Various Forms of Database
There are three forms (models) of database;
1. Relational database.
2. Hierarchical database.
3. Network database.
This is also called a flat-file. It uses a table to represent data and the relationship between the data. A table is made up of rows and columns, and each row represents a record (horizontal), while each column has a unique name. This is referred to as a field (vertical) – Tuples and Attributes.
Students’ database (Information about students’ records in a school)
|Kc 52116||Osuoha Williams||12||M||HARM||JS 3A|
|Kc 31278||Okon John||11||M||H/J||JS 3F|
|Kc 21185||GwaikyaaShienguvan||13||M||PANES’||JS 3J|
|Kc 23345||Mohammed Yusuf||14||M||MCK||JS 3C|
|Kc 42346||Fasanmoye Israel||14||M||HARM||JS 3E|
Staff database – for Employees’(Information about employees’ records in an Organization)
|Kc 207||Yinusa Ahmed||M||LANG||Yobe||Arabic|
|Kc 3215||Okoro Ubah||M||SOC||Imo||Civic Ed|
|Kc 709||Tinubu Monsirat||F||MATHS||Oyo||Maths|
|Kc 999||Godspower Joseph||M||BUS||Bayelsa||Comm|
Customers database (Information about Customers’ records in a Bank)
|Acct. No||Name||Sex||Acct. Type||Credit Bal.||Debit Bal|
This is in the form of a tree structure where records (information) are represented in terms of a parent-child relationship called a one-to-many relationship.
Each element in the structure is called a node. The node at the top of the tree is not a member of any relationship. So it is called a root node e.g
The structure above shows a Principal, Teachers, and Students of Kofa College. The Principal is the root node. The one-to-many relationship is that the principal has many teachers and a teacher has many students.
In this model, there are multiple interrelationships (many-to-many relationships of data). This makes provision for accessing a number of records from more than one record.
For example, many students are offering many subjects. Also, many subjects are being offered by many students.