IDbCommand interface represents a command that
can be executed against a data source. Some examples include queries
that retrieve rows (a SQL SELECT statement), statements that retrieve
a single piece of information (such as SQL aggregate functions), or
statements designed to modify rows (such as a SQL UPDATE, DELETE, or
INSERT statement). ADO.NET providers that access relational data
implement this interface.
Before, using the command, you must set the
Connection property to a valid
IDbConnection and open the connection. You can
then execute the command in one of three ways. Use
ExecuteNonQuery( ) to execute a statement such as
INSERT, DELETE, or UPDATE, which returns the number of rows affected.
ExecuteScalar( ) to execute a statement that
returns a single value, such as an aggregate SQL function (SUM, MAX,
MIN, AVG, and so on). Finally, use
ExecuteReader( ) to perform a query and return a
IDataReader that provides access to the result
CommandTimeout property identifies the
number of seconds ADO.NET will wait while trying to execute the
command before throwing a provider-specific exception. The default is
30, and 0 represents an infinite wait. Finally, if you are using a
stored procedure, you can use the
Prepare( ) method to compile the stored procedure in the data source, which may improve performance with some providers if you are executing the same stored procedure multiple times with different parameters. (It’s recommended that you profile ...