Database ADO.net

Populate a DataSet with multiple DataTable objects using multiple SELECT statements

Posted on by coder 
   


using System;
using System.Data;
using System.Data.SqlClient;

class MultipleDataTables
{
  public static void Main()
  {
    SqlConnection mySqlConnection =new SqlConnection("server=(local)SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");

    SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
    mySqlCommand.CommandText =
      "SELECT TOP 2 ID, FirstName, LastName " +
      "FROM Employee " +
      "ORDER BY ID;" +
      "SELECT ID, LastName " +
      "FROM MyEmployee " +
      "WHERE ID = 9;";

    SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
    mySqlDataAdapter.SelectCommand = mySqlCommand;
    DataSet myDataSet = new DataSet();
    mySqlConnection.Open();
    int numberOfRows = mySqlDataAdapter.Fill(myDataSet);
    Console.WriteLine("numberOfRows = " + numberOfRows);
    mySqlConnection.Close();

    myDataSet.Tables["Table"].TableName = "Employee";
    myDataSet.Tables["Table1"].TableName = "MyEmployee";

    foreach (DataTable myDataTable in myDataSet.Tables) {
      Console.WriteLine("
Reading from the " +
        myDataTable.TableName + "DataTable");
      foreach (DataRow myDataRow in myDataTable.Rows)
      {
        foreach (DataColumn myDataColumn in myDataTable.Columns)
        {
          Console.WriteLine(myDataColumn + "= " +
            myDataRow[myDataColumn]);
        }
      }
    }
  }
}

Populate a DataSet object with multiple DataTable objects

Posted on by coder 
   

using System;
using System.Data;
using System.Data.SqlClient;

class MultipleDataTables2
{
  public static void Main()
  {
    SqlConnection mySqlConnection =new SqlConnection("server=(local)SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");

    SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
    mySqlCommand.CommandText =
      "SELECT TOP 2 ID, FirstName, LastName " +
      "FROM Employee " +
      "ORDER BY ID";
    SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
    mySqlDataAdapter.SelectCommand = mySqlCommand;
    DataSet myDataSet = new DataSet();
    mySqlConnection.Open();
    int numberOfRows = mySqlDataAdapter.Fill(myDataSet, "Employee");
    Console.WriteLine("numberOfRows = " + numberOfRows);

    mySqlDataAdapter.SelectCommand.CommandText =
      "SELECT ID, Name " +
      "FROM Customers " +
      "WHERE ID = '001'";
    numberOfRows = mySqlDataAdapter.Fill(myDataSet, "Customers");
    Console.WriteLine("numberOfRows = " + numberOfRows);

    mySqlConnection.Close();

    foreach (DataTable myDataTable in myDataSet.Tables) {
      Console.WriteLine("
Reading from the " +
        myDataTable.TableName + "DataTable");
      foreach (DataRow myDataRow in myDataTable.Rows)
      {
        foreach (DataColumn myDataColumn in myDataTable.Columns)
        {
          Console.WriteLine(myDataColumn + "= " +
            myDataRow[myDataColumn]);
        }
      }
    }
  }
}

Populate a DataSet object using a SELECT statement

Posted on by coder 
   
 

using System;
using System.Data;
using System.Data.SqlClient;

class PopulateDataSetUsingSelect {
    public static void Main() {
        SqlConnection mySqlConnection = new SqlConnection("server=localhost;database=Northwind;uid=sa;pwd=sa");
        SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
        mySqlCommand.CommandText =
          "SELECT TOP 5 ProductID, ProductName, UnitPrice " +
          "FROM Products " +
          "ORDER BY ProductID";
        SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
        mySqlDataAdapter.SelectCommand = mySqlCommand;
        DataSet myDataSet = new DataSet();
        mySqlConnection.Open();
        Console.WriteLine("Retrieving rows from the Products table");
        int numberOfRows = mySqlDataAdapter.Fill(myDataSet, "Products");
        Console.WriteLine("numberOfRows = " + numberOfRows);
        mySqlConnection.Close();
        DataTable myDataTable = myDataSet.Tables["Products"];
        foreach (DataRow myDataRow in myDataTable.Rows) {
            Console.WriteLine("ProductID = " + myDataRow["ProductID"]);
            Console.WriteLine("ProductName = " + myDataRow["ProductName"]);
            Console.WriteLine("UnitPrice = " + myDataRow["UnitPrice"]);
        }
    }
}

How to perform a SELECT statement and store the returned rows in a DataSet object

Posted on by coder 


   


using System;
using System.Data;
using System.Data.SqlClient;

class SelectIntoDataSet {
  public static void Main() {
    string connectionString = "server=(local)SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI";

    SqlConnection mySqlConnection = new SqlConnection(connectionString);

    string selectString = "SELECT TOP 10 ID, FirstName, LastName FROM Employee ORDER BY ID";

    SqlCommand mySqlCommand = mySqlConnection.CreateCommand();

    mySqlCommand.CommandText = selectString;

    SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();

    mySqlDataAdapter.SelectCommand = mySqlCommand;
    DataSet myDataSet = new DataSet();

    mySqlConnection.Open();

    Console.WriteLine("Retrieving rows from the Employee table");
    mySqlDataAdapter.Fill(myDataSet, "Employee");

    mySqlConnection.Close();

    DataTable myDataTable = myDataSet.Tables["Employee"];

    foreach (DataRow myDataRow in myDataTable.Rows)
    {
      Console.WriteLine("ID = "+ myDataRow["ID"]);
      Console.WriteLine("FirstName = "+ myDataRow["FirstName"]);
      Console.WriteLine("LastName = "+ myDataRow["LastName"]);
    }
  }
}

Finding Data

Posted on by coder 
   




using System;
using System.Data;
using System.Data.SqlClient; 
using System.Collections.Generic;
using System.Text;

class Program {
    static void Main(string[] args) {
        SqlConnection thisConnection = new SqlConnection(
             @"Server=(local)sqlexpress;Integrated Security=True;" +
             "Database=northwind");
        SqlDataAdapter thisAdapter = new SqlDataAdapter("SELECT CustomerID, CompanyName FROM Customers", thisConnection);
        SqlCommandBuilder thisBuilder = new SqlCommandBuilder(thisAdapter);

        DataSet thisDataSet = new DataSet();
        thisAdapter.Fill(thisDataSet, "Customers");
        Console.WriteLine("# rows before change: {0}",thisDataSet.Tables["Customers"].Rows.Count);

        DataColumn[] keys = new DataColumn[1];
        keys[0] = thisDataSet.Tables["Customers"].Columns["CustomerID"];
        thisDataSet.Tables["Customers"].PrimaryKey = keys;

        DataRow findRow = thisDataSet.Tables["Customers"].Rows.Find("AAA");

        if (findRow == null) {
            DataRow thisRow = thisDataSet.Tables["Customers"].NewRow();
            thisRow["CustomerID"] = "AAA";
            thisRow["CompanyName"] = "AAA Ltd.";
            thisDataSet.Tables["Customers"].Rows.Add(thisRow);
            if ((findRow = thisDataSet.Tables["Customers"].Rows.Find("AAA")) != null) {
                Console.WriteLine("added");
            }
        } else {
            Console.WriteLine("AAA already present in database");
        }
        thisAdapter.Update(thisDataSet, "Customers");
        Console.WriteLine("# rows after change: {0}",thisDataSet.Tables["Customers"].Rows.Count);
        thisConnection.Close();
    }
}

Print DataSet out

Posted on by coder

using System;
using System.Collections.Generic;
using System.Text;

using System.Data;
using System.Data.SqlClient;
using System.Data.Common;

class Program {
static void Main(string[] args) {
string cnStr = “uid=sa;pwd=;Initial Catalog=yourDatabase;Data Source=(local)”;
DataSet myDS = new DataSet(“Cars”);
SqlDataAdapter dAdapt = new SqlDataAdapter(“Select * From Inventory”, cnStr);
DataTableMapping custMap = dAdapt.TableMappings.Add(“Inventory”, “Current Inventory”);
custMap.ColumnMappings.Add(“CarID”, “Car ID”);
custMap.ColumnMappings.Add(“PetName”, “Name of Car”);

try {
dAdapt.Fill(myDS, “Inventory”);
} catch (Exception ex) {
Console.WriteLine(ex.Message);
}
PrintDataSet(myDS);
}
static void PrintDataSet(DataSet ds) {
Console.WriteLine(“Tables in '{0}' DataSet.
“, ds.DataSetName);
foreach (DataTable dt in ds.Tables) {
Console.WriteLine(“{0} Table.
“, dt.TableName);
for (int curCol = 0; curCol < dt.Columns.Count; curCol++) { Console.Write(dt.Columns[curCol].ColumnName.Trim() + " "); } for (int curRow = 0; curRow < dt.Rows.Count; curRow++) { for (int curCol = 0; curCol < dt.Columns.Count; curCol++) { Console.Write(dt.Rows[curRow][curCol].ToString().Trim() + " "); } Console.WriteLine(); } } } } [/csharp]

The use of the Find() and FindRows() methods of a DataView to find DataRowView objects

Posted on by coder

using System;
using System.Data;
using System.Data.SqlClient;

class FindingDataRowViews
{
public static void Main()
{
SqlConnection mySqlConnection =new SqlConnection(“server=(local)SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;”);
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.CommandText =
“SELECT ID, FirstName, LastName ” +
“FROM Employee”;
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
mySqlDataAdapter.SelectCommand = mySqlCommand;
DataSet myDataSet = new DataSet();
mySqlConnection.Open();
mySqlDataAdapter.Fill(myDataSet, “Employee”);
mySqlConnection.Close();
DataTable employeeDT = myDataSet.Tables[“Employee”];

string filterExpression = “ID = 9”;
string sortExpression = “ID”;
DataViewRowState rowStateFilter = DataViewRowState.OriginalRows;

DataView employeeDV = new DataView();
employeeDV.Table = employeeDT;
employeeDV.RowFilter = filterExpression;
employeeDV.Sort = sortExpression;
employeeDV.RowStateFilter = rowStateFilter;

foreach (DataRowView myDataRowView in employeeDV)
{
for (int count = 0; count < employeeDV.Table.Columns.Count; count++) { Console.WriteLine(myDataRowView[count]); } Console.WriteLine(""); } int index = employeeDV.Find("8"); Console.WriteLine("8 found at index " + index + " "); DataRowView[] employeeDRVs = employeeDV.FindRows("8"); foreach (DataRowView myDataRowView in employeeDRVs) { for (int count = 0; count < employeeDV.Table.Columns.Count; count++) { Console.WriteLine(myDataRowView[count]); } Console.WriteLine(""); } } } [/csharp]