def __init__(self,
config,
minconn=5,
maxconn=10,
key='defalut',
adapter='mysql'):
""" Setup DB::
param config dict: is the db adapter config
param key string: the key to identify dabtabase
param adapter string: the dabtabase adapter current support mysql only
param minconn int: the min connection for connection pool
param maxconn int: the max connection for connection pool
"""
adapter = adapter or 'mysql'
self.key = key
self.adapter = adapter
self.pool = ConnectionPool(minconn, maxconn,
self.connection_class(adapter), config)
self.dialect = self.dialect_class(adapter)(self)
