ensure Unique
Executes the given block and catches ExposedSQLException to handle unique constraint violations.
If a unique constraint violation is detected (SQLState starts with "23"), it raises UserIssue.AlreadyExists.
Executes the given block and catches ExposedSQLException to handle unique constraint violations.
If a unique constraint violation is detected (SQLState starts with "23"), it raises UserIssue.AlreadyExists.