This preview shows page 1. Sign up to view the full content.
Unformatted text preview: byte).
Level 2 - Field - Multiple related characters are combined to form a field.
Level 3 - Record - Multiple related fields are combined to form a record.
Level 4 - File - Multiple related records are combined to form a file.
Level 5 - Database - Multiple related records are combined to form a file.
1. Bit. The smallest item of data is a single binary digit (a bit), either a 0 or a 1.
2. Character. Multiple related bits are combined to form a character (or byte).
For example, the letter M, the number 8, and the special character $ are characters.
Whereas the bit is the basic unit of primary and secondary storage, the character is
the basic unit for human perception.
3. Field. Multiple related characters are combined to form a field. For example,
if we are processing employees' data of a company, we may have an employeecode field, an employee-name field, hours worked field, an hourly-pay-rate field, a
tax-rate-deduction field, etc.
A field is a meaningful collection of related
characters. It is the smallest logical data entity that is treated as a single unit in
data processing. Note that a field may sometimes have a single character, such as
sex code may be represented as M or F.
4. Record. Multiple related fields are combined to form a record. For example,
an employee record will contain the fields containing the data of an employee,
such as the employee's code, name, hours worked, pay-rate, tax-rate deduction,
and so forth. Similarly, a student record will contain the fields containing the data
of a student. Thus, a record is a collection of related fields that are treated as a
5. File. Multiple related records are combined to form a file. For example, a
collection of all the employee records of a company would be an employee file.
Similarly, a collection of all the inventory records of a company forms an
inventory file. Thus, a. file is a number of related records that are treated as a unit.
Notice that every record in a file has the same set of fields. Each record in a file is
View Full Document
This document was uploaded on 04/07/2014.
- Spring '14