caption= Column(String(50), default='篮球')def__str__(self):returnself.captionclassPerson(Base):__tablename__='person'id= Column(Integer, primary_key=True) name= Column(String(32), index=True, nullable=True)#hobby指的是tablename而不是类名,uselist=Falsehobby_id = Column(Integer, Foreig...
id = Column(Integer, primary_key=True) caption = Column(String(50), default='篮球') class Person(Base): __tablename__ = 'person' id = Column(Integer, primary_key=True) name = Column(String(32), index=True, nullable=True) # hobby指的是tablename而不是类名 # 关联字段写在多的一方,...
from sqlalchemy.schema import DDLElement from sqlalchemy.ext.compiler import compiles class AlterColumn(DDLElement): def __init__(self, column, cmd): self.column = column self.cmd = cmd @compiles(AlterColumn) def visit_alter_column(element, compiler, **kw): return "ALTER TABLE %s ALTER ...
email = db.Column(db.String(120), unique=True) age = db.Column(db.Integer, default=0) created_at = db.Column(db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow) 在上述示例中,我们使用了常用的列选项,如`primary_key`、`nullable`、`unique`、`default`和`onupdate`来配置User模型...
value = db.Column(db.String(50), nullable=True, comment='标签') annotated_amount = db.Column(db.Integer, autoincrement=False, nullable=True, comment='标记数量') created_at = db.Column(db.DateTime, nullable=True, comment='创建时间') ...
SQLAlchemy - Column详解Column常用参数:default:默认值nullable:是否可有primary_key:是否 sqlalchemy 最小值 数据类型 sqlalchemy模块 sqlalchemy详解 SQLAlchemy一、 什么是SQLAlchemy?SQLAlchemy是Python一款非常强大的ORM软件。对象关系映射(Object Relational Mapping,简称ORM)是通过使用描述对象和数据库之间映射的元数...
session.commit() # INSERT with the 'data' column omitted; the database # itself will persist this as the NULL value 在INSERT 中省略一列意味着该列将设置为 NULL 值,除非该列设置了默认值,此时默认值将被保留。这既适用于纯 SQL 角度的服务器端默认值,也适用于 SQLAlchemy 在客户端和服务器端默认...
viewonly=True,)class Task(Base):__tablename__ = "task"id: Mapped[int] = mapped_column(primary_key=True)user_account_id: Mapped[int] = mapped_column(ForeignKey("user_account.id"))description: Mapped[str | None]task_date: Mapped[datetime.datetime] = mapped_column(server_default=func.now...
function sqlalchemy.orm.synonym(name: str, *, map_column: bool | None = None, descriptor: Any | None = None, comparator_factory: Type[PropComparator[_T]] | None = None, init: _NoArg | bool = _NoArg.NO_ARG, repr: _NoArg | bool = _NoArg.NO_ARG, default: _NoArg | _T =...
有一个用例是为了在对象持久化之前,使得 Python 中的值与 Core 生成的默认值对应。为了适应这种用例,添加了一个新的事件AttributeEvents.init_scalar()。在 属性仪器化 中的新示例active_column_defaults.py说明了一个示例用法,因此效果可以是: >>>obj = MyObj()>>>obj.some_value"my default" ...