About OLEDB connection class :

1. This class is used to open a connection with any type of data base and also used to start transactions.
2. This class is inherited from System. Data. Common .Connection class,

Which is an abstract  class.

AS per above observations , all types of connection classes will be having same method names and same property names.

Properties:-

1. Status:
2. Server version:
3. Connection String:
4. Provider:

Methods:-

1. open ()
2. close ()
3. Dispose ()
4. Begin Transaction

Con. open ();

Con . close ();

Con.  Open ();

About oledb command class :

• This class is used to execute DDL, DML, TCL, QL and Stored procedures.

DDL:  create, alter, drop

DML:  insert, delete, update

TCL: commit, rollback, save point

QL: select

Stored Procedure is a collection of SQL Statements.

Properties:-

1. Connection
2. Command Text
3. Command Type
4. Parameters

Methods:-

1. Execute Non Query () :- is used to execute DDL, DML, TCL and stored procedure.
2. Execute Reader (): need to be used when multiple records are expecting from a select statement.

Execute Reader ()   returns Data reader.

3. Execute Scalar (): Search only for first match, it match is found ,then only first column value will be returned.

EMP 

ENO           ENAME                   SAL

1                  Ravi                         5000

2. Teja 9000
3. Raj 8000
5. .

1000

Select * from EMP ;

Execute Reader  () ALL

Execute Scalar ()  ALL