def _init_db(self, engine):
"""Connect to database and create tables.
Parameters
----------
txn : sa.engine.Connection, optional
The transaction to execute in. If this is not provided, a new
transaction will be started with the engine provided.
Returns
-------
metadata : sa.MetaData
The metadata that describes the new asset db.
"""
with ExitStack() as stack:
# if txn is None:
txn = stack.enter_context(engine.connect())
tables_already_exist = self._all_tables_present(txn)
# Create the SQL tables if they do not already exist.
if not tables_already_exist:
metadata.create_all(txn, checkfirst=True)
# 将table
metadata.reflect(only=asset_db_table_names)
for table_name in asset_db_table_names:
setattr(self, table_name, metadata.tables[table_name])
def _init_db(self, txn=None):
"""Connect to database and create tables.
Parameters
----------
txn : sa.engine.Connection, optional
The transaction to execute in. If this is not provided, a new
transaction will be started with the engine provided.
Returns
-------
metadata : sa.MetaData
The metadata that describes the new asset db.
"""
with ExitStack() as stack:
if txn is None:
txn = stack.enter_context(self.engine.begin())
tables_already_exist = self._all_tables_present(txn)
if not tables_already_exist:
# Create the SQL tables if they do not already exist.
metadata.create_all(txn, checkfirst=True)
def _init_db(self, engine):
"""Connect to database and create tables.
with ExitStack() as stack:
由于已注册的回调是按注册的相反顺序调用的，因此最终行为就好像with 已将多个嵌套语句与已注册的一组回调一起使用。
这甚至扩展到异常处理-如果内部回调抑制或替换异常，则外部回调将基于该更新状态传递自变量。
enter_context 输入一个新的上下文管理器，并将其__exit__()方法添加到回调堆栈中。返回值是上下文管理器自己的__enter__()方法的结果。
callback（回调，* args，** kwds ）接受任意的回调函数和参数，并将其添加到回调堆栈中。
stack.callback(on_exit())
stack.enter_context(ZiplineAPI(self.algo))
Parameters
----------
txn : sa.engine.Connection, optional
The transaction to execute in. If this is not provided, a new
transaction will be started with the engine provided.
Returns
-------
metadata : sa.MetaData
The metadata that describes the new asset db.
"""
with ExitStack() as stack:
# if txn is None:
txn = stack.enter_context(engine.connect())
tables_already_exist = self._all_tables_present(txn)
# Create the SQL tables if they do not already exist.
if not tables_already_exist:
metadata.create_all(txn, checkfirst=True)
# 将table
metadata.reflect(only=asset_db_table_names)
for table_name in asset_db_table_names:
setattr(self, table_name, metadata.tables[table_name])
# 融券余额
sa.Column('rqye', sa.Numeric(15, 8), nullable=False),
extend_existing=True)
# 版本
version_info = sa.Table(
'version_info',
metadata,
sa.Column('id', sa.Integer, default=0, autoincrement=True),
sa.Column(
'version',
sa.Integer,
unique=True,
nullable=False,
),
# This constraint ensures a single entry in this table
sa.CheckConstraint('id <= 1'),
extend_existing=True)
asset_db_table_names = frozenset(
['asset_router', 'equity_status', 'equity_basics', 'convertible_basics'])
metadata.create_all(bind=engine)
__all__ = [
'm_cap', 'holder', 'unfreeze', 'massive', 'ownership', 'fund_price',
'version_info', 'asset_router', 'equity_status', 'equity_basics',
'equity_price', 'equity_splits', 'equity_rights', 'convertible_basics',
'convertible_price', 'asset_db_table_names'
]