SqlCommand Class

In This Topic

Represents a SQL statement or stored procedure to execute against SQL Server.

Syntax

Visual Basic
C#

'Declaration
 
Public Class SqlCommand 
   Inherits Devart.Common.DbCommandBase
   Implements System.ComponentModel.IComponent, System.Data.IDbCommand, System.ICloneable, System.IDisposable

public class SqlCommand : Devart.Common.DbCommandBase, System.ComponentModel.IComponent, System.Data.IDbCommand, System.ICloneable, System.IDisposable

Remarks

The SqlCommand class provides the following methods for executing commands against the SQL Server database:

Item	Description
ExecuteReader	Executes commands that return rows.
ExecutePageReader	Returns a specific subset of rows when paging through the results of a query.
ExecuteNonQuery	Executes SQL commands such as INSERT, DELETE, UPDATE.
ExecuteScalar	Retrieves a single value (for example, an aggregate value) from a data source.

If execution of the command results in a fatal SqlException, the SqlConnection may close. However, the user can reopen the connection and continue.

This class supports cross-form data binding with the InterForm Technology.

Example

The following example uses the ExecuteReader method of SqlCommand, along with SqlDataReader and SqlConnection, to select rows from a table.

csharp

public void ReadMyData(string myConnString)
{
  string mySelectQuery = "SELECT DeptNo, DName FROM Test.Dept";
  SqlConnection myConnection = new SqlConnection(myConnString);
  SqlCommand myCommand = new SqlCommand(mySelectQuery,myConnection);
  myConnection.Open();
  SqlDataReader myReader = myCommand.ExecuteReader();
  try
  {
    while (myReader.Read())
    {
      Console.WriteLine(myReader.GetInt32(0).ToString() + ", " + myReader.GetString(1));
    }
  }
  finally
  {
  // always call Close when done reading.
  myReader.Close();
  // always call Close when done reading.
  myConnection.Close();
  }
}

Visual Basic

Public Sub ReadMyData(myConnString As String)
  Dim mySelectQuery As String = "SELECT DeptNo, DName FROM Test.Dept"
  Dim myConnection As New SqlConnection(myConnString)
  Dim myCommand As New SqlCommand(mySelectQuery, myConnection)
  myConnection.Open()
  Dim myReader As SqlDataReader = myCommand.ExecuteReader()
  Try
    While myReader.Read()
      Console.WriteLine(myReader.GetInt32(0).ToString() + ", " _
        + myReader.GetString(1))
    End While
  Finally
      ' always call Close when done reading.
      myReader.Close()
      ' always call Close when done with connection.
      myConnection.Close()
  End Try
End Sub

Inheritance Hierarchy

System.Object
   System.MarshalByRefObject
      System.ComponentModel.Component
         System.Data.Common.DbCommand
            Devart.Common.DbCommandBase
               Devart.Data.SqlServer.SqlCommand

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

SqlCommand Members
Devart.Data.SqlServer Namespace
SqlDataReader Class
SqlConnection Class

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