Difference between Network and Relational data model
1. Network Data Model :
It is advance version of hierarchical data model. To organize data it uses directed graphs instead of tree-structure. In this child can have more than one parent. It uses concept of two data structures i.e., Records and Sets.
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In the above figure, Project is root node which has two children i.e. Project 1 and Project 2. Project 1 has 3 children and Project 2 has 2 children. Total there are 5 children i.e Department A, Department B and Department C, they are network related children as we said that this model can have more than one parent. So, for Department B and Department C have two parents i.e. Project 1 and Project 2.
2. Relational Data Model :
The relational data model was developed by E.F. Codd in 1970. Their are no physical links as they are in hierarchical data model. Following are properties of relational data model :
- Data is represented in form of table only.
- It deals only with data not with physical structure.
- It provides information regarding metadata.
- At the intersection of row and column there will be only one value for tuple.
- It provides a way to handle queries with ease.
Difference between Network and Relational Data Model :
|Network Data Model||Relational Data Model|
|It organizes records to one another through links or pointers.||It organizes records in form of table and relationship between tables are set using common fields.|
|It organizes records in form of directed graphs.||It organizes records in form of tables.|
|In this relationship between various records is represented physically via linked list.||In this relationship between various records is represented logically via tables.|
|There is lack of declarative querying facilities.||It provides declarative query facility using SQL.|
|Complexity increases burden on programmer for database design as well as data manipulation.||As physical level details are hidden from end users so this model is very simple to understand.|
|Retrieval algorithms are complex but symmetric.||Retrieval algorithms are simple and symmetric.|
|There is partial data independence in this model.||This model provides data independence.|
|VAX-DBMS, DMS-1100 of UNIVAC and SUPRADBMS’s use this model.||It is mostly used in real world applications. Oracle, SQL.|