Basic Database Tutorial Version 0.2.0 June 9, 2001
This Database Tutorial is written as a basic introduction to databases and database servers.
There are several kinds of databases which include:
- Flat file databases
- Relational databases
- Object databases
- Object relational databases
Flat files are simply files with a table of information which may be seperated by delimeters such as commas, colons, or semi-colons. Relational databases consist of several related tables of simple data. The tables are composed of rows and columns. Object databases store data in an object form rather than in tables. They store attributes and class information, but sometimes they also store and methods (behavior) in the database. Object relational databases are relational databases with data stored in tables, but they have a front end that converts objects to data and data to objects, making it seem to the application that objects are being stored.
Database servers include both a server program that serves remote clients and manages the database. They may use some means of standard communication between client and server to allow management of the data such as structured query language (SQL) for relational database servers.
The most popular databases today are Relational Database Management Systems (RDBMS). However, object database servers may someday overtake the relational database servers.
Relational Databases and Objects
If relational databases are used to store objects, the object must first be disassembled into parts, normalized, and placed in tables. This can take some time to do, and be a labor intensive process required for writing the code. To use the object, it must be reassembled.
Many relational databases are run on one single server and do not use a distributed architecture.
Object Database Servers
Object database servers may use an Object Query Language (OQL) as a standard language for communication. They may use an application programming interface (API) to allow the application to control the data or they may use both the API and OQL.
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