mysql: using aiomysql.

from Aiopony import *

db = AioDatabase()


async def init_db(config):
   db_host = "127.0.0.1"
   db_user = "root"
   db_password = "123456"
   db_name = "data"
   await db.bind('mysql', host=db_host, user=db_user, passwd=db_password, db=db_name)
   await db.generate_mapping(create_tables=True)
   
class Student(db.Entity):
   _table_ = "Students"
   record = PrimaryKey(int)
   name = Required(unicode, column="fio")
   group = Required("Group")
   scholarship = Required(int, default=0)
   marks = Set("Mark")


class Group(db.Entity):
   _table_ = "Groups"
   number = PrimaryKey(str)
   department = Required(int)
   students = Set("Student")
   subjects = Set("Subject")


class Subject(db.Entity):
   _table_ = "Subjects"
   name = PrimaryKey(unicode)
   groups = Set("Group")
   marks = Set("Mark")


class Mark(db.Entity):
   _table_ = "Exams"
   student = Required(Student, column="student")
   subject = Required(Subject, column="subject")
   value = Required(int)
   PrimaryKey(student, subject)
   


@db_session()
async def populate_db():
   Physics = Subject(name='Physics')
   Chemistry = Subject(name='Chemistry')
   Math = Subject(name='Math')

   g3132 = Group(number='3132', department=33, subjects=[Physics, Math])
   g4145 = Group(number='4145', department=44, subjects=[Physics, Chemistry, Math])
   g4146 = Group(number='4146', department=44)

   s101 = Student(record=101, name='Bob', group=g4145, scholarship=0)
   s102 = Student(record=102, name='Joe', group=g4145, scholarship=800)
   s103 = Student(record=103, name='Alex', group=g4145, scholarship=0)
   s104 = Student(record=104, name='Brad', group=g3132, scholarship=500)
   s105 = Student(record=105, name='John', group=g3132, scholarship=1000)

   Mark(student=s101, subject=Physics, value=4)
   Mark(student=s101, subject=Math, value=3)
   Mark(student=s102, subject=Chemistry, value=5)
   Mark(student=s103, subject=Physics, value=2)
   Mark(student=s103, subject=Chemistry, value=4