28.1 Introduction

Data are the lifeblood of industrial process operations. The levels of efficiency, quality, flexibility, and cost reductions needed in today's competitive environment cannot be achieved without a continuous flow of accurate, reliable information. Good data management ensures the right information is available at the right time to answer the needs of the organization. Databases store this information in a structured repository and provide for easy retrieval and presentation in various formats.

28.2 Database Structure

The basic structure of a typical database consists of records and fields. A field contains a specific type of information for example, the readings from a particular instrument or the values of a particular laboratory test. A record contains a set of related field values, typically taken at one time or associated with one location in the plant. In a spreadsheet, the fields would usually be the columns (variables) and the records would be the rows (sets of readings).

In order to keep track of the information in the database as it is manipulated in various ways, it is desirable to choose a key field to identify each record, much as it is useful for people to have names so we can address them. Figure 28-1 shows the structure of a portion of a typical process database, with the date and time stamp as the key field.