Contents Index Relational database concepts Relations between tables

ASA Getting Started
   Databases and Applications
    Relational database concepts

Database tables


In a relational database, all data is held in tables, which are made up of rows and columns.

A database containing several tables.

Each table has one or more columns, and each column is assigned a specific data type, such as an integer, a sequence of characters (for text), or a date. Each row in the table has a single value for each column.

For example, a table containing employee information may look as follows:

emp_ID emp_lname emp_fname emp_phone
10057 Huong Zhang 1096
10693 Donaldson Anne 7821
Characteristics of relational tables 

The tables of a relational database have some important characteristics:

The following table lists some of the formal and informal relational database terms describing tables and their contents, together with their equivalent in non-relational databases. This manual uses the informal terms.

Informal relational term Formal relational term Non-relational term
Table Relation File
Column Attribute Field
Row Tuple Record
What do you keep in each table? 

Each table in the database should hold information about a specific thing, such as employees, products, or customers.

By designing a database this way, you can set up a structure that eliminates redundancy and the possible inconsistencies caused by redundancy. For example, both the sales and accounts payable departments might enter and look up information about customers. In a relational database, the information about customers is stored only once, in a table that both departments can access.

For more information about database design, see Designing Your Database.

For instructions on how to create a table, see Lesson 3: Design and create a table.


Contents Index Relational database concepts Relations between tables