/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy
Publisher: Sybex;
ISBN: 0782129110
*/
/*
Example23_2.cs illustrates how to perform INSERT, UPDATE,
and DELETE statements using ADO.NET
*/
using System;
using System.Data;
using System.Data.SqlClient;
public class Example23_2
{
public static void DisplayDataTable(
SqlDataAdapter mySqlDataAdapter,
DataSet myDataSet,
DataTable myDataTable
)
{
// use the Clear() method of the DataSet object
// to remove all the rows in the DataSet
myDataSet.Clear();
// use the Fill() method of the SqlDataAdapter object
// to synchronize any changes made to the database
// with the DataSet object
mySqlDataAdapter.Fill(myDataSet, "Customers");
// display the columns for each row in the DataTable,
// using a DataRow object to access each row in the DataTable
foreach (DataRow myDataRow in myDataTable.Rows)
{
Console.WriteLine("CustomerID = " + myDataRow["CustomerID"]);
Console.WriteLine("CompanyName = " + myDataRow["CompanyName"]);
Console.WriteLine("ContactName = " + myDataRow["ContactName"]);
Console.WriteLine("Address = " + myDataRow["Address"]);
}
}
public static void AddRow(
SqlConnection mySqlConnection,
SqlDataAdapter mySqlDataAdapter,
DataSet myDataSet
)
{
Console.WriteLine("\nAdding a new row with CustomerID of 'T1COM'");
// step 1: formulate a string containing the SQL statement
string insertString =
"INSERT INTO Customers (" +
" CustomerID, CompanyName, ContactName, Address" +
") VALUES (" +
" @CustomerID, @CompanyName, @ContactName, @Address" +
")";
// step 2: create a SqlCommand object to hold the SQL statement
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
// step 3: set the CommandText property of the SqlCommand object to
// the SQL string
mySqlCommand.CommandText = insertString;
// step 4: use the Add() method through the Parameters property
// of the SqlCommand object to add the parameters to the SqlCommand
// object
mySqlCommand.Parameters.Add("@CustomerID", SqlDbType.NChar, 5);
mySqlCommand.Parameters.Add("@CompanyName", SqlDbType.NVarChar, 40);
mySqlCommand.Parameters.Add("@ContactName", SqlDbType.NVarChar, 30);
mySqlCommand.Parameters.Add("@Address", SqlDbType.NVarChar, 60);
// step 5: set the parameters to specified values using the
// Value property
mySqlCommand.Parameters["@CustomerID"].Value = "T1COM";
mySqlCommand.Parameters["@CompanyName"].Value = "T1 Company";
mySqlCommand.Parameters["@ContactName"].Value = "Jason Price";
mySqlCommand.Parameters["@Address"].Value = "1 Main Street";
// step 6: use the ExecuteNonQuery() method to run the
// SQL statement
mySqlCommand.ExecuteNonQuery();
}
public static void ModifyRow(
SqlConnection mySqlConnection,
SqlDataAdapter mySqlDataAdapter,
DataSet myDataSet
)
{
Console.WriteLine("\nModifying the new row");
// step 1: formulate the SQL statement
string updateString =
"UPDATE Customers " +
"SET " +
" CompanyName = @CompanyName, " +
" ContactName = @ContactName, " +
" Address = @Address " +
"WHERE CustomerID = @CustomerID";
// step 2: create a SqlCommand object to hold the SQL statement
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
// step 3: set the CommandText property of the SqlCommand object to
// the SQL string
mySqlCommand.CommandText = updateString;
// step 4: use the Add() method through the Parameters property
// to add the parameters
mySqlCommand.Parameters.Add("@CustomerID", SqlDbType.NChar, 5);
mySqlCommand.Parameters.Add("@CompanyName", SqlDbType.NVarChar, 40);
mySqlCommand.Parameters.Add("@ContactName", SqlDbType.NVarChar, 30);
mySqlCommand.Parameters.Add("@Address", SqlDbType.NVarChar, 60);
// step 5: set the parameters to values using the Value property
mySqlCommand.Parameters["@CustomerID"].Value = "T1COM";
mySqlCommand.Parameters["@CompanyName"].Value = "Widgets Inc.";
mySqlCommand.Parameters["@ContactName"].Value = "John Smith";
mySqlCommand.Parameters["@Address"].Value = "1 Any Street";
// step 6: use the ExecuteNonQuery() method to run the
// SQL statement
mySqlCommand.ExecuteNonQuery();
}
public static void RemoveRow(
SqlConnection mySqlConnection,
SqlDataAdapter mySqlDataAdapter,
DataSet myDataSet
)
{
Console.WriteLine("\nRemoving the new row");
// step 1: formulate the SQL statement
string deleteString =
"DELETE FROM Customers " +
"WHERE CustomerID = @CustomerID";
// step 2: create a SqlCommand object to hold the SQL statement
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
// step 3: set the CommandText property of the SqlCommand object to
// the SQL string
mySqlCommand.CommandText = deleteString;
// step 4: use the Add() method through the Parameters property
// to add the parameter
mySqlCommand.Parameters.Add("@CustomerID", SqlDbType.NChar, 5);
// step 5: set the parameters to values using the Value property
mySqlCommand.Parameters["@CustomerID"].Value = "T1COM";
// step 6: use the ExecuteNonQuery() method to run the
// SQL statement
mySqlCommand.ExecuteNonQuery();
}
public static void Main()
{
// formulate a string containing the details of the
// database connection
string connectionString =
"server=localhost;database=Northwind;uid=sa;pwd=sa";
// create a SqlConnection object to connect to the
// database, passing the connection string to the constructor
SqlConnection mySqlConnection =
new SqlConnection(connectionString);
// formulate a SELECT statement to retrieve the
// CustomerID, CompanyName, ContactName, and Address
// columns for rows from the Customers table
string selectString =
"SELECT CustomerID, CompanyName, ContactName, Address " +
"FROM Customers " +
"WHERE CustomerID IN ('ALFKI', 'T1COM')";
// create a SqlCommand object to hold the SELECT statement
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
// set the CommandText property of the SqlCommand object to
// the SELECT string
mySqlCommand.CommandText = selectString;
// create a SqlDataAdapter object
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
// set the SelectCommand property of the SqlAdapter object
// to the SqlCommand object
mySqlDataAdapter.SelectCommand = mySqlCommand;
// create a DataSet object to store the results of
// the SELECT statement
DataSet myDataSet = new DataSet();
// open the database connection using the
// Open() method of the SqlConnection object
mySqlConnection.Open();
// use the Fill() method of the SqlDataAdapter object to
// retrieve the rows from the table, storing the rows locally
// in a DataTable of the DataSet object
string dataTableName = "Customers";
Console.WriteLine("Retrieving a row from the Customers table");
mySqlDataAdapter.Fill(myDataSet, dataTableName);
// get the DataTable object from the DataSet object
DataTable myDataTable = myDataSet.Tables[dataTableName];
// display the rows in the DataTable object
DisplayDataTable(mySqlDataAdapter, myDataSet, myDataTable);
// add a new row
AddRow(mySqlConnection, mySqlDataAdapter, myDataSet);
DisplayDataTable(mySqlDataAdapter, myDataSet, myDataTable);
// modify the new row
ModifyRow(mySqlConnection, mySqlDataAdapter, myDataSet);
DisplayDataTable(mySqlDataAdapter, myDataSet, myDataTable);
// remove the new row
RemoveRow(mySqlConnection, mySqlDataAdapter, myDataSet);
DisplayDataTable(mySqlDataAdapter, myDataSet, myDataTable);
// close the database connection using the Close() method
// of the SqlConnection object
mySqlConnection.Close();
}
}