Relational Database

A relational database is a collection of data organized on the basis of logical or natural association between items. Relational databases provide the basis for Web search programs.

W3E References:

spiders

Spiders, worms or web walkers or crawlers all build searchable Web databases.

Structured Query Language (SQL)

Structured Query Language (SQL) is perhaps the most common way to extract data from a relational database system.

Detail:

There are three traditional types of database management systems: hierarchical, relational, and network. (Object-oriented database systems are currently in development.)

Relational databases are commonly structured as a series of tables. The rows represent records and the columns represent fields that are common to all records. The data is controlled by a database management system (DBMS). Current popular database systems include Oracle, Microsoft's SQL Server, IBM's DB2, SQL/DS, and IMS, and smaller consumer products such as dBase, Access, Foxpro, and Paradox.

A number of programs automatically explore the World Wide Web, building databases of titles, headings, and URLs. These databases form the basis for Web search programs.