Introduction
Accessing database is pretty simple job using C# and ADO. In this article, the sample gives you the guidelines for a C# programmer which demonstrates how to use ADO.NET objects including ADOCOnnection, ADOCommand, ADODataReader. Microsoft Data Access Technology got changed with the ADO.NET I access database Employee.mdb, which has a table called "Employee". I will add the employee information to the database .
Using the Code
To write a code in ADO you need to use the following at the beginning of your code.
using System;
using System.Drawing;
using System.ComponentModel;
using System.WinForms;
using System.Data.ADO ;
using System.Data ;
using System.Threading ;
Proceeding with the next step, make sure that all of your GUI is in place for adding the data ( all the text boxes and labels , that is pretty simple so I am not going to cover this), Next will will go ahead and get the connection to the database( note the connection to the database should be running on a different thread, so that it will not mess up the GUI. to do this we have to start a thread as shown below.
ThreadStart DBThread = new ThreadStart(ConnectToDatabase) ;
Thread DB = new Thread(DBThread) ;
DB.Start() ;
As you can see above we have successfully started the thread, This thread calls the method ConnectToDataBase, let see what this ConnectToDatabase method is all about.
public void ConnectToDatabase()
{
Infobar.Text="Please Wait, Connecting to database...." ;
string conn=
"Provider=Microsoft.Jet.OLEDB.4.0 ;Data Source=Employee.mdb" ;
ADOConnection dbConn = new ADOConnection(conn) ;
string empStr = "Select id from Employee" ;
ADOCommand sqlCommand =new ADOCommand(empStr,dbConn);
dbConn.Open();
ADODataReader reader;
sqlCommand.Execute(out reader) ;
int numRecords=0 ;
while(reader.Read())
{
numRecords++ ;
}
numRecords++ ;
employeeID.Text = numRecords.ToString() ;
Infobar.Text="Connected - Now you can Add records";
}
Hope the above code is not much confusing, It is lot simpler than writing the code in VC++ ADO. now it's time to write a method that actually takes all the parameters from the GUI Form and writes it to the database with the click of a button. for this we will create a button called
Add In your
InitializeComponents Method the code would look like this
Add.Text = "AddToDatabase";
Add.Click += new System.EventHandler(WriteToDataBase);
This gets as simple as it looks, Actually writing to database is much simpler as shown below in the code.
protected void WriteToDatabase(object sender, System.EventArgs e)
{
if(employeeID.Text!=""&&employeeLastName.Text!=""
&&employeeFirstName.Text!=""&&employeeAge.Text!=""
&&employeeSSN.Text!="")
{
string conn="Provider=Microsoft.Jet.OLEDB.4.0 ;"+
"Data Source=Employee.mdb" ;
ADOConnection dbConn = new ADOConnection(conn) ;
dbConn.Open();
string strInsert = "INSERT INTO Employee (employeeID, " +
"employeeLastName, employeeFirstName, "+
"employeeAge, employeeSSN) VALUES ( "
+employeeID.Text+", '"
+employeeLastName.Text+"' , '"
+employeeFirstName.Text+"' , "
+employeeAge.Text+", "
+employeeSSN.Text+")";
ADOCommand adoInsert = new ADOCommand(strInsert,DBConn) ;
adoInsert.ExecuteNonQuery() ;
Infobar.Text="Data is being Added to Database " ;
int iClear=int.Parse(employeeID.Text);
iClear++;
employeeID.Text=i.ToString() ;
employeeLastName.Text="" ;
employeeFirstName.Text="" ;
employeeAge.Text="" ;
employeeSSN.Text="" ;
Infobar.Text="Connected - Now you can Add more records...";
DBConn.Close() ;
}
else
{
MessageBox.Show("All fields must be filled.", "Error",
MessageBox.IconExclamation);
}
}
Hope this was helpful. Will write more on how to view the database values and how to delete those values in my coming articles.
General 
News 
Question 
Answer 
Joke 
Rant 
Admin 
to do in c#, can any one let me know with code example ...
