Followings are some popular database models:
§ Distributed Database
§ Object Oriented Database
§ Client Server Database
§ Knowledge Database
These databases help us to provide the organisation services from any location e.g. banking and mobile phone services.
In this databases are distributed at various locations of organisation but these databases are connected with each others to provide services from anywhere.
Distributed databases works on two techniques:
§ In Replication Techniques same database and resources are maintained at all the locations of organisation and these are connected with each other using network that resources are replicated at each location.
§ Like all the bank’s branches, regional offices and head office would maintain similar resources.
§ This technique is a very high costly technique normally not used for creating distributed databases.
§ In Partitioning Technique each location maintains its own database and resources but at the same time at one common place like head office all the sharable data elements are also maintained.
§ All location databases are connected with the common database to access the data of other locations to provide services from any location.
§ This is a popular technique of creating distributed databases.
§ Banks etc. uses this technique for creating distributed databases.
Object Oriented Databases:
§ The Object Oriented databases model is the latest development in database technology.
§ In this all the elements of database are modelled as objects and these objects can be linked together to create entire database structure.
§ In this model objects are formed in hierarchical structure using a concept known as Inheritance.
§ Object Oriented Database is based on the principle of Object Oriented Programming Language that write once use many times.
§ The structure once created can be used anywhere.
§ These models provide efficient database.
§ The Object Oriented Database helps to increase the productivity of databases designer for design of database and users for use of database.
§ The Object Oriented Model is based on collection of objects and Object contains values in the form of data fields.
§ An object also contains methods that operate on object.
Client Server Database:
§ These databases are also known as Database Server that provides data related services.
§ In this one or more database server is used and many clients interact with these servers to obtain requested data e.g. ATM machine is a client and it always remain connected with bank database server to provide banking services to customers.
§ There are two popular methods to use Client/Server Database model
o Two tier
o Three or N tier
§ In two tier the client directly interact with database server.
§ And in three tier client interact with database through a intermediate server known as application server.
§ These databases are collection of knowledge of experts in an organised form.
§ In this type of database the expert’s historical knowledge for problem solutions are organised to provide help for solutions of future problems.
§ Such database are part of DSS (Decision Support System), Expert System and EIS(Executive Information System).