Get specified column data type and column name from OleDbSchemaTable


   

using System;
using System.Data;
using System.Data.OleDb;

public class DatabaseInfo {    
 public static void Main () { 
   String connect = "Provider=Microsoft.JET.OLEDB.4.0;data source=.Employee.mdb";
   OleDbConnection con = new OleDbConnection(connect);
   con.Open();  
   Console.WriteLine("Made the connection to the database");

   Console.WriteLine("Information for each table contains:");
   DataTable tables = con.GetOleDbSchemaTable(OleDbSchemaGuid.Tables,new object[]{null,null,null,"TABLE"});

   DataTable cols = con.GetOleDbSchemaTable(OleDbSchemaGuid.Columns,
         new object[]{null,null,"Employee",null});

   Console.WriteLine("The columns in the Customer table are:");
 
   foreach(DataRow row in cols.Rows) 
     Console.WriteLine("  {0}	{1}", row[3],(OleDbType)row[11]);

   con.Close();
 }
}
 

           
          


Get all table names


   


using System;
using System.Data;
using System.Data.OleDb;

public class DatabaseInfo {    
 public static void Main () { 
   String connect = "Provider=Microsoft.JET.OLEDB.4.0;data source=.Employee.mdb";
   OleDbConnection con = new OleDbConnection(connect);
   con.Open();  
   Console.WriteLine("Made the connection to the database");

   Console.WriteLine("Information for each table contains:");
   DataTable tables = con.GetOleDbSchemaTable(OleDbSchemaGuid.Tables,new object[]{null,null,null,"TABLE"});

   Console.WriteLine("The tables are:");
   foreach(DataRow row in tables.Rows) 
     Console.Write("  {0}", row[2]);


   con.Close();
 }
}
 
           
          


Refernece column name in SqlDataReader

   


using System;
using System.Data.SqlClient;

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

      SqlCommand mySqlCommand = mySqlConnection.CreateCommand();

      mySqlCommand.CommandText =  "SELECT id, firstname, lastname from employee";

      mySqlConnection.Open();
      SqlDataReader mySqlDataReader = mySqlCommand.ExecuteReader();

      mySqlDataReader.Read();

      Console.WriteLine("mySqlDataReader[" ID"] = "+ mySqlDataReader["ID"]);
      Console.WriteLine("mySqlDataReader[" First Name"] = "+ mySqlDataReader["FirstName"]);
      Console.WriteLine("mySqlDataReader[" Last Name"] = "+ mySqlDataReader["LastName"]);

      mySqlDataReader.Close();

      mySqlConnection.Close();
    }
    catch (SqlException e)
    {
      Console.WriteLine("A SqlException was thrown");
      Console.WriteLine("Number = "+ e.Number);
      Console.WriteLine("Message = "+ e.Message);
      Console.WriteLine("StackTrace:
" + e.StackTrace);
    }
  }
}
           
          


Read column values as C# types using the 'Get' methods

   

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

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

    SqlCommand mySqlCommand = mySqlConnection.CreateCommand();

    mySqlCommand.CommandText = "SELECT TOP 5 ProductID, ProductName, UnitPrice, " +
      "UnitsInStock, Discontinued " +
      "FROM Products " +
      "ORDER BY ProductID";

    mySqlConnection.Open();

    SqlDataReader productsSqlDataReader = mySqlCommand.ExecuteReader();

    int productIDColPos = productsSqlDataReader.GetOrdinal("ProductID");
    int productNameColPos = productsSqlDataReader.GetOrdinal("ProductName");
    int unitPriceColPos = productsSqlDataReader.GetOrdinal("UnitPrice");
    int unitsInStockColPos = productsSqlDataReader.GetOrdinal("UnitsInStock");
    int discontinuedColPos = productsSqlDataReader.GetOrdinal("Discontinued");

    Console.WriteLine("ProductID .NET type = " + productsSqlDataReader.GetFieldType(productIDColPos));
    Console.WriteLine("ProductName .NET type = " + productsSqlDataReader.GetFieldType(productNameColPos));
    Console.WriteLine("UnitPrice .NET type = " + productsSqlDataReader.GetFieldType(unitPriceColPos));
    Console.WriteLine("UnitsInStock .NET type = " + productsSqlDataReader.GetFieldType(unitsInStockColPos));
    Console.WriteLine("Discontinued .NET type = " + productsSqlDataReader.GetFieldType(discontinuedColPos));

    Console.WriteLine("ProductID database type = " + productsSqlDataReader.GetDataTypeName(productIDColPos));
    Console.WriteLine("ProductName database type = " + productsSqlDataReader.GetDataTypeName(productNameColPos));
    Console.WriteLine("UnitPrice database type = " + productsSqlDataReader.GetDataTypeName(unitPriceColPos));
    Console.WriteLine("UnitsInStock database type = " + productsSqlDataReader.GetDataTypeName(unitsInStockColPos));
    Console.WriteLine("Discontinued database type = " + productsSqlDataReader.GetDataTypeName(discontinuedColPos));

    while (productsSqlDataReader.Read())
    {
      int productID = productsSqlDataReader.GetInt32(productIDColPos);
      Console.WriteLine("productID = " + productID);

      string productName = productsSqlDataReader.GetString(productNameColPos);
      Console.WriteLine("productName = " + productName);

      decimal unitPrice = productsSqlDataReader.GetDecimal(unitPriceColPos);
      Console.WriteLine("unitPrice = " + unitPrice);

      short unitsInStock = productsSqlDataReader.GetInt16(unitsInStockColPos);
      Console.WriteLine("unitsInStock = " + unitsInStock);

      bool discontinued = productsSqlDataReader.GetBoolean(discontinuedColPos);
      Console.WriteLine("discontinued = " + discontinued);
    }

    productsSqlDataReader.Close();
    mySqlConnection.Close();
  }
}



           
          


Geting Table column data type


   


using System;
using System.Data;
using System.Data.OleDb;

public class DatabaseInfo {    
 public static void Main () { 
   String connect = "Provider=Microsoft.JET.OLEDB.4.0;data source=.Employee.mdb";
   OleDbConnection con = new OleDbConnection(connect);
   con.Open();  
   Console.WriteLine("Made the connection to the database");

   Console.WriteLine("Information for each table contains:");
   DataTable tables = con.GetOleDbSchemaTable(OleDbSchemaGuid.Tables,new object[]{null,null,null,"TABLE"});
   foreach(DataColumn col in tables.Columns) 
     Console.WriteLine("{0}	{1}", col.ColumnName, col.DataType);

   con.Close();
 }
}
 
           
          


Call a store procedure

   

//Call a store procedure

/*
 * C# Programmers Pocket Consultant
 * Author: Gregory S. MacBeth
 * Email: gmacbeth@comporium.net
 * Create Date: June 27, 2003
 * Last Modified Date:
 * Version: 1
 */
using System;
using System.Data;
using System.Data.SqlClient;

namespace Client.Chapter_13___ADO.NET
{
    public class Callastoreprocedure
    {
        static void Main(string[] args)
        {
            SqlConnection cn = new SqlConnection(
            "Data Source=(local); Initial  Catalog = MyDatabase; User ID=sa;Password=");
            SqlCommand cmd = new SqlCommand("MyStoredProcedure", cn);
            cmd.CommandType = CommandType.StoredProcedure;
            SqlParameter param = new SqlParameter("@ReturnValue", SqlDbType.Int);
            cmd.Parameters.Add(param);
            cmd.Parameters.Add("MyFirstParameter", SqlDbType.Int);
            cmd.Parameters.Add("MySecondParameter", SqlDbType.Int).Direction =
            ParameterDirection.Output;
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            
        }
    }
}



          
          


illustrates how to call a SQL Server stored procedure

   

/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy

Publisher: Sybex;
ISBN: 0782129110
*/

/*
  Example23_7.cs illustrates how to call a SQL Server
  stored procedure
*/

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

public class Example23_7
{

  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 string containing the name of the
    // stored procedure
    string procedureString =
      "Ten Most Expensive Products";

    // create a SqlCommand object to hold the SQL statement
    SqlCommand mySqlCommand = mySqlConnection.CreateCommand();

    // set the CommandText property of the SqlCommand object to
    // procedureString
    mySqlCommand.CommandText = procedureString;

    // set the CommandType property of the SqlCommand object
    // to CommandType.StoredProcedure
    mySqlCommand.CommandType = CommandType.StoredProcedure;

    // open the database connection using the
    // Open() method of the SqlConnection object
    mySqlConnection.Open();

    // run the stored procedure
    mySqlCommand.ExecuteNonQuery();

    // 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 stored procedure call
    DataSet myDataSet = new DataSet();

    // use the Fill() method of the SqlDataAdapter object to
    // retrieve the rows from the stored procedure call,
    // storing the rows in a DataTable named Products
    mySqlDataAdapter.Fill(myDataSet, "Products");

    // display the rows in the Products DataTable
    Console.WriteLine("The ten most expensive products are:");
    DataTable products = myDataSet.Tables["Products"];
    foreach (DataRow product in products.Rows)
    {
      Console.WriteLine("Product name = " +
        product["TenMostExpensiveProducts"]);
      Console.WriteLine("Unit price = " +
        product["UnitPrice"]);

    }

    // close the database connection using the Close() method
    // of the SqlConnection object
    mySqlConnection.Close();

  }

}