If a deployment script fails, or if it is cancelled, in most circumstances changes are rolled back. SQL Compare uses transactions to do this. However, there are some circumstances when this isn't possible:

• if full-text information must be altered (for example: within a transaction, catalogs can't be dropped, and indexing can't be added to a column)
• if users and roles need to be created, altered, or deleted (for example: within a transaction, a user can't be created, or added to a role)

In these cases, SQL Compare rolls back all the changes it can. Your database will be in an undetermined state and you should run another comparison.

If you've selected the project option Do not use transactions in deployment SQL scripts to remove transactions from the deployment SQL script, no changes are rolled back when the script fails or is cancelled. This may be useful if you want to run a script up to the point of failure; for example, for debugging.

SQL Compare always warns you if it can't roll back changes.