The SQL Server Upgrade Wizard has been tested extensively. Microsoft upgraded literally thousands of production databases to determine problems that might be encountered and ways to handle them appropriately. Microsoft worked with ISVs and businesses to upgrade SQL Server 6.x databases to SQL Server 7.0 to ascertain requirements for backward compatibility. Microsoft assisted its internal information technology department with the upgrade to SQL Server 7.0.
Because of this testing, the SQL Server Upgrade Wizard and the backward compatibility modes changed during development to meet the needs of customers.
In addition to backward compatibility support in SQL Server 7.0, Microsoft implemented several other projects to help ensure the integrity and simplicity of the upgrade process.