Merge pull request #335 from alphagov/fix-history-data

Data migration script to fix templates_history.updated_at.

migrations/versions/0020_template_history_fix.py

@@ -0,0 +1,23 @@
+"""empty message
+
+Revision ID: 0020_template_history_fix
+Revises: 0019_add_job_row_number
+Create Date: 2016-05-20 15:15:03.850862
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '0020_template_history_fix'
+down_revision = '0019_add_job_row_number'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+   op.get_bind()
+   op.execute('update templates_history t set updated_at = (select updated_at from templates_history th where t.version = th.version -1 and t.id = th.id  and t.version != 1)')
+   op.execute('update templates_history th set updated_at = (select t.updated_at from templates_history h, templates t where h.id = t.id and h.version = t.version and th.id = h.id) where (th.id, th.version) = (select t.id, t.version from templates t where t.id = th.id and t.version = th.version)')
+
+def downgrade():
+    pass