SQLAlchemy操作MariaDB笔记之五

多表查询

手动连接

for uname,email_address in session.query(User.fullname,Address.email_address).filter(User.id==Address.user_id,User.name=="jack"):     print uname    print email_address 

自然连接

>>> session.query(User).join(Address).\...         filter(Address.email_address=='[e-mail]').\...         all() [<User(name='jack', fullname='Jack Bean', password='gjffdd')>]

指定连接方式

query.join(Address, User.id==Address.user_id)    # explicit conditionquery.join(User.addresses)                       # specify relationship from left to rightquery.join(Address, User.addresses)              # same, with explicit targetquery.join('addresses')                          # same, using a string

外连接

query.outerjoin(User.addresses)   # LEFT OUTER JOIN