Peewee基本使用

• Peewee 即 Python OMR 框架之一。

peewee安装&配置

通过 pip instll peewee
新建 models.py 模型文件
在 models.py 中加入以下基础代码
运行 models.py，在 mysql 中生成 new_record 表

peewee使用

from peewee import *
from settings import DATABASES

//  连接数据库
MYSQL_DB = MySQLDatabase(
   host=DATABASES['DEFAULT']['HOST'],
   port=DATABASES['DEFAULT']['PORT'],
   user=DATABASES['DEFAULT']['USER'],
   passwd=DATABASES['DEFAULT']['PASSWORD'],
   database=DATABASES['DEFAULT']['NAME'],
)

class BaseModel(Model):
   """基础模型类"""

   class Meta:
       database = MYSQL_DB

class NewRecord(BaseModel):
   # 所有model都继承基类model

   field_1 = CharField(max_length=10, null=True)

   class Meta:
       db_table = 'new_record'

if __name__ == '__main__':
   # 创建表
   NewRecord.create_table()

查询

new_records = NewRecord.select().where(
        NewRecord.field_1 == "").order_by(
        NewRecord.id)

注意：查询条件之间的关系不是用 and 和 or 的逻辑运算符，而是用 & 和 |

查询单条数据

# 若查询不到记录会报错
_record = NewRecord.get(NewRecord.field_1 == field_1 and NewRecord.field_2 == field_2)  
print(_record.field_1, _record.field_2)

删除

NewRecord.delete().where(NewRecord.field_1 == field_1).execute()

删除单条数据

_record = NewRecord.get(NewRecord.field_1 == field_1 and NewRecord.field_2 == field_2)
_record.delete_instance()

联合约束

class Meta:
        db_table = 'new_record'
        constraints = [SQL('UNIQUE KEY(field_1, field_2)')]

默认时间

class NewRecord(BaseModel):
    """NewRecord 模型类"""
    # ...
	add_time = DateTimeField(datetime.datetime.now)

	class Meta:
        db_table = 'new_record'

根据数据表生成model

python -m pwiz -e mysql -H {主机地址} -p 3306  -u root -- password   {数据库名称} > {生成的代码文件 例model.py}

查询操作符 & 逻辑运算符

符号	注释
==	x equals y
<	x is less than y
<=	x is less than or equal to y
>	x is greater than y
>=	x is greater than or equal to y
!=	x not equals y
<<	x IN y,where is a list or equal
>>	x IS y,where is a None/NULL
%	x LIKE y where y may conta