Transcript Components of .NET Provider

Architecture of ADO.NET
Introduction
• ADO.NET is a collection of classes, objects, methods and
properties that manage data access from relational databases
with in the .NET platform.
• These
collections
are
organized
in
the
namespaces
System.Data, System.Data.Oledb, System.Data.Sqlclient.
Architecture
Components of ADO.NET
ADO.NET provides two central components.

.NET Data Provider

DataSet
.NET Data Provider
• Data provider acts as a bridge between an application and
database.
• It is used to retrieve data from a database and send back to
the database after changes.
Components of .NET Provider
.NET Data Provider consist of four object components.

Connection object

Command object

DataReader object

DataAdapter
Components of .NET Provider
Connection object
• These objects are used to create a connection to the database for
moving data between the database and user application.
• This connection can be created using oleDbConnection or
SqlConnection object.
• Open(), close() and dispose() are the methods of connection
object used to open and close the defined connection.
Example
• DIM con As SqlConnection
• Con=New SqlConnection()
• Con.ConnectionString=“data source = asdf; initial
catalog = stud; user id = sa; pwd =“
• con.open()
Explanation
• data source - name of the SQL server which is to be connected.
• initial catalog - name of the database
• user id – SQL login account
• pwd – is the password
• The user must close the connection after using it. This is done by
either close or dispose method. con.close()
Command objects
• These objects are used to read, add, update and delete
records in a database.
• These operations are done by the objects OledbCommand
or SqlCommand and the method ExecuteReader() or
ExecuteNonQuery().
Methods in Command object
ExecuteReader()
• It is used to execute the commands and retrieve rows from
the database.
ExecuteNonQuery()
• It is used to execute the commands without retrieving any
row.
Example
• DIM con As SqlConnection
• DIM cmd As SqlCommand
• cmd.Connection = con
• Cmd.CommandText=“select * from studTable”
DataReader object
• These objects are used to read row wise data in read only
format from databases.
• The SqlDataReader or OleDbReader object is used
depending on the database.
• The ExecuteReader() method is used to retrieve a row from
database.
Methods in DataReader
Read
• It is used to obtain a row from the result of the query.
GetString
• It is used to access a column value in a selected row.
Close
• This method must be called after the use of DataReader object.
Example
• DIM cmd As SqlCommand
• DIM myReader As SqlDataReader
• myReader = cmd.ExecuteReader()
• Do While myReader.Read()
• MsgBox (myReader.GetString(0) & Vbcr & myReader.GetString(1))
• Loop
• myReader.Close()
DataAdapter object
• This object is used to exchange data between a database and a
dataset.
• It reads data from the database to the dataset and then write the
changed data back to the database.
• The Fill()
method
is used
to write the result of
SelectCommand into the dataset.
Properties of DataAdapter
• SelectCommand for accessing rows in a database
• InsertCommand for inserting rows in to the database
• UpdateCommand for modifying rows in the database
• DeleteCommand for deleting rows
Example
• DIM Myadapter As New SqlDataAdapter
• Myadapter.SelectCommand=mycomm
• DIM Mydataset As New DataSet()
• Myadapter.Fill(MydataSet,studTable)
• con.close()
DataSet
• DataSet is a virtual storage of records retrieved from the
database.
• It contains collection of Tables, Primary key and other related
information.
DataSet
The End
…… Thank You …..