Database connectivity in .NetBefore .NET TECHDATABASE:It is used to store,maintain retrieve or manipulate the dataIt is of 3 types:ISAMDBThese are stand alone and n/w unaware database models like for e.g.: ms-excess,dbase VSAMDBThese are n/w aware and client server based databasesFor e.g. : Oracle,Sql-serverINTERNET DATABASEThese can be any database which can be populated on the webFor eg:OLTP DB,OLAP DB,Index Server etc

Normal structureApplicationdatabaseDrivers

Classic ImplementationApplicationdbproDriversWin 32 API

Drawback and SolutionThe limitation of the above model is: It is mandatory for the user to know the host and the destination data types.So the requirement was a database object model to interact with the databases without the knowledge of the Host and the destination data types.Solution : Object Models

Database connectivity using Object ModelsApplicationObject ModelDrivers/ ProvidersProtocolsdbDAORDOADOSQLData Access ObjectsRemote Data ObjectsActiveX Data ObjectsSQL Server Config Manager

For one requirement you have many solutions when to use which modelAPPLICATIONDAORDOADOJET ENGINESODBC DRIVERS (DSN-BASED CONNECTIVITYOLEDB PROVIDERSISAM DBVSAM DBInternet db

DAOIt is a special model to interact with the ISAM db with the support of JET engines.If DAO model is used to interact with the VSAM db,then data inconsistency might occur

RDOIt is a special model to interact with the VSAM db using the ODBC(open database connectivity) drivers.If RDO model is used to interact with the ISAM db as that model performs all the N/W verifications and all the performance of the application might decrease to 10-15%Requirement: An object model to interact any type of DBS in the past and future dbs without any performance lossSolution is ADO

ADOIt is a special model to interact with any type of databases with the support of OLEDB providers or ODBC drivers