Improved performance when getting a list of all books

models/books_list.go

@@ -22,19 +22,38 @@ func ListBooks(searchterm string) (books []*Book, err error) {
 		}
 	}
 
-	// Get all authors, publishers and quantities
+	// Get all publishers and quantities to afterwards loop though them (less sql queries -> more performance)
+	// Publishers
+	pubs, err := ListPublishers("")
+	if err != nil {
+		return []*Book{}, err
+	}
+
+	// Quantites
+	allq := []Quantity{}
+	err = x.Table("quantities").
+	Select("quantities.id, quantity_relations.book_id AS item_id, quantities.quantity, quantities.created").
+	Join("INNER", "quantity_relations", "quantities.item_id = quantity_relations.id").
+	Where("quantity_relations.book_id != 0").
+	Desc("quantities.created").
+	Find(&allq)
+
+	// Link them
 	for i, book := range books {
 
-		// Get quantities
-		books[i].Quantity, err = book.getQuantity()
-		if err != nil {
-			return []*Book{}, err
+		// Set quantities
+		for _, qy := range allq {
+			if qy.ItemID == book.ID {
+				books[i].Quantity = qy.Quantity
+				break // Take the first quantity you find and exit
+			}
 		}
 
 		// Get publisher
-		books[i].Publisher, _, err = GetPublisherByID(book.PublisherID)
-		if err != nil {
-			return []*Book{}, err
+		for _, pub := range pubs {
+			if pub.ID == book.PublisherID {
+				books[i].Publisher = pub
+			}
 		}
 
 		// Get all authors