Question

我使用了一些非常简单的代码来创建一个带有peewee的数据库，我是使用python ORM的新手，所以我无法确定为什么我会收到一大堆错误。这段代码的作用是：首先我创建一个数据库'diary.db' 使用的数据类型是条目（文本字段）和日期（DateTimeField）。我创建了一些函数：'initialize'来运行基本命令并初始化数据库，'menu_loop'将显示一个无限循环的菜单，并且可以调用函数'add_entry'来向数据库添加新条目。

下面是代码：

#!/usr/bin/env python3

from collections import OrderedDict
from peewee import *
import datetime
import sys

db = SqliteDatabase('diary.db')

class Diary(Model):
    entries = TextField()
    date = DateTimeField(default = datetime.datetime.now)
    class Meta:
        database = db

def initialize():
    """initializes the database"""
    db.connect()
    db.create_tables([Diary], safe = True)
#end of initialize

def menu_loop():
    """show menu"""
    choice = 0
    while choice != 2:
        print("Enter '2' to quit")
        print('1) to add an entry')
        choice = input()
        if choice == 1:
            add_entry()
#end of menu_loop

def add_entry():
    """add an entry"""
    print("Enter your entry, press ctrl+d when done")
    data = sys.stdin.read().strip()
    if data:
        while(True):
            option = input('\nSave entry?[1 = yes 0 = no] ')
            if option == 1:
                Diary.create(content=data)
                print ("Saved sucessfully!")
            if option == 0:
                print ("Program exited")
                break;
#end of add_entry

if __name__ == '__main__':
    initialize()
    menu_loop()

和错误日志

Enter '2' to quit
1) to add an entry
1
Enter your entry, press ctrl+d when done
this is my new entry
hello world^D
Save entry?[1 = yes 0 = no] 1
Traceback (most recent call last):
  File "ispythonsmart.py", line 50, in <module>
    menu_loop()
  File "ispythonsmart.py", line 30, in menu_loop
    add_entry()
  File "ispythonsmart.py", line 41, in add_entry
    Diary.create(content=data)
  File "/Library/Python/2.7/site-packages/peewee.py", line 4494, in create
    inst.save(force_insert=True)
  File "/Library/Python/2.7/site-packages/peewee.py", line 4680, in save
    pk_from_cursor = self.insert(**field_dict).execute()
  File "/Library/Python/2.7/site-packages/peewee.py", line 3213, in execute
    cursor = self._execute()
  File "/Library/Python/2.7/site-packages/peewee.py", line 2628, in _execute
    return self.database.execute_sql(sql, params, self.require_commit)
  File "/Library/Python/2.7/site-packages/peewee.py", line 3461, in execute_sql
    self.commit()
  File "/Library/Python/2.7/site-packages/peewee.py", line 3285, in __exit__
    reraise(new_type, new_type(*exc_args), traceback)
  File "/Library/Python/2.7/site-packages/peewee.py", line 3454, in execute_sql
    cursor.execute(sql, params or ())
peewee.IntegrityError: NOT NULL constraint failed: diary.entries

Answer 1

您需要将条目设置为null=True或使用条目的默认值：

class Diary(Model):
    entries = TextField(null=True)

输出：

Enter '2' to quit
1) to add an entry
1
Enter your entry, press ctrl+d when done
foobar

Save entry?[1 = yes 0 = no] 1
Saved successfully!

您希望在数据库中看到"entries" TEXT而不是"entries" TEXT NOT NULL。如果列设置为NOT NULL，则必须插入值，否则将出现完整性错误，另一种方法是为列提供默认值，即TextField(default="foo")。在旁注中，你有#!/usr/bin/env python3作为你的shebang，但你的代码是为python 2编写的，所以你可能想要纠正它。

使用peewee execute_sql self.commit（）创建数据库

1 个答案: