Applied Theory: Using ADSI to Migrate from Windows NT 4.0 to Windows 2000

Exploiting the directory service provider abstraction methods found in the ADSI COM objects, ADSI lends itself to becoming an extremely powerful tool to aid the migration from the Windows NT user domain SAM to Windows 2000's Active Directory.

Unlike the Windows NT SAM, the Active Directory can become the central information store for all pertinent employee data. By extending the schema of the Active Directory to add enterprise-specific data fields to each user record, you now have the ability to allow consolidation of multiple external data stores into a single location. In this regard, select data from the corporate Human Resources database can be stored in the Active Directory to allow the creation of extremely robust directory service enabled applications.

Many third-party domain migration tools simply do not account for any fields beyond those originally contained in the NT SAM. If the Active Directory is to become a central repository for user information, these tools provide little functionality beyond the simple creation of a new user object in the Active Directory. To populate the extended fields of the Active Directory, a second process must be instantiated to pull data from an external database source, creating additional development effort.

Rather than investing in third-party migration products (most of which use ADSI) for a one-time migration, forward-thinking managers should instead task internal development teams to learn to use ADSI with Visual Basic. In the same process used to create a user object in the Active Directory, the extended attributes of each object can be populated with information from an external source, such as the Human Resources database or virtually any ODBC-compliant database platform. Such a scripting effort would reduce the efforts required to later populate this information in the directory after using these third-party utilities. In addition, the time invested to learn ADSI will provide not only for the migration process itself, but also will allow administrators to provide better support for the enterprise after the migration.

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