A database model is a type of data model that determines the logical structure of a database and fundamentally determines in which manner data can be stored, organized, and manipulated.
Historically, in database design, three models are commonly used. They are,
HIERARCHICAL MODEL
In a hierarchical model,
-Data is organized into a tree-like structure.
-Each record or entity has only one parent but can have several children.
-Allow one-to-many relationships.
-First database model proposed by IBM.
-A record search is performed by moving from the top to down until the correct child record is found.
-Each record or entity has only one parent but can have several children.
-Allow one-to-many relationships.
-First database model proposed by IBM.
-A record search is performed by moving from the top to down until the correct child record is found.
NETWORK MODEL
In the network model,
-Data is organized in a graph like structure
-Each record or entity may have multiple parents.
-Allow many-to-many relationships.
-Most popular before being replaced by the relational model.
RELATIONAL MODEL
In relational model,
-Data is organized in the form of 2D tables called relations.
-Rows are termed as tuples, and columns are termed as attributes or fields.
-Each table has a key field that uniquely identifies each row.
-Tables or relations are related to each other through the key field.
-It was introduced by E.F. Codd in 1970.
-Its most commonly used query language is the Structured Query Language (SQL).
