1. SQL Server

can only run on windows, without the slightest openness, the stability of the operating system system is very important to the database. windows9X series products are biased towards desktop applications, NT server is only suitable for small and medium-sized enterprises. And windows platform reliability, security and scalability is very limited. It is not as well-tested as unix, especially when dealing with large databases.

2. Oracle

Runs on all major platforms (including windows). Fully supports all industry standards. Uses a completely open strategy. Enables customers to choose the most appropriate solution. Full support for developers.

3. Sybase ASE

Runs on all major platforms (including windows). However, early versions of Sybase below VERSION 11.9.2 require more OS and DB level patches due to poor OS integration. This can be problematic in mixed environments with multiple platforms.

4. DB2

Runs on all major platforms (including windows). The most suitable for massive data. DB2 is most widely used in the enterprise, in the world's 500 largest enterprises, almost 85% of more than with DB2 database server, while the domestic to 97 years about 5%.

Two, scalability, parallelism

1. SQL server

parallel implementation and *** storage model is not mature, it is difficult to deal with the increasing number of users and data volumes, limited scalability.

2. Oracle

Parallel server extends the capabilities of windowsNT by enabling a group of nodes to *** enjoy work in the same cluster, providing a solution for clustering with high availability and high scalability. If windowsNT does not meet the needs, users can move the database to UNIX. oracle's parallel server has a fairly high level of integration with the clustering mechanisms of various UNIX platforms.

3. Sybase ASE

While there is DB SWITCH to support its parallel server, DB SWITCH is not yet mature at the technical level and only supports ASE SERVER of version 12.5 and above. DB SWITCH technology requires a server to act as a SWITCH, which brings about some troubles in hardware.

4. DB2

Has great parallelism.DB2 extends database management to a parallel, multi-node environment. A database partition is a part of the database that contains its own data, indexes, configuration files, and transaction logs. Database partitions are sometimes referred to as node security.

III. Security Certificates

1. SQL server

has not obtained any security certificates.

2. Oracle Server

is certified to the ISO standard, the highest level of certification.

3. Sybase ASE

has been certified to the ISO standard at the highest certification level.

4. DB2

Certified to ISO standards at the highest certification level.

4. Performance

1. SQL Server

Poor performance with multiple users

2. Oracle

Highest performance, holds the world record for TPC-D and TPC-C on an open platform.

3. Sybase ASE

Performance is close to SQL Server, but concurrency on UNIX platforms is better than SQL Server.

4. DB2

Higher performance is suitable for data warehousing and online transaction processing.

V. Client support and application models

1. SQL Server

C/S structure, only supports windows clients, you can use ADO, DAO, OLEDB, ODBC connection.

2. Oracle

Multi-level network computing, supports multiple industry standards, can connect with ODBC, JDBC, OCI and other network clients.

3. Sybase ASE

C/S structure, can connect with ODBC, Jconnect, Ct-library and other network clients.

4. DB2

Cross-platform, multi-tier structure, support for ODBC, JDBC and other clients.

6. Easy to operate

1. SQL Server

Easy to operate, but only the graphical interface.

2. Oracle

more complex, providing both GUI and command line, the same operation under windows NT and unix.

3. Sybase ASE

more complex, providing both GUI and command line. However, the GUI is poor, often not in a timely state, it is recommended to use the command line.

4. DB2

Simple operation, provide both GUI and command line, in windowsNT and unix under the same operation.

VII. Risks of using

1. SQL server

completely rewritten code, after a long period of testing, constant delays, many features need time to prove. Not very compatible.

2. Oracle

Long development experience, fully backward compatible. Widely used. Completely risk free.

3. Sybase ASE

Backwards compatible, but the ct-library program is not portable.

4. DB2

Widely used in giant enterprises, good backward compatibility. Risks are low.