Diagrams Affected by Another User’s Changes

In a multiuser environment, a database diagram can be affected by changes other users have saved to:

• A diagram, which other users changed after you opened the diagram.
• Database objects shared between diagrams.
• The database.

For example, a diagram may contain a table that another user deletes or renames. In such a case, the diagram no longer reflects the current state of the database. When you attempt to save the database diagram or selected tables, the Database Changes Detected dialog box notifies you that the database was updated by another user after you opened the diagram.

Alternatively, the Database Changes Detected dialog box also displays a list of database objects that will be affected by you as a result of saving your diagram or selection.

In either case, you can:

• Save the diagram or selection and update the database with all the changes in the list.

  This action will also affect other diagrams that share the same database objects.

  For example, suppose you edit the au_id column in the titleauthors table on your diagram. Another user’s diagram contains the authors table which is related to the titleauthors table by the au_id column. Saving your diagram will affect the other user’s diagram. Similarly, suppose that another user defined a CHECK constraint for the qty column in the sales table. If you delete the qty column and save the sales table, the other user’s CHECKconstraint will be affected.

• Cancel the save action.

  You can then close the diagram without saving it. When you reopen or recreate the diagram, it is synchronized with the database.

• Save a list of the changes.

  You can save the list of database changes shown in the Database Changes Detected dialog box to a text file in the project directory so that you can investigate other users’ changes.

  For example, if another user edited a table that you marked for deletion, before you update the database, you may want to research whether the table should be deleted.