BaseNow

 

  Search
   

  Help

Screen shots

Compare editions

Online help

Quick-start videos

System requirements

License agreement

Known issues

  Support

 Forums

Technical support

Feedback

 About the author

 Company

Contact

Privacy policy

  Features

BaseNow architecture

Database tools

BaseNow Agent

Tables and views

SQL Query Builder

Import/export data

  Subscribe

Stay informed about any major changes. Click here to subscribe

 

About indexes

An index helps database to find and sort records faster. When you create a database and tune it for performance, you should create indexes for the columns used in queries to find data.

Indexes in databases are similar to indexes in books. In a book, an index allows you to find information quickly without reading the entire book. In a database, an index allows the database program to find data in a table without scanning the entire table.

You can create indexes based on a single field or on multiple fields. Multiple-field indexes enable you to distinguish between records in which the first field may have the same value.

The performance benefits of indexes do come with a cost. Tables with indexes require more storage space in the database. The commands that insert, update, or delete data can take longer and require more processing time. You should ensure that the performance benefits outweigh the extra cost.

Which fields to index?

You'll probably want to index fields you search frequently, fields you sort, or fields that you join to fields in other tables in queries. The primary key of a table is automatically indexed, and you can't index a field whose data type is OLE Object. If many of the values in the field are the same, the index may not significantly speed up queries. For other fields, you should consider indexing a field if the following apply:

 The field's data type is Text, Number, Date/Time, or Currency.

 You anticipate searching for values stored in the field.

 You anticipate sorting values in the field.

 You anticipate storing many different values in the field.


Related Topics:

How to create an index

About Indexes Manager

Create and change indexes

About primary keys

Set or change the primary key

Columns

About tables

Relationships

[Home] [Download] [Screen Shots] [Details] [Support] [Purchase]

Copyright © 1997-2005 Gate Comm Software. All Rights Reserved.