Open
SQL Server
Can only run on Windows, without the slightest openness, the stability of operating system systems is very important to the database. Windows9x Series products are focused on desktop applications, NT server only for small and medium enterprises. And the reliability, security, and scalability of Windows platforms are very limited. It is not as time-tested as UNIX, especially when it comes to dealing with the critical business of large amounts of data.
Oracle
Can be run on all major platforms (including Windows). Full support for all industrial standards. Adopt a fully open policy. Enables customers to choose the solution that best suits them. Full support to developers.
DB2
Can be run on all major platforms (including Windows). Most suitable for mass data. DB2 is the most widely used enterprise class, and almost 85% of the world's 500 largest companies use DB2 database servers, while the country accounts for about 5% of the 97.
scalability, parallelism
SQL Server
Parallel implementation and coexistence models are not mature. It is difficult to handle the increasing number of users and data volumes. Scalability is limited. Oracle
Parallel servers extend the capabilities of Windows NT by enabling a set of nodes to share work in the same cluster, providing high-availability and highly scalable clusters of solutions. If WindowsNT does not meet the needs, users can move the database to UNIX.
DB2
DB2 has a good parallelism. The DB2 extends the database management to the parallel, multi-node environment. A database partition is a part of a database that contains its own data, indexes, configuration files, and transaction logs. A database partition is sometimes called a node or a database node.
Security
SQL Server
No security certificate was obtained.
Oracle Server
Obtain the highest certification level ISO standard certification.
DB2
Obtain the highest certification level ISO standard certification.
Performance
SQL Server
Poor performance when multiuser
Oracle
The highest performance, keeping windowsnt under the tpc-d and Tpc-c world records.
DB2
Suitable for Data warehouse and online things processing, high performance.