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Python SQLAlchemy Basics Working with SQLAlchemy Create and Read Books

Jonathan Grieve
MOD
Jonathan Grieve
Treehouse Moderator 90,666 Points

TypeError: str is not callable

Morning all. :)

Okay, so I'm having a lot of trouble adding a new record to the SQLAlchemy DB.

Admittedly I've made some minor changes to the code, branching out the scope of the project to "Media" rather than just books and added a couple of new fields.

I actually managed it once, adding the data but all the records came up as null. I think that was because I didn't pass anything in to Media() to the choice 1 code block. After I did that, I've been hitting a TypeError exception and nothing I've tried has fixed it.

This particular error seems to be a particular case that I'm calling a string as a function that therefore nothing can be done with it.

app.py
# import models
from models import (Base, session, Media, engine)

# application imports 
import datetime
import csv


# To display the menu options to the console
def menu():
    while True:
        print('''
            \nMEDIA LIBRARY MENU
            \r1) Add Item
            \r2) View All Books
            \r3) Search Media Item
            \r4) Media Item
            \r5) Exit the Application ''') 

        # store a variable for the menu choice
        choice = input('What would you like to do? ')
        if choice in ['1','2','3','4','5']:
            return choice
        else:
            input('''
                    \rError: Please try again with one of the choices above
                    \rA number from 1 to 5.
                    \rPress Enter to Try Again. ''')


# date field data cleaning and type conversion
def clean_date(date_string):

    months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']

    # split and convert date format into usable data
    split_date = date_string.split(" ")
    print(split_date)

    try:

        # convert date digits to integer objects
        month = int(months.index(split_date[0]) + 1)
        day = int(split_date[1].split(',')[0])
        year = int(split_date[2])

        print(day)
        print(month)
        print(year)

        return_date = datetime.date(year, month, day)

    except ValueError:
        input("""
        \n*******eError message. invalid date format:    
        \nUse date format: February 22, 2021
        \n*******
        """)
        return

    else: 
        return return_date


# price field - conversion to integer data type
def clean_price(price_str):

    try:        
        price_float = float(price_str)

    except ValueError:
        input("""Error: price format

        \n\nPrice Format Example: $00.00
        """)

    else:

        # print(price)
        return int(price_float * 100)



# import 
def import_csv():
    with open('media_list.csv') as csvfile:
        data = csv.reader(csvfile)

        # display data in the console
        for row in data:
            print(row)

            media_title = row[0]
            media_type = row[1]
            artist = row[2]
            genre = row[3]
            published_date = clean_date(row[4])
            price = clean_price(row[5])


            new_media = Media(
                media_title=media_title,            
                media_type=media_type, 
                artist=artist, 
                genre=genre, 
                published_date=published_date, 
                price=price
            )

            session.add(new_media)
            session.commit()


# To keep the application running until user exit
def app():

    app_running = True

    while app_running:

        choice = menu()

        if choice == '1':

            # add book/media
            title=input('Media Title:  ')
            type=input('Media Type:  ')
            author=input('Media Author: ')
            genre=input('Genre: ')


            date_error = True
            while date_error:
                date = input('Published Date (Exmp) ')
                date = clean_date(date)

                if type(date) == datetime.date:
                    date_error = False 


            price_error = True
            while price_error:
                price = input('Price (Exmp) ')
                price = clean_price(price)

                if type(price) == int:
                    price_error = False


            # add data to db
            new_media_add = Media(
                media_title=title,            
                media_type=type, 
                artist=author, 
                genre=genre, 
                date=date, 
                price=price
            )

            session.add(new_media_add)
            session.commit()


        elif choice == '2':
            # view book 
            pass

        elif choice == '3':
            # view book 
            pass

        elif choice == '4':
            # analyse - media item details
            pass

        else:             
            # default option to exit the application 
            print('\n\nGOODBYE')
            app_running = False


# Create the Database
if __name__  == '__main__':
    Base.metadata.create_all(engine)

    # call app functions
    # clean_date("June 28, 2021")
    # clean_price("33.33")
    # import_csv()
    app()

    for media in session.query(Media):
        print(media)
models.py
## create a database

# Declare the imports
from sqlalchemy import (create_engine, Column, Integer, String, Date)
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker


## create a model

# Setup DB for creation
engine = create_engine('sqlite:///media.db', echo=False)
Session = sessionmaker(bind=engine)
session = Session()
Base = declarative_base()


# Setup the database schema  media_ title, author, date published, price
class Media(Base):
    __tablename__ = 'media'

    id= Column(Integer, primary_key=True)
    media_title = Column('Media Title', String)
    media_type = Column('Media Type', String)
    artist = Column('Author/Creator', String)
    genre = Column('Genre', String)
    published_date = Column('Published', Date)
    price = Column('Price', Integer)

    # Display string of data in console - formatted string
    def __repr__(self):
        return f'\n\nMedia Title: {self.media_title} \nMedia Type: {self.media_type} \nArtist: {self.artist} \nGenre: {self.genre} \nPublished Date: {self.published_date} \nPrice: {self.price}' 

1 Answer

Jonathan Grieve
Jonathan Grieve
Treehouse Moderator 90,666 Points

Thanks for that but I don't think that's quite the issue. I should have specified the stacktrace

Traceback (most recent call last):
  File "C:\<snip>\python\flask\sqlalchemy\cli_app\app.py", line 190, in <module>
    app()
  File "C:\<snip>python\flask\sqlalchemy\cli_app\app.py", line 137, in app
    if type(date) == datetime.date:
TypeError: 'str' object is not callable

It seems to be an issue with the datetime object

Megan Amendola
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Megan Amendola
Treehouse Teacher

Ah ok I think I see what happened. Inside of your app function towards the top, you created a variable called 'type' which is overriding the python type function so it's no longer a function and is instead a string.

# add book/media
    title=input('Media Title:  ')
    # change the variable name here
    type=input('Media Type:  ')
Jonathan Grieve
Jonathan Grieve
Treehouse Moderator 90,666 Points

Thanks Megan, that did the trick. 😀

I guess I should have stuck to my guns when I googled the error. What I researched was exactly what was happening. The trouble is it's so much harder to spot when there aren't actually any syntax errors