UniCommand Class

In This Topic

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

Syntax

Visual Basic
C#

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

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

Remarks

The UniCommand class provides the following methods for executing commands against the a database:

Item	Description
ExecuteReader	Executes commands that return rows.
ExecuteNonQuery	Executes SQL commands such as INSERT, DELETE, UPDATE or PL/SQL block.
ExecuteScalar	Retrieves a single value (for example, an aggregate value) from a database.

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

Example

The following example uses the ExecuteReader method of UniCommand, along with UniDataReader and UniConnection, to select rows from a table.

csharp

public void ReadMyData(string myConnString)
{
  string mySelectQuery = "SELECT * FROM Test.Dept";
  UniConnection myConnection = new UniConnection(myConnString);
  UniCommand myCommand = new UniCommand(mySelectQuery,myConnection);
  myConnection.Open();
  UniDataReader myReader = myCommand.ExecuteReader();
  try
  {
    while (myReader.Read())
    {
      Console.WriteLine(myReader.GetInt32(0) + ", " + 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 * FROM Test.Dept"
  Dim myConnection As New UniConnection(myConnString)
  Dim myCommand As New UniCommand(mySelectQuery, myConnection)
  myConnection.Open()
  Dim myReader As UniDataReader = 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.Universal.UniCommand

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

UniCommand Members
Devart.Data.Universal Namespace
UniDataReader Class
UniConnection Class

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