Executes an SQL statement against the Connection and returns the number of rows affected.
Assembly: System.Data (in System.Data.dll)
The connection does not exist.
The connection is not open.
You can use to perform catalog operations (for example, querying the structure of a database or creating database objects such as tables); or to change the data in a database, without using a DataSet, by executing UPDATE, INSERT, or DELETE statements.
You can also use to execute multiple SQL statements if the underlying ODBC driver supports this functionality. In this case, the return value is the number of rows affected by all statements in the command.
Although returns no rows, any output parameters or return values mapped to parameters are populated with data.
For UPDATE, INSERT, and DELETE statements, the return value is the number of rows affected by the command. For all other types of statements, the return value is -1. If a rollback occurs, the return value is also -1.
When a trigger exists on a table and data is being added or changed in the table, the return value includes the number of rows affected by both the insert or update operation and the number of rows affected by the trigger or triggers.