Network Database Management System and Hierarchical Database Management System are described and compared

1. NDBMS/HDBMS
- BARATH KUMAR BABU

2. DBMS – DATABASE MANAGEMENT SYSTEM
• DBMS is system software for creating and managing databases.
The DBMS provides users and programmers with a systematic
way to create, retrieve, update and manage data.
• It serves as an interface between the database and end,
ensuring that data is consistently organized and remains easily
accessible.

4. HDBMS - INTRODUCTION
• A DBMS is said to be hierarchical, when the data is organized
like a tree structure. That means, it simply represents the data
using parent – child relationship. It follows one to many
relationship. i.e. All parents can have more than one child, but
each child should have only one parent.
• The parent record at the top of the tree structure is called the
Root record. In this type of DBMS, there is a drawback. If we
want to add a new field or record, it may require to redefine the
entire database in some cases.

5. ADVANTAGES/DISADVANTAGES
• The only advantage of this model is we can easily retrieve the value
without wasting much time - ADVANTAGE
• Because it is designed in one to many relationship a child can have
only a single parent so, redundancy comes into picture because of
data duplication.
• When we want to access the data in this model we need to travel
from the root node step by step to the desired level, which will be
time consuming.
• Only one person can share the database simultaneously.
• If you want to add the new level in between the existing levels. The
user has to reconstruct the entire tree structure but it is “tedious and

6. NDBMS - INTRODUCTION
• A network database consists of a collection of records
connected to one another through links
• A network may have as many connections as it can.
• In DBMS language, a parent can have many children and a child
can have more than one parent. So a Network DBMS will have
many-to-many relationship.

7. ADVANTAGES/DISADVANTAGES
• In hierarchical DBMS, we can have only one parent to a child.
But in Network, we can have more than one. – ADVANTAGE
• Retrieval of data is difficult because more than one parent
exist.

8. HDBMS VS NDBMS
Parent
Level 1
Child
Level 2
Child
Level 2
Child
Level 1
Child
Level 2
Child
Level 2
Child

9. COMPARISON
• Family tree like structure of
database
• 1:1, 1:M Parent-child
relationship is established
• We cannot insert the
information of child who does
not have any parent.
• Database structure look like a
network form
• 1:1, 1:M and Multiple parent-
child relationship is
established
• No member can exist without
an owner

10. CONCLUSION
• Since HDBMS had a major drawback, NDBMS was developed. Like
the hierarchical structure, the network model was unable to
handle ad hoc requests for information easily because its
relationships must be specified in advance, which pointed to the
need for relationship model

11. REFERENCES
• https://searchsqlserver.techtarget.com/definition/database-
management-system
• http://sqlversity.com/hierarchical-dbms/
• http://www.ijarcsms.com/docs/paper/volume3/issue6/V3I6-
0066.pdf
• https://sqlversity.wordpress.com/2013/03/11/network-dbms/
• https://www.youtube.com/watch?v=wR0jg0eQsZA&frags=pl%2
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