# 51 SQLAlchemy属性常用数据类型详解 * Integer:整型 * Float:浮点类型 * Boolean:传递True/False进去 * DECIMAL:定点类型，是专门为了解决浮点精度丢失的问题的，在存储相关的字段的时候建议都是要这个数据字段，并且这个类型使用的时候需要传递两个参数，第一个参数使用来标记字段能够存储多少个数字，第二个参数是表示小数点的最大位数 * enum:枚举类型。指定某个字段只能是枚举中指定的几个值，不能为其他值，在ORM模型中，使用Enum来作为枚举，示例代码如下: ```text import enum class TagEnum(enum.Enum): python = "python" flask = "flask" django = "django" class Article(Base): __tablename__ = "article" id = Column(Integer,primary_key=True,autoincrement=True) # tag = Column(Enum('python','django','flask')) tag = Column(Enum(TagEnum)) # article = Article(tag='1') # article = Article(tag='python') article = Article(tag=TagEnum.python) ``` * Date:传递datetime.date\(\)进去。存储时间，只能存储年月日。映射到数据库中是date类型。在python中，可以使用datetime.date来指定 ```text class Article(Base): __tablename__ = "article" id = Column(Integer,primary_key=True,autoincrement=True) create_time = Column(Date) from datetime import date article = Article(create_time=date(year=2017,month=10,day=8)) ``` * DateTime:传递datetime.datetime\(\)进去。存储时间，可以存储年月日时分秒毫秒等。映射到数据库中也是datetime类型。在python代码中，可以使用"datetime.datetime"来指定，示例 ```text class Article(Base): __tablename__ = "article" id = Column(Integer,primary_key=True,autoincrement=True) create_time = Column(DateTime) from datetime import datetime article = Article(create_time=datetime(year=2017,month=11,day=11,hour=11,minute=11,second=11,microsecond=11)) ``` * Time:传递datetime.time\(\)进去。存储时间，可以存储时分秒，映射到数据库中也是time类型。在python代码中，可以使用"datetime.time"来指定，示例\] ```text class Article(Base): __tablename__ = "article" id = Column(Integer,primary_key=True,autoincrement=True) create_time = Column(Time) from datetime import time article = Article(create_time=time(hour=11,minute=11,second=11,microsecond=11)) # article = Article(create_time=datetime.now()) ``` * String:字符类型，使用时需要指定长度，区别于Text类型 * Text:文本类型.存储长字符串，一般可以存储6w多个字符。如果超出了这个范围，可以使用LONGTEXT类型，映射到数据库中就是text类型 * LONGTEXT:长文本类型 ```text from sqlalchemy import create_engine,Column,String,Integer,Float,Boolean,DECIMAL,Enum,Date,DateTime,Time,Text from sqlalchemy.ext.declarative import declarative_base from sqlalchemy.dialects.mysql import LONGTEXT from sqlalchemy.orm import sessionmaker HOSTNAME = '127.0.0.1' PORT = "3306" USERNAME = "root" PASSWORD = "123456" DATABASE = "xt_flask" DB_URI = "mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8".format(USERNAME,PASSWORD,HOSTNAME,PORT,DATABASE) engine = create_engine(DB_URI) Base = declarative_base(engine) session = sessionmaker(engine)() import enum class TagEnum(enum.Enum): python = "python" flask = "flask" django = "django" class Article(Base): __tablename__ = "article" id = Column(Integer,primary_key=True,autoincrement=True) # price = Column(Float) # is_delete = Column(Boolean) # price = Column(DECIMAL(10,4)) # 10000,0001 # tag = Column(Enum('python','django','flask')) # tag = Column(Enum(TagEnum)) # create_time = Column(Date) # create_time = Column(DateTime) # create_time = Column(Time) # title = Column(Text) title = Column(LONGTEXT) # flask-migrate Base.metadata.drop_all() Base.metadata.create_all() # article = Article(price = 10.293) # article = Article(is_delete=True) # article = Article(price=99999.99999) # article = Article(tag='1') # article = Article(tag='python') # article = Article(tag=TagEnum.python) from datetime import date from datetime import datetime from datetime import time # article = Article(create_time=date(year=2017,month=10,day=8)) # article = Article(create_time=datetime(year=2017,month=11,day=11,hour=11,minute=11,second=11,microsecond=11)) # article = Article(create_time=time(hour=11,minute=11,second=11,microsecond=11)) article = Article(title="angle") session.add(article) session.commit() ```