Tài liệu Creating a Sqldatareader Objec ppt

Creating a SqlDataReader Object You can create a DataReader object only by calling the ExecuteReader() method of a Command object. Command objects were covered in the previous chapter . For example, the following code creates the required objects and executes a SELECT statement that retrieves the top five rows from the Products table of the SQL Server Northwind database, storing the returned rows in a SqlDataReader object: SqlConnection mySqlConnection = new SqlConnection( "server=localhost;database=Northwind;uid=sa;pwd=sa" ); SqlCommand mySqlCommand = mySqlConnection.CreateCommand(); mySqlCommand.CommandText = "SELECT TOP 5 ProductID, ProductName, UnitPrice, " + "UnitsInStock, Discontinued " + "FROM Products " + "ORDER BY ProductID"; mySqlConnection.Open(); SqlDataReader productsSqlDataReader = mySqlCommand.ExecuteReader(); Notice that the SqlDataReader object returned by the ExecuteReader() method is stored in the productsSqlDataReader object. You'll see how to use productsSqlDataReader in the following section. . Creating a SqlDataReader Object You can create a DataReader object only by calling the ExecuteReader() method of a Command object. Command objects. mySqlConnection.Open(); SqlDataReader productsSqlDataReader = mySqlCommand.ExecuteReader(); Notice that the SqlDataReader object returned by the ExecuteReader() method