I have been researching how to insert a list of ~500 tuples (rows) that has 7 elements (columns) into a database. I have read through various posts on stackoverflow as well as other forums. I found the following and it suggests to use the 'executemany()' method but its not so clear to me how. Do I need to covert my object from tuple to a dictionary? The problem is I don't have a name:value type of data structure.
How to use SQLAlchemy to dump an SQL file from query expressions to bulk-insert into a DBMS?
Here is an example:
engine = create_engine('sqlite:///:memory:', echo=True)
metadata = MetaData()
hockey= Table('hockey', metadata,
Column('team', String(16), primary_key=True),
Column('jersey_colour', String(16)),
Column('stadium', String(32)),
Column('goals', Integer),
Column('date', Date, primary_key=True),
Column('assists', Integer))
>>>data[0]
[(u'Maple Leafs', u'Blue', u'Air Canada Center', 151, '2013-03-25', 301)]
Edit:
I tried the solution described (Sqlalchemy core, insert multiple rows from a tuple instead of dict) as follows:
markers = ','.join('?' * len(data[0]))
ins = 'INSERT INTO {tablename} VALUES ({markers})'
ins = ins.format(tablename=hockey.name, markers=markers)
>>str(ins)
'INSERT INTO hockey VALUES (?,?,?,?,?,?)'
conn = engine.connect()
result = conn.execute(ins, data)
In [59]: result = conn.execute(ins, data)
2013-03-26 07:29:28,371 INFO sqlalchemy.engine.base.Engine INSERT INTO hockey VALUES (?,?,?,?,?,?)
2013-03-26 07:29:28,371 INFO sqlalchemy.engine.base.Engine (u'Maple Leafs', u'Blue', u'Air Canada Center', 151, '2013-03-25', 301)
2013-03-26 07:29:28,371 INFO sqlalchemy.engine.base.Engine ROLLBACK
---------------------------------------------------------------------------
OperationalError Traceback (most recent call last)
<ipython-input-59-dafe2aef2c66> in <module>()
----> 1 result = conn.execute(ins, data)
/usr/lib/python2.7/site-packages/sqlalchemy/engine/base.pyc in execute(self, object, *multiparams, **params)
662 object,
663 multiparams,
--> 664 params)
665 else:
666 raise exc.InvalidRequestError(
/usr/lib/python2.7/site-packages/sqlalchemy/engine/base.pyc in _execute_text(self, statement, multiparams, params)
806 statement,
807 parameters,
--> 808 statement, parameters
809 )
810 if self._has_events:
/usr/lib/python2.7/site-packages/sqlalchemy/engine/base.pyc in _execute_context(self, dialect, constructor, statement, parameters, *args)
876 parameters,
877 cursor,
--> 878 context)
879 raise
880
/usr/lib/python2.7/site-packages/sqlalchemy/engine/base.pyc in _execute_context(self, dialect, constructor, statement, parameters, *args)
869 statement,
870 parameters,
--> 871 context)
872 except Exception, e:
873 self._handle_dbapi_exception(
/usr/lib/python2.7/site-packages/sqlalchemy/engine/default.pyc in do_execute(self, cursor, statement, parameters, context)
318
319 def do_execute(self, cursor, statement, parameters, context=None):
--> 320 cursor.execute(statement, parameters)
321
322 def do_execute_no_params(self, cursor, statement, context=None):
OperationalError: (OperationalError) near "hockey": syntax error 'INSERT INTO hockey VALUES (?,?,?,?,?,?)' (u'Maple Leafs', u'Blue', u'Air Canada Center', 151, '2013-03-25', 301)
There error:
OperationalError: (OperationalError) near "hockey": syntax error 'INSERT INTO hockey VALUES (?,?,?,?,?,?)' (u'Maple Leafs', u'Blue', u'Air Canada Center', 151, '2013-03-25', 301)
Well I did the following:
column_names = tuple(c.name for c in hockey.c)
>>>column_names
('team', 'jersey_colour', 'stadium', 'goals', 'date', 'assists')
final = [dict(zip(column_names,x)) for x in data]
The above creates a list of dictionaries for each or the rows. This should work but when I run I get the following error:
>>>conn.execute(ins, final)
SQLite Date type only accepts Python date objects as input.
In any case this is another problem that I need to look into. That said, I am answering and accepting this question because the above dictionary should work.
来源：https://stackoverflow.com/questions/15628131/python-sqlalchemy-insert-multiple-lines-in-a-tuple-data-structure