尝试在Django 1.9中迁移 - 奇怪的SQL错误“django.db.utils.OperationalError：near”）“：语法错误”

Question

I don't have a clue what's causing this error. It appears to be a bug that there isn't a fix for. Could anyone tell give me a hint as to how I might get around this? It's frustrating me to no end. Thanks.

Operations to perform:
  Apply all migrations: admin, contenttypes, optilab, auth, sessions
Running migrations:
  Rendering model states... DONE
  Applying optilab.0006_auto_20160621_1640...Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line 353, in execute_from_command_line
    utility.execute()
  File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line 345, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Python27\lib\site-packages\django\core\management\base.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Python27\lib\site-packages\django\core\management\base.py", line 399, in execute
    output = self.handle(*args, **options)
  File "C:\Python27\lib\site-packages\django\core\management\commands\migrate.py", line 200, in handle
    executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
  File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 92, in migrate
    self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 121, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 198, in apply_migration
    state = migration.apply(state, schema_editor)
  File "C:\Python27\lib\site-packages\django\db\migrations\migration.py", line 123, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "C:\Python27\lib\site-packages\django\db\migrations\operations\fields.py", line 121, in database_forwards
    schema_editor.remove_field(from_model, from_model._meta.get_field(self.name))
  File "C:\Python27\lib\site-packages\django\db\backends\sqlite3\schema.py", line 247, in remove_field
    self._remake_table(model, delete_fields=[field])
  File "C:\Python27\lib\site-packages\django\db\backends\sqlite3\schema.py", line 197, in _remake_table
    self.quote_name(model._meta.db_table),
  File "C:\Python27\lib\site-packages\django\db\backends\base\schema.py", line 110, in execute
    cursor.execute(sql, params)
  File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "C:\Python27\lib\site-packages\django\db\utils.py", line 95, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "C:\Python27\lib\site-packages\django\db\backends\sqlite3\base.py", line 323, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: near ")": syntax error

Here's the contents of 0006_auto_20160621_1640.py

# -*- coding: utf-8 -*-

# Generated by Django 1.9.6 on 2016-06-21 22:40
from __future__ import unicode_literals

from django.db import migrations


class Migration(migrations.Migration):

    dependencies = [
        ('optilab', '0005_test'),
    ]

    operations = [
        migrations.RemoveField(
            model_name='lasersubstrate',
            name='substrate_ptr',
        ),
        migrations.RemoveField(
            model_name='waveguidesubstrate',
            name='substrate_ptr',
        ),
        migrations.DeleteModel(
            name='LaserSubstrate',
        ),
        migrations.DeleteModel(
            name='WaveguideSubstrate',
        ),
    ]

Here's the SQL produced from running 'python manage.py sqlmigrate optilab 0006'

BEGIN;
--
-- Remove field substrate_ptr from lasersubstrate
--
ALTER TABLE "optilab_lasersubstrate" RENAME TO "optilab_lasersubstrate__old";
CREATE TABLE "optilab_lasersubstrate" ("substrate_ptr_id" integer NOT NULL PRIMARY KEY REFERENCES "optilab_substrate" ("id"));
INSERT INTO "optilab_lasersubstrate" () SELECT  FROM "optilab_lasersubstrate__old";
DROP TABLE "optilab_lasersubstrate__old";
--
-- Remove field substrate_ptr from waveguidesubstrate
--
ALTER TABLE "optilab_waveguidesubstrate" RENAME TO "optilab_waveguidesubstrate__old";
CREATE TABLE "optilab_waveguidesubstrate" ("substrate_ptr_id" integer NOT NULL PRIMARY KEY REFERENCES "optilab_substrate" ("id"));
INSERT INTO "optilab_waveguidesubstrate" () SELECT  FROM "optilab_waveguidesubstrate__old";
DROP TABLE "optilab_waveguidesubstrate__old";
--
-- Delete model LaserSubstrate
--
DROP TABLE "optilab_lasersubstrate";
--
-- Delete model WaveguideSubstrate
--
DROP TABLE "optilab_waveguidesubstrate";

COMMIT;

Answer 1

This appears to be the line that's causing the errror:

 INSERT INTO "optilab_lasersubstrate" () SELECT  FROM "optilab_lasersubstrate__old";

You are usually expected to have a list of columns in those parenthesis. Eg INSERT INTO "optilab_lasersubstrate" (col1,col2,etc) however the migration has produced a blank set! Similarly the SELECT FROM portion should read as SELECT col1,col2 FROM . By some strange set of events you appear to have managed to create a table with no columns!!

I see from your migration file that you are anyway dropping this table. So there isn't any reason to struggle with the RemoveField portion. It's code associated with the RemoveField that's causing the error. Change your migration as follows:

class Migration(migrations.Migration):

    dependencies = [
        ('optilab', '0005_test'),
    ]

    operations = [
        migrations.DeleteModel(
            name='LaserSubstrate',
        ),
        migrations.DeleteModel(
            name='WaveguideSubstrate',
        ),
    ]

Answer 2

Edit base.py in the lines that breaks and update it to:

def execute(self, query, params=None):
    if params is None:
        if '()' not in str(query):
            return Database.Cursor.execute(self, query)
    query = self.convert_query(query)
    if '()' not in str(query):
        return Database.Cursor.execute(self, query, params)