Data Storage Hierarchy

Data Storage Hierarchy in database.

Data in computer is classified in a hierarchy. Different terms are used to describe data of different levels in the hierarchy. Data are logically organized into:

i)Bits ii) Fields  iii)Records iv)Files  V) Databases

i)Bits: Bit is a smallest unit of data recognized by computer. Eight bit make on byte. A byte is used to represent a character like ‘7’, ‘T’, ‘<’, ‘$’.

ii)Fields: A field is a combination of one or more characters. It is the smallest unit of data that can be accessed by the user. A field is identified uniquely by field name.

iii) Records: A group of related fields is known as record. For Example, a student’s record includes a set of fields about the student such as Student ID, Name, Address, Email and Phone etc.

iv)Files: A file or data file is a collection of related records. Files are stored in disk like hard disk, CD-ROM or DVD-ROM etc. A student file may contain the records of hundreds of students. Each student’s record consists of same fields but each fields contains different data.

V)Database: Database can be defined as an organized collection of related data. The word “organized” means that data is stored in such a way that the user can store, manipulate and retrieve data easily. The word “related” means that a database is normally created to store the data about a particular topic.