Misc changes:

- Rename BookcaseLocation -> BookcaseShelf
- Remove `name` from BookcaseShelfs, and use columns and rows to index
  them instead
- Add `amount` to BookcaseItem, and make isbn unique
- Remove ability to use scanner tool without database
- Add a lot of real bookshelfs to seeding data

worblehat/flaskapp.py

@@ -32,7 +32,7 @@ def configure_admin(app):
     admin.add_view(ModelView(Author, db.session))
     admin.add_view(ModelView(Bookcase, db.session))
     admin.add_view(ModelView(BookcaseItem, db.session))
-    admin.add_view(ModelView(BookcaseLocation, db.session))
+    admin.add_view(ModelView(BookcaseShelf, db.session))
     admin.add_view(ModelView(Category, db.session))
     admin.add_view(ModelView(Language, db.session))
     admin.add_view(ModelView(MediaType, db.session))

worblehat/models/Bookcase.py

@@ -14,12 +14,12 @@ from .mixins import (
     UniqueNameMixin,
 )
 if TYPE_CHECKING:
-    from .BookcaseLocation import BookcaseLocation
+    from .BookcaseShelf import BookcaseShelf
 
 class Bookcase(Base, UidMixin, UniqueNameMixin):
     description: Mapped[str | None] = mapped_column(Text)
 
-    locations: Mapped[list[BookcaseLocation]] = relationship(back_populates='bookcase')
+    shelfs: Mapped[list[BookcaseShelf]] = relationship(back_populates='bookcase')
 
     def __init__(
         self,

worblehat/models/BookcaseItem.py

@@ -3,6 +3,7 @@ from typing import TYPE_CHECKING
 
 from sqlalchemy import (
   Integer,
+  SmallInteger,
   String,
   ForeignKey,
 )
@@ -23,23 +24,22 @@ from .xref_tables import (
 )
 if TYPE_CHECKING:
     from .Author import Author
-    from .BookcaseLocation import BookcaseLocation
+    from .BookcaseShelf import BookcaseShelf
     from .Category import Category
     from .Language import Language
     from .MediaType import MediaType
 
 class BookcaseItem(Base, UidMixin, UniqueNameMixin):
-    # NOTE: This is kept non-unique in case we have
+    isbn: Mapped[int] = mapped_column(String, unique=True, index=True)
-    #       multiple copies of the same book.
-    isbn: Mapped[int | None] = mapped_column(String, index=True)
     owner: Mapped[str] = mapped_column(String, default='PVV')
+    amount: Mapped[int] = mapped_column(SmallInteger, default=1)
 
     fk_media_type_uid: Mapped[int] = mapped_column(Integer, ForeignKey('MediaType.uid'))
-    fk_bookcase_location_uid: Mapped[int | None] = mapped_column(Integer, ForeignKey('BookcaseLocation.uid'))
+    fk_bookcase_shelf_uid: Mapped[int | None] = mapped_column(Integer, ForeignKey('BookcaseShelf.uid'))
     fk_language_uid: Mapped[int] = mapped_column(Integer, ForeignKey('Language.uid'))
 
     media_type: Mapped[MediaType] = relationship(back_populates='items')
-    location: Mapped[BookcaseLocation] = relationship(back_populates='items')
+    shelf: Mapped[BookcaseShelf] = relationship(back_populates='items')
     language: Mapped[Language] = relationship()
 
     categories: Mapped[set[Category]] = relationship(

worblehat/models/BookcaseShelf.py

@@ -4,7 +4,9 @@ from typing import TYPE_CHECKING
 from sqlalchemy import (
     Integer,
     ForeignKey,
+    SmallInteger,
     Text,
+    UniqueConstraint,
 )
 from sqlalchemy.orm import (
     Mapped,
@@ -13,28 +15,39 @@ from sqlalchemy.orm import (
 )
 
 from .Base import Base
-from .mixins import (
+from .mixins import UidMixin
-    UidMixin,
-    UniqueNameMixin,
-)
 if TYPE_CHECKING:
     from .Bookcase import Bookcase
     from .BookcaseItem import BookcaseItem
 
-class BookcaseLocation(Base, UidMixin, UniqueNameMixin):
+# NOTE: Booshelfs are 0 indexed for both rows and columns,
+#       where cell 0-0 is placed in the lower right corner.
+
+class BookcaseShelf(Base, UidMixin):
+    __table_args__ = (
+        UniqueConstraint(
+            'column',
+            'fk_bookcase_uid',
+            'row',
+        ),
+    )
     description: Mapped[str | None] = mapped_column(Text)
+    row: Mapped[int] = mapped_column(SmallInteger)
+    column: Mapped[int] = mapped_column(SmallInteger)
 
     fk_bookcase_uid: Mapped[int] = mapped_column(Integer, ForeignKey('Bookcase.uid'))
 
-    bookcase: Mapped[Bookcase] = relationship(back_populates='locations')
+    bookcase: Mapped[Bookcase] = relationship(back_populates='shelfs')
-    items: Mapped[set[BookcaseItem]] = relationship(back_populates='location')
+    items: Mapped[set[BookcaseItem]] = relationship(back_populates='shelf')
 
     def __init__(
         self,
-        name: str,
+        row: int,
+        column: int,
         bookcase: Bookcase,
         description: str | None = None,
     ):
-        self.name = name
+        self.row = row
+        self.column = column
         self.bookcase = bookcase
         self.description = description

worblehat/models/Language.py

@@ -12,7 +12,7 @@ from .Base import Base
 from .mixins import UidMixin, UniqueNameMixin
 
 class Language(Base, UidMixin, UniqueNameMixin):
-    iso639_1_code: Mapped[str] = mapped_column(String(2))
+    iso639_1_code: Mapped[str] = mapped_column(String(2), unique=True, index=True)
 
     def __init__(
         self,

worblehat/models/__init__.py

@@ -2,7 +2,7 @@ from .Author import Author
 from .Base import Base
 from .Bookcase import Bookcase
 from .BookcaseItem import BookcaseItem
-from .BookcaseLocation import BookcaseLocation
+from .BookcaseShelf import BookcaseShelf
 from .Category import Category
 from .Language import Language
 from .MediaType import MediaType

worblehat/seed_test_data.py

@@ -5,7 +5,7 @@ from flask_sqlalchemy import SQLAlchemy
 
 from .models import (
     Bookcase,
-    BookcaseLocation,
+    BookcaseShelf,
     Language,
     MediaType,
 )
@@ -19,15 +19,100 @@ def seed_data(db: SQLAlchemy):
     ]
 
     bookcases = [
-        Bookcase(name='A', description='The first bookcase'),
+        Bookcase(name='Unnamed A', description='White case across dibbler'),
-        Bookcase(name='B', description='The second bookcase'),
+        Bookcase(name='Unnamed B', description='Math case in the working room'),
+        Bookcase(name='Unnamed C', description='Large case in the working room'),
+        Bookcase(name='Unnamed D', description='White comics case in the hallway'),
+        Bookcase(name='Unnamed E', description='Wooden comics case in the hallway'),
     ]
 
-    locations = [
+    shelfs = [
-        BookcaseLocation(name='1-1', description='The first location', bookcase=bookcases[0]),
+        BookcaseShelf(row=0, column=0, bookcase=bookcases[0]),
-        BookcaseLocation(name='1-2', description='The second location', bookcase=bookcases[0]),
+        BookcaseShelf(row=1, column=0, bookcase=bookcases[0]),
-        BookcaseLocation(name='2-1', description='The third location', bookcase=bookcases[1]),
+        BookcaseShelf(row=2, column=0, bookcase=bookcases[0]),
-        BookcaseLocation(name='2-2', description='The fourth location', bookcase=bookcases[1]),
+        BookcaseShelf(row=3, column=0, bookcase=bookcases[0], description="Hacking"),
+        BookcaseShelf(row=4, column=0, bookcase=bookcases[0], description="Hacking"),
+
+        BookcaseShelf(row=0, column=1, bookcase=bookcases[0]),
+        BookcaseShelf(row=1, column=1, bookcase=bookcases[0]),
+        BookcaseShelf(row=2, column=1, bookcase=bookcases[0], description="DOS"),
+        BookcaseShelf(row=3, column=1, bookcase=bookcases[0], description="Food for thought"),
+        BookcaseShelf(row=4, column=1, bookcase=bookcases[0], description="CPP"),
+
+        BookcaseShelf(row=0, column=2, bookcase=bookcases[0]),
+        BookcaseShelf(row=1, column=2, bookcase=bookcases[0]),
+        BookcaseShelf(row=2, column=2, bookcase=bookcases[0], description="E = mc2"),
+        BookcaseShelf(row=3, column=2, bookcase=bookcases[0], description="OBJECTION!"),
+        BookcaseShelf(row=4, column=2, bookcase=bookcases[0], description="/home"),
+
+        BookcaseShelf(row=0, column=3, bookcase=bookcases[0]),
+        BookcaseShelf(row=1, column=3, bookcase=bookcases[0], description="Big indonisian island"),
+        BookcaseShelf(row=2, column=3, bookcase=bookcases[0]),
+        BookcaseShelf(row=3, column=3, bookcase=bookcases[0], description="Div science"),
+        BookcaseShelf(row=4, column=3, bookcase=bookcases[0], description="/home"),
+
+        BookcaseShelf(row=0, column=4, bookcase=bookcases[0]),
+        BookcaseShelf(row=1, column=4, bookcase=bookcases[0]),
+        BookcaseShelf(row=2, column=4, bookcase=bookcases[0], description="(not) computer vision"),
+        BookcaseShelf(row=3, column=4, bookcase=bookcases[0], description="Low voltage"),
+        BookcaseShelf(row=4, column=4, bookcase=bookcases[0], description="/home"),
+
+        BookcaseShelf(row=0, column=5, bookcase=bookcases[0]),
+        BookcaseShelf(row=1, column=5, bookcase=bookcases[0]),
+        BookcaseShelf(row=2, column=5, bookcase=bookcases[0], description="/home"),
+        BookcaseShelf(row=3, column=5, bookcase=bookcases[0], description="/home"),
+
+        BookcaseShelf(row=0, column=0, bookcase=bookcases[1]),
+        BookcaseShelf(row=1, column=0, bookcase=bookcases[1], description="Kjellerarealer og komodovaraner"),
+        BookcaseShelf(row=2, column=0, bookcase=bookcases[1]),
+        BookcaseShelf(row=3, column=0, bookcase=bookcases[1], description="Quick mafs"),
+        BookcaseShelf(row=4, column=0, bookcase=bookcases[1]),
+
+        BookcaseShelf(row=0, column=0, bookcase=bookcases[2]),
+        BookcaseShelf(row=1, column=0, bookcase=bookcases[2]),
+        BookcaseShelf(row=2, column=0, bookcase=bookcases[2], description="AI"),
+        BookcaseShelf(row=3, column=0, bookcase=bookcases[2], description="X86"),
+        BookcaseShelf(row=4, column=0, bookcase=bookcases[2], description="Humanoira"),
+        BookcaseShelf(row=5, column=0, bookcase=bookcases[2], description="Hvem monterte rørforsterker?"),
+
+        BookcaseShelf(row=0, column=1, bookcase=bookcases[2]),
+        BookcaseShelf(row=1, column=1, bookcase=bookcases[2], description="Div data"),
+        BookcaseShelf(row=2, column=1, bookcase=bookcases[2], description="Chemistry"),
+        BookcaseShelf(row=3, column=1, bookcase=bookcases[2], description="Soviet Phys. Techn. Phys"),
+        BookcaseShelf(row=4, column=1, bookcase=bookcases[2], description="Digitalteknikk"),
+        BookcaseShelf(row=5, column=1, bookcase=bookcases[2], description="Material"),
+
+        BookcaseShelf(row=0, column=2, bookcase=bookcases[2]),
+        BookcaseShelf(row=1, column=2, bookcase=bookcases[2], description="Assembler / APL"),
+        BookcaseShelf(row=2, column=2, bookcase=bookcases[2], description="Internet"),
+        BookcaseShelf(row=3, column=2, bookcase=bookcases[2], description="Algorithms"),
+        BookcaseShelf(row=4, column=2, bookcase=bookcases[2], description="Soviet Physics Jetp"),
+        BookcaseShelf(row=5, column=2, bookcase=bookcases[2], description="Død og pine"),
+
+        BookcaseShelf(row=0, column=3, bookcase=bookcases[2]),
+        BookcaseShelf(row=1, column=3, bookcase=bookcases[2], description="Web"),
+        BookcaseShelf(row=2, column=3, bookcase=bookcases[2], description="Div languages"),
+        BookcaseShelf(row=3, column=3, bookcase=bookcases[2], description="Python"),
+        BookcaseShelf(row=4, column=3, bookcase=bookcases[2], description="D&D Minis"),
+        BookcaseShelf(row=5, column=3, bookcase=bookcases[2], description="Perl"),
+
+        BookcaseShelf(row=0, column=4, bookcase=bookcases[2]),
+        BookcaseShelf(row=1, column=4, bookcase=bookcases[2], description="Knuth on programming"),
+        BookcaseShelf(row=2, column=4, bookcase=bookcases[2], description="Div languages"),
+        BookcaseShelf(row=3, column=4, bookcase=bookcases[2], description="Typesetting"),
+        BookcaseShelf(row=4, column=4, bookcase=bookcases[2]),
+
+        BookcaseShelf(row=0, column=0, bookcase=bookcases[3]),
+        BookcaseShelf(row=0, column=1, bookcase=bookcases[3]),
+        BookcaseShelf(row=0, column=2, bookcase=bookcases[3]),
+        BookcaseShelf(row=0, column=3, bookcase=bookcases[3]),
+        BookcaseShelf(row=0, column=4, bookcase=bookcases[3]),
+
+        BookcaseShelf(row=0, column=0, bookcase=bookcases[4]),
+        BookcaseShelf(row=0, column=1, bookcase=bookcases[4]),
+        BookcaseShelf(row=0, column=2, bookcase=bookcases[4]),
+        BookcaseShelf(row=0, column=3, bookcase=bookcases[4]),
+        BookcaseShelf(row=0, column=4, bookcase=bookcases[4], description="Religion"),
     ]
 
     with open(Path(__file__).parent.parent / 'data' / 'iso639_1.csv') as f:
@@ -36,7 +121,7 @@ def seed_data(db: SQLAlchemy):
 
     db.session.add_all(media_types)
     db.session.add_all(bookcases)
-    db.session.add_all(locations)
+    db.session.add_all(shelfs)
     db.session.add_all(languages)
     db.session.commit()
-    print("Added test media types, bookcases and locations.")
+    print("Added test media types, bookcases and shelfs.")

worblehat/services/bookcase_item.py

@@ -0,0 +1,45 @@
+import isbnlib
+
+from sqlalchemy import select
+from sqlalchemy.orm import Session
+
+from ..models import (
+    Author,
+    BookcaseItem,
+    Language,
+)
+
+def is_valid_pvv_isbn(isbn: str) -> bool:
+  try:
+      int(isbn)
+  except ValueError:
+      return False
+  return len(isbn) == 8
+
+def is_valid_isbn(isbn: str) -> bool:
+    return any([
+        isbnlib.is_isbn10(isbn),
+        isbnlib.is_isbn13(isbn),
+    ])
+
+def create_bookcase_item_from_isbn(isbn: str, sql_session: Session) -> BookcaseItem | None:
+    metadata = isbnlib.meta(isbn, 'openl')
+    if len(metadata.keys()) == 0:
+        return None
+
+    bookcase_item = BookcaseItem(
+        name = metadata.get('Title'),
+        isbn = int(isbn.replace('-', '')),
+    )
+
+    if len(authors := metadata.get('Authors')) > 0:
+        for author in authors:
+            bookcase_item.authors.add(Author(author))
+
+    if (language := metadata.get('Language')):
+        bookcase_item.language = sql_session.scalars(
+            select(Language)
+            .where(Language.iso639_1_code == language)
+        ).one()
+
+    return bookcase_item

worblehat/services/item.py

@@ -1,31 +0,0 @@
-import isbnlib
-
-from ..models import (
-    Author,
-    BookcaseItem,
-)
-
-def is_valid_isbn(isbn: str) -> bool:
-    return any([
-        isbnlib.is_isbn10(isbn),
-        isbnlib.is_isbn13(isbn),
-    ])
-
-def create_bookcase_item_from_isbn(isbn: str) -> BookcaseItem | None:
-    metadata = isbnlib.meta(isbn)
-    if len(metadata.keys()) == 0:
-        return None
-
-    bookcase_item = BookcaseItem(
-        name = metadata.get('Title'),
-        isbn = int(isbn.replace('-', '')),
-    )
-
-    if len(authors := metadata.get('Authors')) > 0:
-        for author in authors:
-            bookcase_item.authors.add(Author(author))
-
-    if (language := metadata.get('language')):
-        bookcase_item.language = language
-
-    return bookcase_item

worblehat/tools/scanner.py

@@ -1,5 +1,6 @@
 from cmd import Cmd
-from typing import Any, Set
+from typing import Any
+from textwrap import dedent
 
 from sqlalchemy import (
    create_engine,
@@ -9,7 +10,7 @@ from sqlalchemy.orm import (
    Session,
 )
 
-from worblehat.services.item import (
+from worblehat.services.bookcase_item import (
     create_bookcase_item_from_isbn,
     is_valid_isbn,
 )
@@ -43,13 +44,11 @@ class _InteractiveItemSelector(Cmd):
         self,
         cls: type,
         sql_session: Session,
-        items: Set[Any],
         default: Any | None = None,
     ):
         super().__init__()
         self.cls = cls
         self.sql_session = sql_session
-        self.items = items
         self.default_item = default
         if default is not None:
           self.prompt = f'Select {cls.__name__} [{default.name}]> '
@@ -61,13 +60,10 @@ class _InteractiveItemSelector(Cmd):
             self.result = self.default_item
             return True
 
-        if self.sql_session is not None:
         result = self.sql_session.scalars(
             select(self.cls)
             .where(self.cls.name == arg),
         ).all()
-        else:
-            result = [x for x in self.items if x.name == arg]
 
         if len(result) != 1:
             print(f'No such {self.cls.__name__} found: {arg}')
@@ -77,13 +73,10 @@ class _InteractiveItemSelector(Cmd):
         return True
 
     def completenames(self, text: str, *_) -> list[str]:
-        if self.sql_session is not None:
         return self.sql_session.scalars(
             select(self.cls.name)
-                .where(self.cls.name.like(f'{text}%'))
+            .where(self.cls.name.like(f'{text}%')),
         ).all()
-        else:
-            return [x for x in self.items if x.name.startswith(text)]
 
 
 class BookScanTool(Cmd):
@@ -94,13 +87,6 @@ Start by entering a command, or entering an ISBN of a new item.
 Type "help" to see list of commands
     """
 
-    sql_session = None
-
-    bookcases: set[Bookcase] = set()
-    bookcase_locations: set[BookcaseLocation] = set()
-    bookcase_items: set[BookcaseItem] = set()
-    media_types: set[MediaType] = set()
-
     def __init__(self):
         super().__init__()
 
@@ -108,32 +94,39 @@ Type "help" to see list of commands
             engine = create_engine(Config.SQLALCHEMY_DATABASE_URI)
             self.sql_session = Session(engine)
         except Exception:
-            print('Warning: could not connect to database. Saving to database has been disabled.')
+            print('Error: could not connect to database.')
-            return
+            exit(1)
 
-        try:
+        print(f"Connected to database at '{Config.SQLALCHEMY_DATABASE_URI}'")
-             self.bookcases = set(self.sql_session.scalars(select(Bookcase)).all())
-             self.bookcase_locations = set(self.sql_session.scalars(select(BookcaseLocation)).all())
-             self.bookcase_items = set(self.sql_session.scalars(select(BookcaseItem)).all())
-             self.media_types = set(self.sql_session.scalars(select(MediaType)).all())
-        except Exception as e:
-            print(e)
-            print('Warning: could not prefill data from sql database. Saving to database has been disabled.')
-            self.sql_session.close()
-            self.sql_session = None
-            return
-
-        print('Note: Successfully connected to database')
 
 
-    def do_list_bookcases(self, arg: str):
+    def do_list_bookcases(self, _: str):
-        self.columnize([repr(bc) for bc in self.bookcases])
+        """Usage: list_bookcases"""
+        bookcase_shelfs = self.sql_session.scalars(
+            select(BookcaseShelf)
+            .join(Bookcase)
+            .order_by(
+              Bookcase.name,
+              BookcaseShelf.column,
+              BookcaseShelf.row,
+            )
+        ).all()
+
+        bookcase_uid = None
+        for shelf in bookcase_shelfs:
+            if shelf.bookcase.uid != bookcase_uid:
+                print(shelf.bookcase.name)
+                bookcase_uid = shelf.bookcase.uid
+
+            name = f"r{shelf.row}-c{shelf.column}"
+            if shelf.description is not None:
+                 name += f" [{shelf.description}]"
+
+            print(f'  {name} - {sum(i.amount for i in shelf.items)} items')
 
 
     def do_add_bookcase(self, arg: str):
-        """
+        """Usage: add_bookcase <name> [description]"""
-        Usage: add_bookcase <name> [description]
-        """
         arg = arg.split(' ')
         if len(arg) < 1:
             print('Usage: add_bookcase <name> [description]')
@@ -142,82 +135,105 @@ Type "help" to see list of commands
         name = arg[0]
         description = ' '.join(arg[1:])
 
-        if any([bc.name == name for bc in self.bookcases]):
+        if self.sql_session.scalars(
+            select(Bookcase)
+            .where(Bookcase.name == name)
+        ).one_or_none() is not None:
             print(f'Error: a bookcase with name {name} already exists')
             return
 
         bookcase = Bookcase(name, description)
-        self.bookcases.add(bookcase)
-        if self.sql_session is not None:
         self.sql_session.add(bookcase)
 
-
+    def do_add_bookcase_shelf(self, arg: str):
-    def do_list_bookcase_locations(self, arg: str):
+        """Usage: add_bookcase_shelf <bookcase_name> <row>-<column> [description]"""
-        self.columnize([repr(bl) for bl in self.bookcase_locations])
-
-
-    def do_add_bookcase_location(self, arg: str):
-        """
-        Usage: add_bookcase_location <bookcase_name> <name> [description]
-        """
         arg = arg.split(' ')
         if len(arg) < 2:
-            print('Usage: add_bookcase_location <bookcase_name> <name> [description]')
+            print('Usage: add_bookcase_shelf <bookcase_name> <row>-<column> [description]')
             return
 
         bookcase_name = arg[0]
-        name = arg[1]
+        row, column = [int(x) for x in arg[1].split('-')]
         description = ' '.join(arg[2:])
 
-        bookcases_with_name = [bc for bc in self.bookcases if bc.name == bookcase_name]
+        if (bookcase := self.sql_session.scalars(
-        if not len(bookcases_with_name) == 1:
+            select(Bookcase)
+            .where(Bookcase.name == bookcase_name)
+        ).one_or_none()) is None:
             print(f'Error: Could not find bookcase with name {bookcase_name}')
             return
 
-        if any([bc.name == name for bc in self.bookcase_locations]):
+        if self.sql_session.scalars(
-            print(f'Error: a bookcase with name {name} already exists')
+            select(BookcaseShelf)
+            .where(
+              BookcaseShelf.bookcase == bookcase,
+              BookcaseShelf.row == row,
+              BookcaseShelf.column == column,
+            )
+        ).one_or_none() is not None:
+            print(f'Error: a bookshelf in bookcase {bookcase.name} with position {row}-{column} already exists')
             return
 
-        location = BookcaseLocation(
+        shelf = BookcaseShelf(
-            name,
+            row,
-            bookcases_with_name[0],
+            column,
+            bookcase,
             description,
         )
-        self.bookcase_locations.add(location)
+        self.sql_session.add(shelf)
-        if self.sql_session is not None:
-            self.sql_session.add(location)
 
 
-    def do_list_bookcase_items(self, arg: str):
+    def do_list_bookcase_items(self, _: str):
+        """Usage: list_bookcase_items"""
         self.columnize([repr(bi) for bi in self.bookcase_items])
 
 
-    def default(self, arg: str):
+    def default(self, isbn: str):
-        if not is_valid_isbn(arg):
+        isbn = isbn.strip()
-            print(f'"{arg}" is not a valid isbn')
+        if not is_valid_isbn(isbn):
+            print(f'"{isbn}" is not a valid isbn')
             return
 
-        bookcase_item = create_bookcase_item_from_isbn(arg)
+        if (existing_item := self.sql_session.scalars(
-        if bookcase_item == None:
+            select(BookcaseItem)
-            print(f'Could not find data about item with isbn {arg} online.')
+            .where(BookcaseItem.isbn == isbn)
-            print(f'If you think this is not due to a bug, please add the book to openlibrary.org before continuing.')
+        ).one_or_none()) is not None:
+            print('Found existing BookcaseItem:', existing_item)
+            print(f'There are currently {existing_item.amount} of these in the system.')
+            if _prompt_yes_no('Would you like to add another?', default=True):
+                existing_item.amount += 1
+            return
 
-        print('Please select the location where the item is placed:')
+        bookcase_item = create_bookcase_item_from_isbn(isbn, self.sql_session)
-        bookcase_location_selector = _InteractiveItemSelector(
+        if bookcase_item is None:
-            cls = BookcaseLocation,
+            print(f'Could not find data about item with isbn {isbn} online.')
+            print(f'If you think this is not due to a bug, please add the book to openlibrary.org before continuing.')
+            return
+        else:
+            print(dedent(f"""
+            Found item:
+              title: {bookcase_item.name}
+              authors: {', '.join(a.name for a in bookcase_item.authors)}
+              language: {bookcase_item.language}
+            """))
+
+        print('Please select the shelf where the item is placed:')
+        bookcase_shelf_selector = _InteractiveItemSelector(
+            cls = BookcaseShelf,
             sql_session = self.sql_session,
-            items = self.bookcase_locations,
         )
 
-        bookcase_location_selector.cmdloop()
+        bookcase_shelf_selector.cmdloop()
-        bookcase_item.location = bookcase_location_selector.result
+        bookcase_item.shelf = bookcase_shelf_selector.result
 
         print('Please select the items media type:')
         media_type_selector = _InteractiveItemSelector(
             cls = MediaType,
             sql_session = self.sql_session,
-            items = self.media_types,
+            default = self.sql_session.scalars(
-            default = next(mt for mt in self.media_types if mt.name.lower() == 'book'),
+              select(MediaType)
+              .where(MediaType.name.ilike("book")),
+            ).one(),
         )
 
         media_type_selector.cmdloop()
@@ -227,14 +243,16 @@ Type "help" to see list of commands
         if username != '':
             bookcase_item.owner = username
 
-        self.bookcase_items.add(bookcase_item)
-        if self.sql_session is not None:
         self.sql_session.add(bookcase_item)
 
 
-    def do_exit(self, arg: str):
+    def do_exit(self, _: str):
-        # TODO: take internally stored data, and save it, either in csv, json or database
+        """Usage: exit"""
-        raise NotImplementedError()
+        if _prompt_yes_no('Would you like to save your changes?'):
+            self.sql_session.commit()
+        else:
+            self.sql_session.rollback()
+        exit(0)
 
 
 def main():