Fixed a bug where a new quantity was inserted when it hasnt changed

models/book.go

@@ -57,9 +57,19 @@ func GetQuantityByBook(book Book) (quantity int64, err error) {
 
 // SetBookQuantity sets a new quantity for a book
 func (book Book) setBookQuantity(quantity int64) (err error) {
-	q := Quantity{BookID: book.ID, Quantity: quantity}
-	_, err = x.Insert(q)
-	return err
+	// Check if the quantity already exists and only insert it if not
+	qty, err := GetQuantityByBook(book)
+	if err != nil {
+		return err
+	}
+
+	if qty != quantity {
+		q := Quantity{BookID: book.ID, Quantity: quantity}
+		_, err = x.Insert(q)
+		return err
+	}
+
+	return nil
 }
 
 // GetBookByID gets a Book by its ID