Database Model
A set of rules and standards that define how the database organizes data is called database model. It also defines how users view the organization of data.
Types of Database Models
There are three types of database models. These models are as follows:
- Hierarchical Model
- Network Model
- Relational Model
1. Hierarchical Model:
The hierarchical model arranges records in hierarchy like an organizational chart. Each record type in this model is called a node or segment. A node represents a particular entity. The top-most node is called root. Each node is a subordinate of the node that is at the next higher level.
A higher level nodes is called parent and lower level node is called child. A parent node can be have one or many child nodes. A child node can have only one parent node. This kind of structure is often called inverted tree.
2. Network Model:
The network model is similar to hierarchical model. The difference is that child node can have more than one parent nodes. The child nodes are represented by arrows in network model. It requires more complex diagram to represent a database. It also provides more flexibility than hierarchical model.
3. Relational Model:
Relational Model is the most commonly used database model. It is more flexible than hierarchical and network database models. The relational model consists of simple relations. A relation is a term used for table. A relation represents a particular entity.
It is used to store information about the entity. The relationships are based on the data of the entities. The relationship between entities is represented by the following diagram
