What are the types of databases? __ Database

Large databases are: Oracle, Informix, DB2

Medium databases are: SQL Server, Sybase

Small databases are: Access, MySQL, and so on.

First, open

1. 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 in processing large databases.

2. 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.

3. Sybase ASE

Can be run on all major platforms (including Windows). However, due to early Sybase and OS integration is not high, so VERSION11.9.2 the following version requires more OS and DB-level patches. In a multi platform mixed environment, there will be some problems.

4. 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.

5.Informix

Informix-se is suitable for UNIX and windowsnt platforms, Informix-online runs on Unix operating systems, provides multi-threaded servers, supports symmetric multiprocessing, and is suitable for large applications.

Informix has strong portability and good compatibility

Second, scalability, parallelism

1. SQL Server

Parallel implementation and coexistence models are immature, it is difficult to deal with the increasing number of users and data volumes, scalability is limited.

2. Oracle

A parallel server expands the capabilities of WINDOWNT by enabling a set of nodes to share work in the same cluster, providing a solution for high-availability and highly scalable clusters. If WindowsNT does not meet the needs, users can move the database to UNIX. Oracle's parallel servers have a fairly high level of integration with the cluster mechanisms of various UNIX platforms.

3. Sybase ASE

Although there is a DB switch to support its parallel server, the DB switch is technically immature and supports only ASE servers of version 12.5 or more. DB switch technology requires a server to act as a switch, causing some trouble on the hardware.

4. DB2

It has 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. Database partitions are sometimes referred to as node security.

Third, security certification

1. SQL Server

No security certificate was obtained.

2. Oracle Server

Obtain the highest certification level ISO standard certification.

3. Sybase ASE

Obtain the highest certification level ISO standard certification.

4. DB2

Obtain the highest certification level ISO standard certification.

Four, performance

1. SQL Server

Poor performance when multiuser

2. Oracle

The highest performance, keeping the open platform under the tpc-d and Tpc-c world records.

3. Sybase ASE

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

4. DB2

Higher performance applies to data warehousing and online processing of things.

V. Client Support and Application mode

1. SQL Server

c/S structure, only support Windows customers, you can use ADO, DAO, OLE DB, ODBC connection.

2. Oracle

Multi-level network computing, supporting a variety of industrial standards, can use ODBC, JDBC, OCI and other network clients to connect.

3. Sybase ASE

c/S structure, you can use ODBC, Jconnect, Ct-library and other network customer connections.

4. DB2

Cross-platform, multi-layer architecture, support ODBC, JDBC and other customers.

Six, easy to operate

1. SQL Server

Simple to operate, but only graphical interface.

2. Oracle

More complex, providing both GUI and command lines, which operate the same under WindowsNT and UNIX.

3. Sybase ASE

More complex, providing both GUI and command line. However, the GUI is poor, often not in time, we recommend using the command line.

4. DB2

Simple to operate, providing both GUI and command lines, which operate the same under WindowsNT and UNIX.

Vii. risk of Use

1. SQL Server

Full rewrite of the code, experienced a long period of testing, continuous delay, many features need time to prove. is not very compatible.

2. Oracle

Long-time development experience, completely backward-compatible. has been widely used. There is no risk at all.

3. Sybase ASE

Backward-compatible, but Ct-library program does not benefit transplant.

4. DB2

It is widely used in mega-enterprises and has good backward compatibility. Risk is small.