NOT NULL約束失敗，但字段不爲空

Question

我正在嘗試使用我的Web窗體添加一個新項目。

但我得到這個錯誤。雖然我從打印聲明中驗證了電子郵件，但它並非空白。

在該行

File "/Users/j/udacity/item_catalog/item-catalog-190/application.py", line 131, in newItem 
    session.commit() 


IntegrityError: (sqlite3.IntegrityError) NOT NULL constraint failed: category.email [SQL: u'INSERT INTO category (name, email) VALUES (?, ?)'] [parameters: (u'Pilates', None)] 


@app.route('/catalog/new', methods=['GET','POST']) 
def newItem(): 
    if request.method == 'POST': 
     placeholder=request.form['category'] 
     category = Category(name=placeholder) 
     print "**********", login_session['email'] 
     email = login_session['email'] 
     newThing = Item(name=request.form['name'], description=request.form['description'], price=request.form['price'],category=category, email=email) 
     session.add(newThing) 
     session.commit() 
     return redirect('/catalog') 
    else: 
     return render_template('newitem.html') 

這些是我的兩個表。

class Item(Base): 
__tablename__ = 'item' 

name = Column(String(80), nullable=False) 
id = Column(Integer, primary_key=True) 
description = Column(String(250)) 
price = Column(String(8)) 
category_id = Column(Integer, ForeignKey('category.id')) 
email = Column(String(250),nullable=False) 
category = relationship(Category) 


class Category(Base): 
__tablename__ = 'category' 

id = Column(Integer, primary_key=True) 
name = Column(String(250), nullable=False) 
email = Column(String(250), nullable=False) 

Answer 1

你category表需要email場是NOT NULL，當你創建一個新的類別：

category = Category(name=placeholder) 

的email字段的默認值是NULL。

這是INSERT查詢：

SQL: u'INSERT INTO category (name, email) VALUES (?, ?)'] [parameters: (u'Pilates', None) 

正如你所看到的，第二paramenter（這是email）是無（這相當於null在SQL

你可能想。改變你的代碼：

if request.method == 'POST': 
    placeholder=request.form['category'] 
    email = login_session['email'] # moved the email here 
    print "**********", login_session['email'] 
    category = Category(name=placeholder, email=email) # here you have the email variable so you can use it