Code layout change.

[wolnelektury.git] / src / catalogue / migrations / 0003_populate_ancestors.py

diff --git a/src/catalogue/migrations/0003_populate_ancestors.py b/src/catalogue/migrations/0003_populate_ancestors.py
new file mode 100644 (file)
index 0000000..b611757
--- /dev/null
+++ b/src/catalogue/migrations/0003_populate_ancestors.py
@@ -0,0 +1,54 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+def populate_ancestors(apps, schema_editor):
+    """Fixes the ancestry cache."""
+    # TODO: table names
+    from django.db import connection, transaction
+    if connection.vendor == 'postgres':
+        cursor = connection.cursor()
+        cursor.execute("""
+            WITH RECURSIVE ancestry AS (
+                SELECT book.id, book.parent_id
+                FROM catalogue_book AS book
+                WHERE book.parent_id IS NOT NULL
+                UNION
+                SELECT ancestor.id, book.parent_id
+                FROM ancestry AS ancestor, catalogue_book AS book
+                WHERE ancestor.parent_id = book.id
+                    AND book.parent_id IS NOT NULL
+                )
+            INSERT INTO catalogue_book_ancestor
+                (from_book_id, to_book_id)
+                SELECT id, parent_id
+                FROM ancestry
+                ORDER BY id;
+            """)
+    else:
+        Book = apps.get_model("catalogue", "Book")
+        for book in Book.objects.exclude(parent=None):
+            parent = book.parent
+            while parent is not None:
+                book.ancestor.add(parent)
+                parent = parent.parent
+
+
+def remove_book_tags(apps, schema_editor):
+    Tag = apps.get_model("catalogue", "Tag")
+    Book = apps.get_model("catalogue", "Book")
+    Tag.objects.filter(category='book').delete()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('catalogue', '0002_book_ancestor'),
+    ]
+
+    operations = [
+        migrations.RunPython(populate_ancestors),
+        migrations.RunPython(remove_book_tags),
+    ]