answer 1

Usually such cases are handled through business locks that you set directly on the objects, or on the parent of the objects.

Add a column such “inedition” that you set to true when user claims for edit, and set to false when user validate/cancel its edit.

Be aware that some users transactions are likely to be lost before that you unlock the row, so you’ll probably require:

• either a periodic treatment that unlock rows
• either a functionnal screen from which the user or an admin can unlock the rows that remained locked.

Edit:
This kind of solution is used whenever you do not want to rely on database specific feature, such Oracle “Select for update”. In Java an EJB statefull bean can keep a reference to the transaction from UI to database. There might be solutions using PHP for Oracle or other database specific feature regarding transactions, depending on databases.