Key Terms in Database Design

To understand the database design process you must have a clear understanding about the key terms which are used in it. In the following section you will be able to define and explain each term separately.

Fields / Attributes

In a formal relational model data are stored in tables. A table is structured as a list of attributes, and in this model a particular column header is identified as a field or an attribute. Each attribute has a unique name. Though attributes can be easily identified, the values of an attribute are all in the same domain.

The orders of the attributes or fields are not relevant.

Data Types

For each field or attribute there will be a particular data type, which will illustrate which type of data can be stored in each field or attributes.Following are some of the data types which can be used.

• Text
• Number
• Currency
• Date/Time
• Lookup Wizard

To understand data types in fields and attributes let us consider the following example will illustrate it better. Imagine you are going to create a database which will store basic details of employee in an organization. It comprises of several tables other than the following employee table. It contains following data types for each field.

Records and Tuples

A database record is made up of one set of tuples for a given relational table.In a relational database, records correspond to rows in each table. A record is a collection of fields, each containing one item of information.

For example, in a student information system, the details of a particular student in a student master table, is a record or tuple of the given relational table.

The following figure shows the relationship of what has been learnt up to now.