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26.2.4.4.3. 从MySQL Connector/NET调用存储程序

要想使用MySQL Connector/NET来调用存储程序,应创建1个MySqlCommand对象,并将存储程序名作为.CommandText属性传递。将.CommandType属性设置为CommandType.StoredProcedure。

命名了存储程序后,为存储程序中的每个参数创建1个MySqlCommand参数。用参数名和包含值的对象定义IN参数,用参数名和预计将返回的数据类型定义OUT参数。对于所有参数,均需定义参数方向。

定义完参数后,使用MySqlCommand.ExecuteNonQuery()方法调用存储程序。

[VB]

Dim conn As New MySqlConnection
Dim cmd As New MySqlCommand

conn.ConnectionString = "server=127.0.0.1;" _
    & "uid=root;" _
    & "pwd=12345;" _
    & "database=test"

Try
    conn.Open()
    cmd.Connection = conn

    cmd.CommandText = "add_emp"
    cmd.CommandType = CommandType.StoredProcedure

    cmd.Parameters.Add("?lname", 'Jones')
    cmd.Parameters("?lname").Direction = ParameterDirection.Input

    cmd.Parameters.Add("?fname", 'Tom')
    cmd.Parameters("?fname").Direction = ParameterDirection.Input

    cmd.Parameters.Add("?bday", #12/13/1977 2:17:36 PM#)
    cmd.Parameters("?bday").Direction = ParameterDirection.Input

    cmd.Parameters.Add("?empno", MySqlDbType.Int32)
    cmd.Parameters("?empno").Direction = ParameterDirection.Output

    cmd.ExecuteNonQuery()

    MessageBox.Show(cmd.Parameters("?empno").Value)
Catch ex As MySqlException
    MessageBox.Show("Error " & ex.Number & " has occurred: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try

[C#]

MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;

conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();

conn.ConnectionString = "server=127.0.0.1;uid=root;" +
    "pwd=12345;database=test;";

try
{
    conn.Open();
    cmd.Connection = conn;

    cmd.CommandText = "add_emp";
    cmd.CommandType = CommandType.StoredProcedure;

    cmd.Parameters.Add("?lname", "Jones");
    cmd.Parameters("?lname").Direction = ParameterDirection.Input;

    cmd.Parameters.Add("?fname", "Tom");
    cmd.Parameters("?fname").Direction = ParameterDirection.Input;

    cmd.Parameters.Add("?bday", DateTime.Parse("12/13/1977 2:17:36 PM"));
    cmd.Parameters("?bday").Direction = ParameterDirection.Input;

    cmd.Parameters.Add("?empno", MySqlDbType.Int32);
    cmd.Parameters("?empno").Direction = ParameterDirection.Output;

    cmd.ExecuteNonQuery();

    MessageBox.Show(cmd.Parameters("?empno").Value);
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
    MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message,
      "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
一旦调用了存储程序,可使用MySqlConnector.Parameters集的.Value属性检索输出参数的值。