UniCommand Class

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

For a list of all members of this type, see UniCommand members.

Inheritance Hierarchy

System.Object
   System.MarshalByRefObject
      System.ComponentModel.Component
         System.Data.Common.DbCommand
            Devart.Common.DbCommandBase
               Devart.Data.Universal.UniCommand

Syntax

[Visual Basic]
Public Class UniCommand 
   Inherits DbCommandBase

[C#]
public class UniCommand : DbCommandBase

Remarks

The UniCommand class provides the following methods for executing commands against the a database:
Item Description
ExecuteReader Executes commands that return rows.
Devart.Common.DbCommandBase.ExecuteNonQuery Executes SQL commands such as INSERT, DELETE, UPDATE or PL/SQL block.
Devart.Common.DbCommandBase.ExecuteScalar Retrieves a single value (for example, an aggregate value) from a database.

Item	Description
ExecuteReader	Executes commands that return rows.
Devart.Common.DbCommandBase.ExecuteNonQuery	Executes SQL commands such as INSERT, DELETE, UPDATE or PL/SQL block.
Devart.Common.DbCommandBase.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.

[C#]

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

See Also

Language