MySqlDataReader Class

In This Topic

Syntax
Remarks
Example
Inheritance Hierarchy
See Also

Reads a forward-only stream of rows from MySQL.

Syntax

Visual Basic
C#

public class MySqlDataReader : Devart.Common.DbDataReaderBase, System.Collections.IEnumerable, System.Data.IDataReader, System.Data.IDataRecord, System.IDisposable

'Declaration
 
Public Class MySqlDataReader 
   Inherits Devart.Common.DbDataReaderBase
   Implements System.Collections.IEnumerable, System.Data.IDataReader, System.Data.IDataRecord, System.IDisposable

Remarks

To create a MySqlDataReader, you must call the ExecuteReader method of the MySqlCommand object, rather than directly using a constructor.

System.Data.Common.DbDataReader.IsClosed and Devart.Data.SqlShimDataReader.RecordsAffected are the only properties that you can call after the MySqlDataReader is closed. In some cases, you must call Devart.Data.SqlShimDataReader.Close before you can call Devart.Data.SqlShimDataReader.RecordsAffected.

While the MySqlDataReader is in use, the associated MySqlConnection is busy serving the MySqlDataReader, and no other operations can be performed on the MySqlConnection other than closing it. This is the case until the Close method of the MySqlDataReader is called. For example, you cannot retrieve output parameters until you call Close.

Example

The following example creates a MySqlConnection, a MySqlCommand, and a MySqlDataReader. The example reads through the data, writing it out to the console. Finally, the example closes the MySqlDataReader, then the MySqlConnection.

csharp

public void ReadMyData(string myConnString)  {
        MySqlConnection myConnection = new MySqlConnection(myConnString);
        MySqlCommand myCommand = (MySqlCommand)myConnection.CreateCommand();
        myCommand.CommandText = "SELECT DeptNo, DName, Loc FROM Test.Dept";
        myConnection.Open();
        MySqlDataReader myReader = myCommand.ExecuteReader();
        try {
                // Always call Read before accessing data.
                while (myReader.Read()) {
                Console.WriteLine(myReader.GetInt32(0).ToString() + " " + 
                myReader.GetString(1) + " " + myReader.GetString(2));
        }
        }
        finally {
                // always call Close when done reading.
                myReader.Close();

                // Close the connection when done with it.
                myConnection.Close();
        }
}

Visual Basic

Public Sub ReadMyData(ByVal myConnString As String)
        Dim myConnection As New MySqlConnection(myConnString)
        Dim myCommand As MySqlCommand = myConnection.CreateCommand()
                myCommand.CommandText = "SELECT DeptNo, DName, Loc FROM Test.Dept"
        myConnection.Open()
        Dim myReader As MySqlDataReader = myCommand.ExecuteReader()
        Try
                ' Always call Read before accessing data.
                While myReader.Read()
                        Console.WriteLine(String.Concat(myReader.GetInt32(0).ToString(), " ", _
                        myReader.GetString(1), " ", myReader.GetString(2)))
                End While
        Finally
                ' always call Close when done reading.
                myReader.Close()

                        ' Close the connection when done with it.
                        myConnection.Close()
        End Try
End Sub

Inheritance Hierarchy

System.Object
   System.MarshalByRefObject
      System.Data.Common.DbDataReader
         Devart.Common.DbDataReaderBase
            Devart.Data.MySql.MySqlDataReader

Reference

MySqlDataReader Members
Devart.Data.MySql Namespace
MySqlConnection Class
MySqlCommand Class

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