CommandType can be one of the following values: Text, StoredProcedure, TableDirect.
When the value is System.Data.CommandType.Text, property CommandText should contain text of a query that must be run on the server.
When the value is System.Data.CommandType.StoredProcedure, CommandText property must be a name of a procedure to execute.
When the value is set to System.Data.CommandType.TableDirect, CommandText must be name of a table you want to get all data from. All rows and columns are retrieved.