MSDE is a data store based on SQL Server technology, but it is designed and optimized for use on smaller computer systems, such as a single user computer or small workgroup server.
Because MSDE is based on the same database engine as SQL Server, most Access projects or client/server applications run unchanged on either MSDE or SQL Server. However, unlike SQL Server, MSDE has a two-gigabyte database size limit, does not support symmetrical multiprocessing (SMP), and cannot be a publisher for a transactional publication (although it can be a subscriber to transactional publications).
If you installed the redistributable MSDE available with Microsoft Office 2000 Developer as the database engine for your team solutions, you can upgrade later to SQL Server.
To upgrade the redistributable MSDE to SQL Server