How many types of DBMS?

 Types of DBMS:

 There are six types of DBMS. They are as follows: 

1. Hierarchical DBMS 

2. Network DBMS 

3. Relational DBMS 

4. Distributed DBMS 

5. Object Oriented DBMS 

6. Object Relational DBMS

 1. Hierarchical DBMS:

 It is called HDBMS because it is based on hierarchical DBMS. This data model was developed by IBM in 1968 and introduced in IMS (Information Management System). This model is like structure of a tree with the records forming the nodes and fields forming the branches of the tree. In this model, a parent record can have several child records but a child can have only one parent record. 

•  Advantages of HDBMS: 

1. It is very simple, analytical and natural method of implementing record relationships. 

2. This model is useful when there is some hierarchical character in the database. 

3. It is most popularly used data model by everyone because it is very easy to adopt, implement and modify. 

• Disadvantages of HDBMS: 

1. It cannot represent all the relationships that occurred in the real world.

 2. It cannot demonstrate the overall data model for the enterprise because of the non-availability of actual data at the time of designing the data model.

 3. This data model is used only when there is hierarchical character in the concerned database. It cannot represent many to many relationship.

 4. Insert anomaly/problem: it is not possible to insert data about a new dependent if its superior record is not available.

 5. Delete anomaly: Deleting data in a hierarchical database lets to loss of many information.

 6. Update anomaly: In HDBMS, Updation of record and data is also an another problem. For example, suppose you want to change the address of a student from Delhi to Patna, then you will face two problems: 

a) You need to search the entire database to find every occurrence of that particular student and make changes everywhere. Wherever his/her details is appearing, if you miss out a single occurrence, you will face inconsistency problem. 

b) The student might shown as being in Patna at one place and at Kankarbagh another place.