On Tue, Sep 08, 2009 at 13:06 +0200, Wolodja Wentland wrote: > is it possible to drop primary key indexes from within SA? I already > found the table.indexes set, but it does not contain the primary key > index. I can therefore drop all indexes for a table except the primary > key one.
I did some investigation and found that the primary key index is
generated automagically by PostgreSQL rather than SA. This is because i
declare some columns with 'primary_key=True' which causes psql to create
a primary key constraint and an index.
If i connect to the db in question and reflect the tables it is
unfortunately not possible to drop any pkey constraint, because the
.drop() method if not present in sa.schema.PrimaryKeyConstraint but only
in migrate.changeset.constraint.PrimaryKeyConstraint.
I create all PrimaryKeyConstraints explicitly now and use the
PrimaryKeyConstraint class from migrate. The problem i am facing now is
that i do not get instances of migrate's PrimaryKeyConstraint but rather
SA's one if i work on the constraints like exemplified in the following
code snippet:
--- snip ---
...
metadata = MetaData()
metadata.bind = engine
self._metadata.reflect()
tbl = self._metadata.tables[table_name]
pkc = [ con for con in tbl.constraints
if isinstance(con, PrimaryKeyConstraint) ][0]
log.debug('Primary key constraint for table [%s] on: %s'%(
table_name, pkc.columns.keys()))
log.debug('Dropping pkey constraint ...')
pkc.drop()
^^^^^^^^^^ This method is not present because i get instances from SA's classes
not migrate's
--- snip ---
How can i tackle this problem? Any advise is welcome!
with kind regards
Wolodja Wentland
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