SalesQuotationLine_ds and SalesQuotationTable_ds

Hi,

 I'm tryign to understand some code in \Forms\SalesQuotationTable\Methods\workflowSetAllowEdit.  Its doing something with enabling or disabling certain parts of the form but I can't see where the SalesQuotationLine_ds and SalesQuotationTable_ds objects are coming from or what they do. Can anyone give me a quick bit of background on these objects and how they are used?

Thanks

David