Commands and Parameters
After establishing a connection to a data source, you can execute commands and return results from the data source using a DbCommand object. You can create a command using one of the command constructors for the .NET Framework data provider you are working with. Constructors can take optional arguments, such as an SQL statement to execute at the data source, a DbConnection object, or a DbTransaction object. You can also configure those objects as properties of the command. You can also create a command for a particular connection using the CreateCommand method of a DbConnection object. The SQL statement being executed by the command can be configured using the CommandText property.
Each .NET Framework data provider included with the .NET Framework has a Command object. The .NET Framework Data Provider for OLE DB includes an OleDbCommand object, the .NET Framework Data Provider for SQL Server includes a SqlCommand object, the .NET Framework Data Provider for ODBC includes an OdbcCommand object, and the .NET Framework Data Provider for Oracle includes an OracleCommand object.