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80 lines
2.6 KiB
Python
80 lines
2.6 KiB
Python
"""Adds and removes category relations on the database."""
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from django.apps import apps
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from django.db import DatabaseError, connection, transaction
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from django.db.utils import OperationalError, ProgrammingError
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def table_exists(table_name):
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"""
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Check if a table exists in the database.
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"""
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pass
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def field_exists(app_name, model_name, field_name):
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"""
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Does the FK or M2M table exist in the database already?
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"""
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model = apps.get_model(app_name, model_name)
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table_name = model._meta.db_table
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cursor = connection.cursor()
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field_info = connection.introspection.get_table_description(cursor, table_name)
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field_names = [f.name for f in field_info]
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# Return True if the many to many table exists
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field = model._meta.get_field(field_name)
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if hasattr(field, "m2m_db_table"):
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m2m_table_name = field.m2m_db_table()
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try:
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m2m_field_info = connection.introspection.get_table_description(cursor, m2m_table_name)
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except DatabaseError: # Django >= 4.1 throws DatabaseError
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m2m_field_info = []
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if m2m_field_info:
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return True
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return field_name in field_names
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def drop_field(app_name, model_name, field_name):
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"""
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Drop the given field from the app's model.
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"""
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app_config = apps.get_app_config(app_name)
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model = app_config.get_model(model_name)
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field = model._meta.get_field(field_name)
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with connection.schema_editor() as schema_editor:
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schema_editor.remove_field(model, field)
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def migrate_app(sender, *args, **kwargs):
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"""
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Migrate all models of this app registered.
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"""
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from .registration import registry
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if "app_config" not in kwargs:
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return
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app_config = kwargs["app_config"]
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app_name = app_config.label
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fields = [fld for fld in list(registry._field_registry.keys()) if fld.startswith(app_name)]
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sid = transaction.savepoint()
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for fld in fields:
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model_name, field_name = fld.split(".")[1:]
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if field_exists(app_name, model_name, field_name):
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continue
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model = app_config.get_model(model_name)
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try:
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with connection.schema_editor() as schema_editor:
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schema_editor.add_field(model, registry._field_registry[fld])
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if sid:
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transaction.savepoint_commit(sid)
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# Django 4.1 with sqlite3 has for some reason started throwing OperationalError
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# instead of ProgrammingError, so we need to catch both.
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except (ProgrammingError, OperationalError):
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if sid:
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transaction.savepoint_rollback(sid)
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continue
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