1. .NET Data Access and Manipulation
ADO.NET
.NET Data Access and Manipulation

2. Overview What is ADO.NET?
Disconnected vs. connected data access models
ADO.NET Architecture
ADO.NET Core Objects
Steps of Data Access
Advanced Techniques and UI Tools

3. What is ADO.NET?
ADO.NET is an object-oriented set of libraries that allows you to interact with data sources. Commonly, the data source is a database, but it could also be a text file, an Excel spreadsheet, or an XML file
A data-access technology that enables applications to connect to data stores and manipulate data contained in them in various ways
ADO.NET is a data access technology from Microsoft .Net Framework , which provides communication between relational and non-relational systems through a common set of components 

4. What is ADO.NET?
An object oriented framework that allows you to interact with database systems

5. Objective of ADO.NET Support disconnected data architecture,
Tight integration with XML,
Common data representation
Ability to combine data from multiple and varied data sources
Optimized facilities for interacting with a database

6. ADO.NET Architecture

7. ADO.NET Core Objects Core namespace: System.Data
.NET Framework data providers:
Data Provider
Namespace
Data Source Description
SQL Server
System.Data.SqlClient
For interacting with Microsoft SQL Server.
OLE DB
System.Data.OleDb
Data Sources that expose an OleDb interface, i.e. Access or Excel.
ODBC
System.Data.Odbc
Data Sources with an ODBC interface. Normally older data bases.
Oracle
System.Data.OracleClient
For Oracle Databases.

8. ADO.NET Core Objects Object Description Connection
Establishes a connection to a specific data source. (Base class: DbConnection)
Command
Executes a command against a data source. Exposes Parameters and can execute within the scope of a Transaction from a Connection. (The base class: DbCommand)
DataReader
Reads a forward-only, read-only stream of data from a data source. (Base class: DbDataReader)
DataAdapter
Populates a DataSet and resolves updates with the data source. (Base class: DbDataAdapter)
DataTable
Has a collection of DataRows and DataColumns representing table data, used in disconnected model
DataSet
Represents a cache of data. Consists of a set of DataTables and relations among them

9. Connected Data Access Model

10. Disconnected Data Access Model

11. Pros and Cons - + Connected Disconnected Database Resources
Network Traffic
Memory Usage
Data Access

12. Connected MODEL

13. Steps of Data Acces : Connected Environment
Create connection
Create command (select-insert-update-delete)
Open connection
If SELECT -> use a DataReader to fetch data
If UPDATE,DELETE, INSERT -> use command object’s methods
Close connection

14. The SqlConnection Object
Creating Sql Connection
SqlConnection conn = new SqlConnection( "Data Source=(local);Initial Catalog=Northwind;Integrated Security=SSPI");
SqlConnection conn = new SqlConnection("Data Source=DatabaseServer;Initial Catalog=Northwind;User ID=YourUserID;Password=YourPassword");
Connection String Parameter Name
Description
Data Source
Identifies the server. Could be local machine, machine domain name, or IP Address.
Initial Catalog
Database name.
Integrated Security
Set to SSPI (Security Support Provider Interface)to make connection with user’s Windows login
User ID
Name of user configured in SQL Server.
Password
Password matching SQL Server User ID.

15. SqlDataReader rdr = cmd.ExecuteReader();
The SqlCommand Object
A SqlCommand object allows you to specify what type of interaction you want to perform with a database. For example, you can do select, insert, modify, and delete commands on rows of data in a database table. The SqlCommand object can be used to support disconnected data management scenarios
SqlCommand cmd = new SqlCommand("select CategoryName from Categories", conn);
Querying Data
When using a SQL select command, you retrieve a data set for viewing. To accomplish this with a SqlCommand object, you would use the ExecuteReader method, which returns a SqlDataReader object.
SqlDataReader rdr = cmd.ExecuteReader();

16. SQL COmmand Inserting Data
To insert data into a database, use the ExecuteNonQuery method of the SqlCommand object.
string insertString insert into Categories (CategoryName, Description)
values ('Miscellaneous', 'Whatever doesn''t fit elsewhere')";
// 1. Instantiate a new command with a query and connection
SqlCommand cmd = new SqlCommand(insertString, conn);
// 2. Call ExecuteNonQuery to send command
cmd.ExecuteNonQuery();

17. SQL COmmand Updating Data
The ExecuteNonQuery method is also used for updating data
// prepare command string
string updateString update Categories set CategoryName = 'Other'
where CategoryName = 'Miscellaneous'";
// 1. Instantiate a new command with command text only
SqlCommand cmd = new SqlCommand(updateString);
// 2. Set the Connection property
cmd.Connection = conn;
// 3. Call ExecuteNonQuery to send command
cmd.ExecuteNonQuery();

18. SQL Command Getting Single values
Sometimes all you need from a database is a single value, which could be a count, sum, average, or other aggregated value from a data set.
The following example shows how to do this with the executeScalar method
// 1. Instantiate a new command
SqlCommand cmd = new SqlCommand("select count(*) from Categories", conn);
// 2. Call ExecuteNonQuery to send command
int count = (int)cmd.ExecuteScalar();

19. SQL Command
FOR XML AUTO — Builds a tree based on the tables in the FROM clause
FOR XML RAW — Maps result set rows to elements with columns mapped to attributes
FOR XML EXPLICIT — Requires that you specify the shape of the XML tree to be returned
static void ExecuteXmlReader() {
string select = "SELECT ContactName,CompanyName " +"FROM Customers FOR XML AUTO";
SqlConnection conn = new SqlConnection(GetDatabaseConnection());
conn.Open();
SqlCommand cmd = new SqlCommand(select, conn);
XmlReader xr = cmd.ExecuteXmlReader();
xr.Read();
string data; do
data = xr.ReadOuterXml();
if (!string.IsNullOrEmpty(data))
Console.WriteLine(data);
} while (!string.IsNullOrEmpty(data));
conn.Close(); }

20. Reading Data with the SqlDataReader
A SqlDataReader is a type that is good for reading data in the most efficient manner possible. You can *not* use it for writing data.
You can read from SqlDataReader objects in a forward-only sequential manner. Once you’ve read some data, you must save it because you will not be able to go back and read it again.
Creating a SqlDataReader Object
SqlDataReader rdr = cmd.ExecuteReader();
Reading Data
while (rdr.Read()) {
// get the results of each column
string contact = (string)rdr["ContactName"];
string company = (string)rdr["CompanyName"];
string city = (string)rdr["City"];
// print out the results
Console.Write("{0,-25}", contact);
Console.Write("{0,-20}", city);
Console.Write("{0,-25}", company);
Console.WriteLine(); }

21. EXAMPLE static void Main() { string connectionString =
Properties.Settings.Default.connStr;
string queryString = "SELECT CategoryID, CategoryName FROM dbo.Categories;";
SqlConnection connection = new SqlConnection(connectionString);
SqlCommand command = new SqlCommand(queryString,connection);
try
connection.Open();
SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
Console.WriteLine("\t{0}\t{1}“,reader[0],reader[1]); }
reader.Close();
connection.close();
catch (Exception ex)
Console.WriteLine(ex.Message);
EXAMPLE

22. Stored Procedures
A stored procedures is a pre-defined, reusable routine that is stored in a database.
SQL Server compiles stored procedures, which makes them more efficient to use.
Therefore, rather than dynamically building queries in your code, you can take advantage of the reuse and performance benefits of stored procedures.
let the SqlCommand object know which stored procedure to execute and tell the SqlCommand object that it is executing a stored procedure. These two steps are shown below:
// 1. create a command object identifying the stored procedure
SqlCommand cmd = new SqlCommand("Ten Most Expensive Products", conn);
// 2. set the command object so it knows to execute a stored procedure
cmd.CommandType = CommandType.StoredProcedure;

23. Type the following in SQL Query Analyzer:
Start->Programs->Microsoft SQL Server->Query Analyzer
CREATE PROCEDURE EmployeeId NCHAR(25)) AS
SET NOCOUNT ON
UPDATE Employees
SET WHERE
C# Program:
SqlConnection con=new SqlConnection(“---”);
con.open();
SqlCommand scmd=CommandType.StoredProcedure;
Scmd.Prameters.Add(new
Scmd.Prameters.Add(new
Scmd.UpdatedRowSource=UpdatedRowSource.None;
Scmd.Parameters[0].Value=999;
Scmd.Parameters[1].Value=“Raja”;
Scmd.ExecuteNonQuery();
String s=scmd.Parameters[1].Value.ToString();
Messagebox.Show(s);

24. Disconnected Model

25. DataSet
A DataSet is an in-memory data store that can hold numerous tables.
DataSets only hold data and do not interact with a data source.
This is a collection of DataTables
. We use the DataSet type to store many DataTables in a single collection.
Conceptually, the DataSet acts as a set of DataTable instances.
The SqlDataAdapter that manages connections with the data source and gives us disconnected behavior

26. Steps Creating a DataSet Object
DataSet dsCustomers = new DataSet();
The DataSet constructor doesn’t require parameters. However there is one overload that accepts a string for the name of the DataSet, which is used if you were to serialize the data to XML.
Creating A SqlDataAdapter
The SqlDataAdapter holds the SQL commands and connection object for reading and writing data
SqlDataAdapter daCustomers = new SqlDataAdapter("select CustomerID, CompanyName from Customers", conn);
The SQL select statement specifies what data will be read into a DataSet.
The connection object, conn, should have already been instantiated, but not opened. It is the SqlDataAdapter’s responsibility to open and close the connection during Fill and Update method calls.

27. Steps SqlCommandBuilder:
There are two ways to add insert, update, and delete commands: via SqlDataAdapter properties or with a SqlCommandBuilder.
Here’s how to add commands to the SqlDataAdapter with the SqlCommandBuilder
SqlCommandBuilder cmdBldr = new SqlCommandBuilder(daCustomers);
This tells the SqlCommandBuilder what SqlDataAdapter to add commands to
Filling the DataSet
Once you have a DataSet and SqlDataAdapter instances, you need to fill the DataSet.
daCustomers.Fill(dsCustomers, "Customers");
The Fill method, in the code above, takes two parameters: a DataSet and a table name. The DataSet must be instantiated before trying to fill it with data. The second parameter is the name of the table that will be created in the DataSet. You can name the table anything you want. Its purpose is so you can identify the table with a meaningful name later on. Typically, I’ll give it the same name as the database table.

28. Disconnected – Update, Delete, Insert
SqlDataAdapter da = new SqlDataAdapter();
DataSet ds = new DataSet();
SqlCommandBuilder cmdBuilder = new SqlCommandBuilder(da);
da.Fill(ds);
INITIAL CODE
DataRow dr = ds.Tables[0].Rows[0];
dr.Delete();
da.UpdateCommand = builder.GetUpdateCommand();
da.Update(ds);
DELETE
DataRow dr = ds.Tables[0].Rows[0];
dr["CustomerName"] = "John";
da.UpdateCommand = builder.GetUpdateCommand();
da.Update(ds);
UPDATE
DataRow dr = ds.Tables[0].NewRow();
dr["CustomerName"] = "John";
dr["CustomerSurName"] = "Smith";
ds.Tables[0].Rows.Add(dr);
da.UpdateCommand = builder.GetUpdateCommand();
da.Update(ds);
INSERT

29. EXAMPLE using System; using System.Data; using System.Data.SqlClient;
namespace SampleClass {
class Program
static void Main(string[] args)
string connStr =
Properties.Settings.Default.connStr;
SqlConnection conn = new SqlConnection(connStr);
string queryString = "SELECT * from titles;";
SqlDataAdapter da = new
SqlDataAdapter(queryString,conn);
DataSet ds = new DataSet();
da.fill(ds);
// Work on the data in memory using
// the DataSet (ds) object }
EXAMPLE

30. Choosing a DataReader or a Dataset
The type of functionality application requires should be considered
Use a dataset to:
Cache data locally in your application so that you can manipulate it
Remote data between tiers or from an XML Web service
Interact with data dynamically such as binding to a Windows Forms control or combining and relating data from multiple sources
Perform extensive processing on data without requiring an open connection to the data source, which frees the connection to be used by other clients
If readonly data is needed use DataReader to boost performance

31. Best Practices
Don’t create a new connection string for every code connecting to DB
Use app.config file to keep your connection strings through the application scope
Right click on project and select properties
Select settings from the left tabbed menu
add the connection string to the table and save project, Name field is the name of the string to access at runtime
Accessing settings at runtime:
string connStr = Properties.Settings.Default.connStr;
You can keep any other variable to reach at runtime using this technique

32. Data binding
It provide the way to link the contents of a control with a data source.
Simple Binding:Controls that contain one value, such as label or text box
Complex Binding: Controls populated with rows of data, such as list box, data grid
Simple Data Binding:
DataBinding.Add(Control Propertey, Data Source,Data Member);
Program:
Textbox1.DataBindings.Add(“Text”,ds,”Employes.EmployeeID”);
Textbox2.DataBindings.Add(“Text”,ds,”Employes.Name”);
Complex Data Binding:
Two Properties: DataSource, Display Member
Sda.Fill(ds,”Employees”);
DataTable dt=ds.Tables[0];
ListBox.DataSource=ds;
Listbox.DisplayMember=“Employees.FirstName”;

33. using System; using System. Drawing; using System
using System; using System.Drawing; using System.Collections; using System.ComponentModel; using System.Windows.Forms; using System.Data; using System.Data.SqlClient; public class Form1 : System.Windows.Forms.Form { private System.Windows.Forms.TextBox textBox1; private System.Windows.Forms.TextBox textBox2; private System.Windows.Forms.Button buttonBack; private System.Windows.Forms.Button buttonNext; private System.Data.DataSet dataSet1; private System.ComponentModel.Container components = null; private BindingManagerBase bMgr;

34. public Form1() { InitializeComponent(); } private void InitializeComponent() { this.textBox1 = new System.Windows.Forms.TextBox(); this.textBox2 = new System.Windows.Forms.TextBox(); this.buttonBack = new System.Windows.Forms.Button(); this.buttonNext = new System.Windows.Forms.Button(); this.dataSet1 = new System.Data.DataSet(); ((System.ComponentModel.ISupportInitialize)(this.dataSet1)).BeginIn it(); this.SuspendLayout(); this.textBox1.Location = new System.Drawing.Point(8, 8); this.textBox1.Name = "textBox1"; this.textBox1.Size = new System.Drawing.Size(160, 20); this.textBox1.TabIndex = 0;

35. this. textBox1. Text = "textBox1"; this. textBox2
this.textBox1.Text = "textBox1"; this.textBox2.Location = new System.Drawing.Point(8, 40); this.textBox2.Name = "textBox2"; this.textBox2.Size = new System.Drawing.Size(160, 20); this.textBox2.TabIndex = 1; this.textBox2.Text = "textBox2"; this.buttonBack.Location = new System.Drawing.Point(24, 80); this.buttonBack.Name = "buttonBack"; this.buttonBack.Size = new System.Drawing.Size(56, 23); this.buttonBack.TabIndex = 2; this.buttonBack.Text = "<< Back"; this.buttonBack.Click += new System.EventHandler(this.buttonBack_Click); this.buttonNext.Location = new System.Drawing.Point(96, 80); this.buttonNext.Name = "buttonNext"; this.buttonNext.Size = new System.Drawing.Size(56, 23);

36. this. buttonNext. TabIndex = 3; this. buttonNext
this.buttonNext.TabIndex = 3; this.buttonNext.Text = "Next>>"; this.buttonNext.Click += new System.EventHandler(this.buttonNext_Click); this.dataSet1.DataSetName = "NewDataSet"; this.dataSet1.Locale = new System.Globalization.CultureInfo("en-US"); this.AutoScaleBaseSize = new System.Drawing.Size(5, 13); this.ClientSize = new System.Drawing.Size(176, 108); this.Controls.Add(this.buttonNext); this.Controls.Add(this.buttonBack); this.Controls.Add(this.textBox2); this.Controls.Add(this.textBox1); this.Name = "Form1"; this.Text = "Form1"; this.Load += new System.EventHandler(this.Form1_Load);

37. ((System. ComponentModel. ISupportInitialize)(this. dataSet1))
((System.ComponentModel.ISupportInitialize)(this.dataSet1)).EndInit (); this.ResumeLayout(false); } static void Main() { Application.Run(new Form1()); private void Form1_Load(object sender, System.EventArgs e) { string connString = "server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI"; string sql * from employee "; SqlConnection conn = new SqlConnection(connString); SqlDataAdapter da = new SqlDataAdapter(sql, conn); da.Fill(dataSet1, "employee"); textBox1.DataBindings.Add("text", dataSet1, "employee.firstname");

38. textBox2. DataBindings. Add("text", dataSet1, "employee
textBox2.DataBindings.Add("text", dataSet1, "employee.lastname"); bMgr = this.BindingContext[dataSet1, "employee"]; } private void buttonNext_Click(object sender, System.EventArgs e) { bMgr.Position += 1; private void buttonBack_Click(object sender, System.EventArgs e) { bMgr.Position -= 1;