MySQL 唯一约束（Unique Key）是指所有记录中字段的值不能重复出现。MySQL中的唯一约束是一种用于确保表...
# access the column "employee_id": employees.columns.employee_id # or just employees.c.employee_id # via string employees.c["employee_id"] # a tuple of columns may be returned using multiple strings # (new in 2.0) emp_id, name, type = employees.c["employee_id", "name", "type"]...
b = association_proxy("b_rel","value", creator=lambdax: B(value=x))classB(Base): __tablename__ ="test_b"__table_args__ = (UniqueConstraint("a_id","value"),)id= Column(Integer, primary_key=True) a_id = Column(Integer, ForeignKey("test_a.id"), nullable=False) value = Colu...
用法与operate()相同。 attribute columns_to_assign method declarative_scan(decl_scan: _ClassScanMapperConfig, registry: _RegistryType, cls: Type[Any], originating_module: str | None, key: str, mapped_container: Type[Mapped[Any]] | None, annotation: _AnnotationScanType | None, extracted_mappe...
#创建单表 #!/usr/bin/env python # -*- coding:utf-8 -*- import datetime from sqlalchemy import create_engine from sqlalchemy.ext.declarative import declarative_base from sqlalchemy import Column, Integer, String, Text, ForeignKey, DateTime, UniqueConstraint, Index Base = declarative_base() ...
init(), add_is_dependent_on(), alias(), append_column(), append_constraint(), argument_for(), autoincrement_column, c, columns, compare(), compile(), constraints, corresponding_column(), create(), delete(), description, dialect_kwargs, dialect_options, drop(), entity_namespace, ...
Fixed ORM regression where the new behavior of “eager loaders run on unexpire” added in#1763would lead to loader option errors being raised inappropriately for the case where a singleQueryorSelectwere used to load multiple kinds of entities, along with loader options that apply to just one ...
columns参数 name参数也可以当作位置参数,需放在第1个位置,位置传参。 title= Column(String(50),name='my_title',nullable=False) title2=Column("title_2",String(20),nullable=True) 1. 2. 3. query可用参数: 模型对象。指定查找这个模型中所有的对象。
that aliased construct appeared multiple times in a single statement. References:#12364 sql [sql] [bug]Added new parametersAddConstraint.isolate_from_tableand DropConstraint.isolate_from_table, defaulting to True, which both document and allow to be controllable the long-standing behavior of ...
Parameters:ident– A scalar or tuple value representing the primary key. For a composite primary key, the order of identifiers corresponds in most cases to that of the mappedTableobject’s primary key columns. For amapper()that was given theprimary keyargument during construction, the order of...