Databases
A database is simply an organized collection of
data. This data is usually organized into a number of records each of which
contains a number
of
fields. Because of their size and complexity and the need to be able to quickly
and easily search for information, a database is usually stored within a
computer and a special program - a database manager or database
management system (DBMS) -
provides an interface between users and the data itself. The DBMS keeps track of where the
information is stored and provides an index so that users can quickly and
easily locate the information they require.
Test your
knowledge 2.5
A manufacturer wishes to distribute a set of data
sheets on a conventional CD-ROM. Each data sheet consists of an Adobe Acrobat
file having a size of 2.8 Mbytes. In addition, the manufacturer has included an
index and other files amounting to a total of 80 Mbytes. Approximately how many
data sheets can be included on a single CD-ROM?
The database manager will also allow users to
search for related items. For example, a particular component may be used in a
number of different products. The database will allow you to quickly identify
each product that uses the component as well as the materials and processes
that are used to produce it.
The structure of a simple database is shown in Figure 2.6. The database consists of a
number of records arranged in the form of one or more tables. Each
record is divided into a number of fields. The fields contain different
information but they all relate to a particular component. The fields are
organized as follows:
Field 1 Key (or index number)
Field 2 Part number
Field 3 Type of part
Field 4 Description or finish of the part
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