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Code Issues 32 Releases Wiki Activity

[multi-db] Added postgresql-specific SchemaBuilder subclass that includes method for sequence resets.

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git-svn-id: http://code.djangoproject.com/svn/django/branches/multiple-db-support@3442 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Jason Pellerin 2006-07-25 00:45:43 +00:00
parent 14f8c83827
commit 6c65e612b4
1 changed files with 41 additions and 0 deletions
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41
django/db/backends/postgresql/sql.py Normal file
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from django.db import models
from django.db.backends.ansi.sql import BoundStatement, SchemaBuilder, \
default_style
class PgSchemaBuilder(SchemaBuilder):
"""SchemaBuilder for postgres. Implements an additional method that
outputs SQL statements to reset the sequence(s) for a model.
"""
def get_sequence_reset(self, model, style=None):
"""Get sequence reset sql for a model.
"""
if style is None:
style=default_style
for f in model._meta.fields:
output = []
db = model._default_manager.db
connection = db.connection
qn = db.backend.quote_name
if isinstance(f, models.AutoField):
output.append(BoundStatement(
"%s setval('%s', (%s max(%s) %s %s));" % \
(style.SQL_KEYWORD('SELECT'),
style.SQL_FIELD('%s_%s_seq' %
(model._meta.db_table, f.column)),
style.SQL_KEYWORD('SELECT'),
style.SQL_FIELD(qn(f.column)),
style.SQL_KEYWORD('FROM'),
style.SQL_TABLE(qn(model._meta.db_table))),
connection))
break # Only one AutoField is allowed per model, so don't bother continuing.
for f in model._meta.many_to_many:
output.append(
BoundStatement("%s setval('%s', (%s max(%s) %s %s));" % \
(style.SQL_KEYWORD('SELECT'),
style.SQL_FIELD('%s_id_seq' % f.m2m_db_table()),
style.SQL_KEYWORD('SELECT'),
style.SQL_FIELD(qn('id')),
style.SQL_KEYWORD('FROM'),
style.SQL_TABLE(f.m2m_db_table())),
connection))
return output