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Disconnected Architecture in VB.NET
By:
Ambreen Gillani

VB.NET
Disconnected Architecture
Data Sets, Data Tables, Data Adapters, Stored
Procedures and managing their transections.

Disconnected Architecture in ADO.NET

ADO.NET
 ADO.NET is part of the .NET framework technology that allows
you to access and modify data from different data sources.
 It supports many types of data sources such as Microsoft SQL
Server, MySQL, Oracle, and Microsoft Access.
 The .NET Framework provides a number of data providers that
you can use. These data providers are used to connect to a data
source, executes commands, and retrieve results.

ADO.NET
 ADO.NET was built for a disconnected architecture, so it enables
truly disconnected data access and data manipulation through its
Dataset Object, which is completely independent from the Data
Source.
 The two key components of ADO.NET are Data Providers and Data
Set
 ADO.net uses dataset object for disconnected architecture And
data adapter fills it.

DataSet
 The DataSet is the central component in the ADO.NET
Disconnected Data Access Architecture.
 A DataSet is an in-memory data store that can hold multiple
tables at the same time.
 DataSets only hold data and do not interact with a Data Source.
 One of the key characteristics of the DataSet is that it has no
knowledge of the underlying Data Source that might have been
used to populate it.
 DataSet is disconnected architecture gets all records at once
and closes connection and are available even after connection
is closed
 A DataSet is made up of a collection of tables, relationships, and
constraints

DataSet
Syntax:
 The Data Set is not connected directly to a Data Source through a
Connection object when you populate it. It is the Data Adapter that
manages connections between Data Source and Dataset by fill the
data from Data Source to the Dataset and giving a disconnected
behavior to the Dataset.
 The Data Set contains Data Tables. The Data Tables contains Data
Row and Data Columns. A Data Set or a Data Table can be used with
a Command and a Data Adapter object to store query results.

. Program Example for DataSet:

Data Adapter
 The Data Adapter acts as a bridge between the Disconnected Objects
 Data Adapter is a part of the ADO.NET Data Provider.
 Data Adapter provides the communication between the Dataset and
the Data source.
 We can use the DataAdapter in combination with the DataSet Object.
 The Data Adapter can perform Select , Insert , Update and Delete SQL operations in the
Data Source.
 DataAdapter - A DataAdapter object is used to fill a DataSet/DataTable with query results.
 Syntax:
Dim adapter As New SqlDataAdapter
adapter.SelectCommand = New SqlCommand(sql, sqlCnn)
Dim ds As New DataSet
adapter.Fill(ds)

Data Adapter
Adapter.Update(dataset_variable,”Table_Name”)
 This command is used to update database after working on
dataset.
 This can be thought of as the adapter between the
connected and disconnected data models.
 A Command object will be used to execute the query and
a DataAdapter will use this Command object and fill the
query results coming from the database into
a DataSet/DataTable.

How adapter fills dataset in disconnected
architecture
and how dataset is used further…..

DataTables
The DataTable class is a member of the System.Data namespace within the
.NET Framework class library.
A database table commonly has a column or group of columns that uniquely
identifies each row in the table. This identifying column or group of columns is
called the primary key.
Adding Primary Key For specific Table:
table1.PrimaryKey = New DataColumn()
table1.Columns(“RollNo")

DataTables
Syntax:
Imports system.data
Dim dt as DataTable = new DataTable()
dt.TableName = “Records”
’or use the DataTable(string TableName) constructor
Dim dt DataTable = new DataTable(“Records”)

DataTables
Adding A column to a Data Table:
dim dc as datacolumn = new datacolumn()
dc.columnName=“Names”
dc.datatype=GetType(String)
dc.defaultvalue=0
‘At the end
dt.column.add(dc)
 (Dt is the datatable variable defined previousely)

DataTables
Adding A row to a Data Table:

DataTables
Creating A complete Data Table:
' Create new DataTable instance.
Dim table As New DataTable
' Create three typed columns in the DataTable.
table.Columns.Add(“RollNo", GetType(Integer))
table.Columns.Add(“Name”, GetType(String))
table.Columns.Add(“Age", GetType(Integer))
' Add three rows with those columns filled in the DataTable.
table.Rows.Add(7756, “Ambreen Gillani", 20)
table.Rows.Add(7779, “Maira Abbas", 20)
table.Rows.Add(7764, "Hafiza Kawish Amin", 20)

Insert, Update Delete Command in
disconnected architecture

Guidelines….
 In disconnected architecture we work on dataset and that
dataset is filled by the data adapter.
 First the connection Is opened and all the data is copied
from data source to dataset by the adapter and then the
connection Is closed.
 Adapter.fill(ds) is used.
 Then we perform operations on that dataset and after
working, adapter.update command is required to update
the changes made to the datasource.

Display Records in Disconnected
Architecture
Display records using DataSet:

Searching In disconnected Architecture
 Searching For a specific Record :

Stored Procedures:
 A stored procedure is a precompiled executable object that
contains one or more SQL statements.
 Using stored procedures, database operations can be
encapsulated in a single command, optimized for best
performance, and enhanced with additional security.
 To call a stored procedure from VB.NET application, set the
CommandType of the Command object to Stored Procedure
and command text to that name you specified to Stored
Procedure.

Complete code for Insert & Delete record using
Stored Procedures….

Stored Procedure For Inserting & Deleting
Record:

Stored Procedures For Create and
drop:

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