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Choosing a DBMS
It is important to choose the right DBMS. While many intranet projects are based on existing architectures and databases, projects related to the Internet open the door to change. The following is worth considering when choosing a DBMS:
- Tools to facilitate the importation of external data in various formats, including binary formats, should accompany the DBMS. Such tools are available from both database vendors and third parties.
- The DBMS should be supported on a variety of platforms and operating systems in case the project grows faster than expected and the platforms limits are reached too quickly.
- The DBMS should offer optimum and proven security.
- The DBMS must be able to handle hundreds of simultaneous connections during peaks.
- For greater convenience, the DBMS should be remotely administrable. For Internet service, the service must be provided 24 hours a day.
- Other resource-hogging user or network applications running on the same platform should not be affect the DBMS on a stability point-of-view (this is more related to the operating system than to the DBMS software).
- The DBMS must support online backup facilities as well as consistency checking and repair.
- Replication facility is an extra.
All relational DBMSs (RDBMS) offer nearly equivalent facilities, security, and performance levels. ODBMSs (Object Database Management Systems) are superior to RDBMSs as regards retrieval of multimedia content. A performance improvement factor of 10 or more is sometimes observed, which is important to consider if the database will hold hundreds or thousands of multikilobyte binary objects. ODBMSs are also very attractive to object-oriented developers. Performance sometimes decreases when a large number of relations between entities is present.
Finally, the choice of the DBMS platform seems to be more important than the choice of the DBMS software itself. While personal computer-based DBMSs may be very convenient during the development phase, their cost/performance factor is much higher than open systems-based DBMSs when supporting a relatively high number of simultaneous connections. Do not compare CPU (central processing unit) power because one architecture is not scalable while the other is. Be aware that the I/O (input/output) subsystem is often the bottleneck. Unix is the best platform when thousands of simultaneous TCP/IP network connections are involved because TCP/IP is part of the heart of the operating system.
In addition, you should consider purchasing a DBMS and hardware platform that are fully scalable without involving replication of the data, the DBMS software, and the platform itself. Almost all serious DBMSs may be dynamically reconfigured each time new hardware is added to the platform as, for example, when adding CPU chips on the main board.
Summary
This chapter discussed design issues for the Internet and intranet scenarios, as well as possible implementation choices and platform choices.
This is the end of Part III. The next part is dedicated to complete, working examples using JDBC.
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