Naming conventions for Form datasources
Datasources name must match the name of the table used. In form extensions - with the _PRJ suffix.
Tables\PurchTable_PRJ (new table)
Forms\PurchTable.Extension_PRJ (form extension)
Forms\PurchTable.Extension_PRJ\Datasources\VendTable_PRJ (new datasource on form extension)
Forms\VendInvoiceJour.Extension_PRJ\Datasources\PurchTable_PRJ (table PurchTable)
Forms\VendInvoiceJour.Extension_PRJ\Datasources\PurchTable_PRJ_PRJ (table PurchTable_PRJ)
Datasource name for temporary table should be same as table name.
Tables\TmpEcoResCategoryImport_PRJ
Forms\EcoResCategoryImportForm_PRJ\Datasources\TmpEcoResCategoryImport_PRJ