The comparison among the record based data models in DBMS

HIERARCHICAL MODEL	NETWORK MODEL	RELATIONAL MODEL
It organizes records in form of the tree structure.	It organizes records in form of directed graphs.	It organizes records in form of tables.
Only one to one (1:1) and one to many (l: N) relationships are implemented in this model.	(1:1) and ( 1: N), many to many (M: N) relation­ships implemented.	All the relationships can be implemented easily.
Relations among records arc physically implemented using pointers.	Relations among records are represented physically using linked lists.	Relations among records arc represented logically in the form of rows and columns.
Lack of declarative querying fa­cilities.	Lack of declarative querying fa­cilities.	Provides declarative querying facilities using SQL.
Complexity makes the design of a database difficult.	Complexity increases the bur­den on the 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.
Insertion anomaly exists i.e. In­sertion of a child record without parent record is not possible.	This model does not suffer from insertion anomalies.	This model does not suffer from insertion anomalies. It is very easy to insert records into the tables.
Multiple occurrences of child records lead to inconsistency problems when updation is per­formed.	Due to single occurrences of records no update problems ex­ists.	By use of normalization, the redundancy of data is removed hence updation is very easy to perform.
Deletion anomaly exists. It is difficult to delete the parent records.	No deletion anomaly exists as simple changing position point­ers can be made when the record is deleted.	Free from deletion anomaly because information or records are stored in different tables.
Retrieval algorithms are com­plex and asymmetric.	Retrieval algorithms are com­plex hut symmetric.	Retrieval algorithms are simple and symmetric.
IBM's IMS (Information Man­agement System) is a popular DBMS using this Model.	VAX-DBMS, DMS-JIOO of UNI VAC*, and SUPRA DBMS's use this Model.	Most commonly used in real-world applications. Oracle. SQL Server. Sybase DBMS use this Mode)
Less data independence,	Partial data independence.	Data independence
Basic structure	Basic structure	Basic structure