Data file storage constructs

Overview | Masterfile | Transaction | Copy/backup | Special
Data processing

Overview

Data files vary in type depending on their particular purpose. Files may be stored in two ways; On-line and Off-line. There are four basic file types;

Masterfiles

Use

Examples:

Debtors - Names & addresses

Stock - items (codes & descriptions)

Payroll - Employees

Properties:

Transaction files

Use

Contains daily/weekly data processing affecting the masterfile records

Examples:
Debtors - Cash/Credit transactions
Stock - Stock movement
Payroll - Employee timesheets

Special Transaction files:
Audit File
Log file

Properties:

Audit files

Use

Records changes to the database

In an online system a file added to when changes occur.

In an offline system may be original files prior to updating

Properties

Can get very large.

Are usually archived and/or printed regularly.

Log files

Use

Record what has happened,

Examples:

On a system level
Who has logged into the system, when and for how long,
What hardware errors have been encountered.

Properties

This file can become very, very large and is usually managed by a systems administrator in large systems.

Copy/Backup files

Use

Properties

Examples:

Backup files
Use: Saving copies of working files
Properties: Often stored on tape in a compressed and sequential format.

Archive files
Use: Storing data of historical value
Properties: Once stored, fixed in size, May be saved in original form

Special files

Use

Examples
Voice Data File (WAV)
Picture Data file (Bit-mapped and Vector), (BMP, GIF, WMF)
Video Data file (AVI, MOV, MPEG)

Properties

 

[8/9/97 Rev: 15/9/97] © 1997 V/2-Com (Verhaart), P O Box 8415, Havelock North, New Zealand.