DATABASE

2.1 INTRODUCTION TO DATABASE

1. Data is a computer resource.

a) People and computers capture and process data to extract meaaning from it.

b) Therefore, data storage must be accessible and organized in a computer processing structure.

2. Data has both fields and values.

3. What would happen to a piece of data newly entered into a computer system?

a) Data is kept in the computer memory.

b) However, computer memory is volatile¹:

i. Data can be overwritten by new inputs.

ii. Data is lost when the computer is shut down.

c) To preserve data, it is transferred into a more permanent storage.

i. The computer copies the file from memory to a non-volatile storage medium.

ii. Non-volatile storage media include magnetic tapes/disks and optical disks.

iii. A text file has extensions such as “.txt” and “.log” that tell the operating system the type of file it is.

iv. Non-text files such as image (.bmp), audio (.wav) and post-script (.pdf) files cannot be viewed through a text editor. Instead, a suitable program is needed to display or play the file content.

4. A file is managed by a file processing system or a database system.

^1. Volatile memory needs a power supply to retain the stored information.