diff --git a/models/author.go b/models/author.go
index e6086e7..8d0602e 100644
--- a/models/author.go
+++ b/models/author.go
@@ -37,12 +37,12 @@ func GetAuthorByID(id int64) (author Author, exists bool, err error) {
 }
 
 // GetAuthorsByBook get all authors of a book
-func GetAuthorsByBook(bookID int64) (authors []Author, err error) {
+func GetAuthorsByBook(book Book) (authors []Author, err error) {
 	err = x.
 		Select("authors.*").
 		Table("authors_books").
 		Join("INNER", "authors", "authors_books.author_id = authors.id").
-		Where("book_id = ?", bookID).
+		Where("book_id = ?", book.ID).
 		Find(&authors)
 
 	if err != nil {
diff --git a/models/book.go b/models/book.go
index e428170..62a48dc 100644
--- a/models/book.go
+++ b/models/book.go
@@ -40,8 +40,8 @@ func (Quantity) TableName() string {
 }
 
 // GetQuantityByBook returns the current quantity for a book
-func GetQuantityByBook(bookID int64) (quantity int64, err error) {
-	bq := Quantity{BookID: bookID}
+func GetQuantityByBook(book Book) (quantity int64, err error) {
+	bq := Quantity{BookID: book.ID}
 	has, err := x.Desc("id").Get(&bq)
 	if err != nil {
 		return 0, err
@@ -68,7 +68,7 @@ func GetBookByID(ID int64) (book Book, exists bool, err error) {
 
 	if has {
 		// Get the books quantity. We can't join it because xorm ignores the Quantity option in struct
-		book.Quantity, err = GetQuantityByBook(ID)
+		book.Quantity, err = GetQuantityByBook(book)
 		if err != nil {
 			fmt.Println("Error getting quantity:", err)
 		}
@@ -80,7 +80,7 @@ func GetBookByID(ID int64) (book Book, exists bool, err error) {
 		}
 
 		// Get all authors
-		book.Authors, err = GetAuthorsByBook(book.ID)
+		book.Authors, err = GetAuthorsByBook(book)
 		if err != nil {
 			fmt.Println("Error getting authors:", err)
 		}
diff --git a/models/books_list.go b/models/books_list.go
index eaa8b18..77c2714 100644
--- a/models/books_list.go
+++ b/models/books_list.go
@@ -29,7 +29,7 @@ func ListBooks(searchterm string) (books []*Book, err error) {
 	for i, book := range books {
 
 		// Get quantities
-		books[i].Quantity, err = GetQuantityByBook(book.ID)
+		books[i].Quantity, err = GetQuantityByBook(*book)
 		if err != nil {
 			fmt.Println("Error getting quantity:", err)
 		}
@@ -41,7 +41,7 @@ func ListBooks(searchterm string) (books []*Book, err error) {
 		}
 
 		// Get all authors
-		books[i].Authors, err = GetAuthorsByBook(book.ID)
+		books[i].Authors, err = GetAuthorsByBook(*book)
 		if err != nil {
 			fmt.Println("Error getting authors:", err)
 		}
diff --git a/models/user.go b/models/user.go
index 8334b50..3142a52 100644
--- a/models/user.go
+++ b/models/user.go
@@ -29,15 +29,16 @@ func (User) TableName() string {
 
 // GetUserByID gets informations about a user by its ID
 func GetUserByID(id int64) (user User, exists bool, err error) {
-	exists, err = x.Id(id).Get(&user)
-	return user, exists, err
+	/*exists, err = x.Id(id).Get(&user)
+	return user, exists, err*/
+	return GetUser(User{ID: id})
 }
 
-// GetUserByUsername returns a User struct based on its name
-func GetUserByUsername(username string) (user User, exists bool, err error) {
-	user.Username = username
-	exists, err = x.Get(&user)
-	return user, exists, err
+// GetUser gets a user object
+func GetUser(user User) (userOut User, exists bool, err error) {
+	userOut = user
+	exists, err = x.Get(&userOut)
+	return userOut, exists, err
 }
 
 // CreateUser creates a new user and inserts it into the database
@@ -50,8 +51,8 @@ func CreateUser(user User) (newUser User, err error) {
 		return User{}, fmt.Errorf("you need to specify at least a username and a password")
 	}
 
-	// Check if the user already exists
-	_, exists, err := GetUserByUsername(newUser.Username)
+	// Check if the user already existst
+	_, exists, err := GetUser(User{Name: newUser.Name})
 	if err != nil {
 		return User{}, err
 	}