(9)What are some of the prominent data base models?


Answer: Following are some of the prominent data base models:


(1)Hierarchical Database Model: 



  • This model is arranged logically in an inverted tree pattern.
  • In this model, records are logically organized into a hierarchy of relationships.
  • All records in hierarchy are called Nodes. 
  •  Each node is related to the others in a parent-child relationship. The top parent record in the hierarchy is called the Root Record.
  • Each parent record may have one or more child records, but no child record may have more than one parent record.
  •  Thus, the hierarchical data structure implements one-to-one and one-to-many relationships.

(2)Network Database Model:

  • This model views all records in sets. Each set is made up of an owner record and one or more member records.  
  • The network model can bring out redundancy in data more efficiently than in the hierarchical model.
  • Unlike the hierarchical mode, the network model permits a record to be a member of more than one set at one time. This allows for many-to-one and the many-to- many relationship types. 
  •  Network databases directly address the location of a record on disk. This gives excellent retrieval performance.


(3)Relational Database Model:

  • In a relational database, all the tables are related by one or more fields.
  • Through this common field, it is possible to connect all the tables in the database.
  • For each table, one of the fields is identified as a Primary Key, which is the unique identifier for each record in the table. Primary Key is used to join or combine data from two or more tables.
  • Three key terms of this model are Relations, Attributes, and Domains. A relation is a table with columns and rows. Attribute is a named column of the relation and the domain is the set of values the attributes can take.

(4)Object Oriented Database Model:

  •  An object- oriented database is a set of objects. Each object is an independently functioning application or program, assigned with a specific task to perform.
  • OODM is designed to manage all these independent programs to quickly process the large and complex requests. An Object-Oriented Database provides a mechanism to store complex data such as images, audio and video, etc