Schema Merge Options Dialog

This dialog is used to setup schema merge options and currently opened when you merge tables in the Object list or Table structure diff tabs and the merge includes new NOT NULL columns without DEFAULT values. This operation may fail if the target table already contains data.

for MySQL, schema merge options dialog

Currently there is only one option:

New NOT NULL columns without DEFAULT

This section provides information about the issue and available solutions:

You are about to merge table(s) that include new NOT NULL column(s) without defaults. This operation may fail if the target table already contains data. To prevent this, you can either remove the NOT NULL constraint or specify a DEFAULT value. Then you can merge data and run table definition merge again to resolve any remaining NOT NULL or DEFAULT differences.
WARNING: Default value can be set for only one column. The DEFAULT expression you enter will be used as is, without SQL injection protection.
○ Keep NOT NULL ○ Remove NOT NULL ○ Add DEFAULT (value)

Suggested options:

Keep NOT NULL Keep the NOT NULL constraint on the column(s), the same as in the source database. This may cause the merge to fail if the target table contains existing rows.
Remove NOT NULL Remove the NOT NULL constraint from the column(s). This allows the merge to proceed without requiring a DEFAULT value.
Add DEFAULT Add a DEFAULT value for the column. This option is available only when merging a single NOT NULL column without DEFAULT. Enter the DEFAULT expression in the text field next to this option.

After selecting an option, click OK to proceed with the merge script generation or Cancel to abort the operation.

Last updated: 2026-06-03