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.
Devart.Common.DbCommandBase.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

Reference

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

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