Updating Data
Like
TextReader
and XmlReader
,
DataReader
provides a read-only, forward-only view
of the underlying data stream. This means that updating a database
requires a new IDbCommand
and the
ExecuteNonQuery( )
method, which I mentioned
earlier.
Example 11-2 shows a program to insert a new coupon into the database.
using System; using System.Data.SqlClient; public enum DiscountType { Percentage, Fixed } public class AddCoupon { public static void Main(string [ ] args) { SqlConnection connection = new SqlConnection( "Initial Catalog=AngusHardware; User ID=sa"); SqlCommand command = new SqlCommand( "insert into coupons ( coupon_code, discount_amount, discount_type, expiration_date ) " + "values ( '077GH', 15, " + (int)DiscountType.Percentage + ", '11/30/2002' )", connection); connection.Open( ); command.ExecuteNonQuery( ); connection.Close( ); } }
The
SqlCommand.ExecuteNonQuery( )
method simply
executes the SQL command without expecting any values to be returned.
If you’re familiar with SQL, this
insert
statement should need no explanation.
Get .NET & XML now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.