3D AutoCAD 2004/2005: One Step at a Time

25.1 Databases – A Brief Refresher

A database organizes information (data).

Databases begin their organization by placing information into spreadsheet-like tables. A database may contain one or many tables. For example, a petrochemical plant may have tables for valves, vessels, piping, foundations, and so forth.

We divide data in the tables into categories or criteria called fields. Fields appear as columns in the table. Thus, a table of valves in our petrochem plant might include fields such as Manufacturer, Price, Rating, and Size.

We call data about a specific item a record. Records appear as rows in the table and contain informational entries for some or all of the criterion fields. For example, a specific valve might hold the following data: Ball (in the Type field), 2" (in the Size field), and Vogt (in the Manufacturer field). Databases may contain millions of records.

Rows and columns meet in individual cells. A cell contains a single piece of information about the specific record (row). The piece of information falls into the category defined by the field (column).

You can search a database for specific information or cross-referenced information by doing a query. This makes databases irreplaceable wherever they're used!

Popular database applications include MS Access, DBase, and FoxPro.