Validate The salesLine unit price should not less than the item cost price

SalesTable(form)->DS->SalesLine->salePrice(Field)->Validate()

public boolean validate()
{
boolean ret;

ret = super();
ret = element.validate_price();

return ret;
}
--
SalesTable(form)->Methods->

public boolean validate_price()
{
boolean ret = true;
InventTableModule inventTableModule;

;
//in this line we are using our own find method, or we can use select query.
//inventTableModule = InventTableModule::find_price(SalesLine.ItemId);
select firstonly inventTableModule where inventTableModule.ItemId == SalesLine.ItemId;

if(inventTableModule.Price > SalesLine.SalesPrice)
{
ret = false;
info("the cost price is grater then the sales price ");
}

return ret;
}