ADO.NET

Database: Database is a repository fro maintaining the data with support of tables.
Table: Table is representing the collection of rows, columns and constraints.
Database is classified into two types.

1. ISAM (Index Sequential Access Mode) Database 
2. VSAM (Virtual Sequential Access Mode) Database

ISAM (Index Sequential Access Mode) Database:

These are standalone databases which are executed with in a local system.

For example: MS Access, Excel etc.

VSAM (Virtual Sequential Access Mode) Database:

These is a client-serve based database which are executed with in the network.

For example: SQL Server, Oracle etc.

Evaluation of ADO.NET:

Their are three database connectivity models supported by Microsoft before .NET.

1. DAO (Data Access Object)
2. RDO (Remote Data Object)
3. ADO (ActiveX Data Object)

 DAO ( Data Access Object ):

It is a special data model for interacting with ISAM Database with the support of JET engines. DAO is not aware of network hence it cannot be used for interacting with the network related databse such as SQL Server,Oracle etc.

RDO (Remote Data Object):

It is data model introduced to interact with ISAM and VSAM Databases with the support of ODBC (Open Database Connectivity) drivers.

RADO models depends on the DSN (Data Source Name) by registering with the operating system using ODBC drivers.This model is tightly coupled with operating system and hence whenever migrations or updations has to performed then it will be very difficult.

ADO (ActiveX Data Object):

It is a very powerful data model which is used fro interacting with any type of database with the support of OLEDB(Object Linking and Embedding Database) providers.

ADO is a COM(Component Object Model) based data model and hence all the limitations of COM are applicable on this model such as Dll hell, Dll locking etc.

A new powerful data access model to interact with any database for .NET technology which is called as ADO.NET

•  It is representing with System.Data namespace.
• Data Access architectures are two types

1. Connected oriented architecture.
2. Disconnected oriented architecture.