Database Concepts

What is a database

Many of the terms used in databases have been taken from the traditional filing system. In a traditional filing system, data was stored in files e.g. payroll file, customer file etc. Each of these files contains a number of records; the customer file would contain a record for each customer. Each record contained a number of fields to store data such as Name, Address and Telephone number

Modern database systems are a collection of tables, which are linked via relationships. Each table is made up of fields that define the type of data that you want to store in the table. Each table contains data held in records; a table can have zero records up to millions of records. The database is stored on computer media using a filing system

Tables - Tables are set up to store data on a particular type of data. For instance you might have a table containing customer details, a table containing stock and so on

Fields - Each table contains a number of fields that define the type of data that the table will hold. The main types of data are numeric and text, but modern databases usually have a large list of more defined data types. For instance instead of numeric you can set the data type as currency and so on. You can limit the size of these fields, which helps to keep the overall size of the database to a minimum

Records - Each table will contain a number of records. These records contain the actual data. For instance a stock table would have a separate record for every item of stock. These records can be altered, deleted and added to


Source: svuonline.org