Comparison among Hierarchical Model, Network Model and Relational Model:
Data structure:
Hierarchical Model:
• A) It is one to one or one to many relationship.
• B) It is based on parent child relationship.
Network model:
• A) It follows the many to many relationship.
• B) A record can many have parent as well as many children.
Relational model:
• A) one to one. one to many , and many to many relationship.
• B) based on relation data structure
Data manipulation :
Hierarchical model:
• A) Not any independent stand alone query interface.
• B) Retrieve algorithms are complex and asymmetric.
Network data model:
• A) codasyl(conference on data system language)
• B) retrieve algorithms are complex and symmetric
Relational data model:
• A) Relational data model are what bring many sources into common query (such as sql)
• B) Retrieve algorithms are simple and symmetric.
Data integrity:
Hierarchical Data Model:
• A) cannot insert any information of a child who does not have any parent.
• B) multiple occurrence of child record with lead to problems of inconsistency during the update operation.
• C) deletion of parent results in deletion of child record.
Network model
• A) does not suffer any insertion anomaly
• B) it is free from update anomalies
• C) edit free delete anomalies
Relational model
• A) does not suffer any insert anomaly
• B) free from update anomalies because of normalization process.
• C) free from delete anomalies.
