我们从Python开源项目中，提取了以下50个代码示例，用于说明如何使用sqlalchemy.schema.ForeignKeyConstraint()。
def visit_drop_constraint(self, drop): constraint = drop.element if isinstance(constraint, sa_schema.ForeignKeyConstraint): qual = "FOREIGN KEY " const = self.preparer.format_constraint(constraint) elif isinstance(constraint, sa_schema.PrimaryKeyConstraint): qual = "PRIMARY KEY " const = "" elif isinstance(constraint, sa_schema.UniqueConstraint): qual = "INDEX " const = self.preparer.format_constraint(constraint) else: qual = "" const = self.preparer.format_constraint(constraint) return "ALTER TABLE %s DROP %s%s" % \ (self.preparer.format_table(constraint.table), qual, const)
def _mysql_drop_constraint(element, compiler, **kw): """Redefine SQLAlchemy's drop constraint to raise errors for invalid constraint type.""" constraint = element.element if isinstance(constraint, (schema.ForeignKeyConstraint, schema.PrimaryKeyConstraint, schema.UniqueConstraint) ): return compiler.visit_drop_constraint(element, **kw) elif isinstance(constraint, schema.CheckConstraint): raise NotImplementedError( "MySQL does not support CHECK constraints.") else: raise NotImplementedError( "No generic 'DROP CONSTRAINT' in MySQL - " "please specify constraint type")
def _make_foreign_key(params, conn_table): tname = params['referred_table'] if params['referred_schema']: tname = "%s.%s" % (params['referred_schema'], tname) options = params.get('options', {}) const = sa_schema.ForeignKeyConstraint( [conn_table.c[cname] for cname in params['constrained_columns']], ["%s.%s" % (tname, n) for n in params['referred_columns']], onupdate=options.get('onupdate'), ondelete=options.get('ondelete'), deferrable=options.get('deferrable'), initially=options.get('initially'), name=params['name'] ) # needed by 0.7 conn_table.append_constraint(const) return const
def generic_constraint(self, name, table_name, type_, schema=None, **kw): t = self.table(table_name, schema=schema) types = { 'foreignkey': lambda name: sa_schema.ForeignKeyConstraint( [], [], name=name), 'primary': sa_schema.PrimaryKeyConstraint, 'unique': sa_schema.UniqueConstraint, 'check': lambda name: sa_schema.CheckConstraint("", name=name), None: sa_schema.Constraint } try: const = types[type_] except KeyError: raise TypeError("'type' can be one of %s" % ", ".join(sorted(repr(x) for x in types))) else: const = const(name=name) t.append_constraint(const) return const
def url(self): return '{}/{}/{}'.format(osm_api_base, self.osm_type, self.osm_id) # class ItemCandidateTag(Base): # __tablename__ = 'item_candidate_tag' # __table_args__ = ( # ForeignKeyConstraint(['item_id', 'osm_id', 'osm_type'], # [ItemCandidate.item_id, # ItemCandidate.osm_id, # ItemCandidate.osm_type]), # ) # # item_id = Column(Integer, primary_key=True) # osm_id = Column(BigInteger, primary_key=True) # osm_type = Column(osm_type_enum, primary_key=True) # k = Column(String, primary_key=True) # v = Column(String, primary_key=True) # # item_candidate = relationship(ItemCandidate, # backref=backref('tag_table', lazy='dynamic'))
