Hi all,
I'm building a python (ver:2.7) app with MySQL as the backend db and
sqlalchemy as the handler. I'm new to sqlalchemy module.
I'm trying to execute raw SQL code through my python. The reason is I want
to change the `id` of a table, which is not the primary key, to be
auto_incremented; a thing that is not supported for MySQL through
sqlalchemy .
The code looks like this :
#creation of 2 tables, Applications and Api_Calls
metadata = MetaData(bind=self.engine)
self.app_table = self.Applications()
self.apicall_table = self.Api_Calls()
self.base.metadata.create_all(self.engine)
#the problematic part
auto_incr = text("""ALTER TABLE `table`.`Applications` DROP PRIMARY KEY,
ADD UNIQUE KEY(id);
ALTER TABLE `Applications` ADD PRIMARY KEY(md5); """ )
nengine = create_engine('mysql+mysqldb://root:1122@localhost/Database' ,
echo = True)
self.engine = nengine
self.engine.execute(auto_incr)
Some clarification : i'm creating a new engine 'nengine' cause the previous
one is created before the creatin of 'Database' schema. Then the new engine
is assigned to 'self.engine'. The weird thing is that when I run the
application for the first time, I get no errors. When I issue a DROP
DATABASE and restart the application , I get the 2014 error. My python app
doesn't support threads .Moreover, I want to execute the SQL query for
multiple tables , which will look smthng like :
with self.engine.connect() as con:
for line in data:
text("""ALTER TABLE `%s` DROP PRIMARY KEY, ADD UNIQUE KEY(%s);
TABLE `Applications` ADD PRIMARY KEY(%s); """ %(line['table'] ,
line['id'], line['key']))
con.execute(auto_incr)
As i've understand be searching for this issue, there is a problem in
concurrency and it's SQL fault.
How should I deal with the error ?
I've already searched the group but didn't find a suitable answer.
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
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