125 lines
4.9 KiB
Python
125 lines
4.9 KiB
Python
from .base import Operation
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class AddField(Operation):
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"""
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Adds a field to a model.
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"""
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def __init__(self, model_name, name, field):
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self.model_name = model_name
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self.name = name
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self.field = field
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def state_forwards(self, app_label, state):
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state.models[app_label, self.model_name.lower()].fields.append((self.name, self.field))
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def database_forwards(self, app_label, schema_editor, from_state, to_state):
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from_model = from_state.render().get_model(app_label, self.model_name)
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to_model = to_state.render().get_model(app_label, self.model_name)
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schema_editor.add_field(from_model, to_model._meta.get_field_by_name(self.name)[0])
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def database_backwards(self, app_label, schema_editor, from_state, to_state):
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from_model = from_state.render().get_model(app_label, self.model_name)
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schema_editor.remove_field(from_model, from_model._meta.get_field_by_name(self.name)[0])
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def describe(self):
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return "Add field %s to %s" % (self.name, self.model_name)
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class RemoveField(Operation):
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"""
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Removes a field from a model.
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"""
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def __init__(self, model_name, name):
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self.model_name = model_name
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self.name = name
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def state_forwards(self, app_label, state):
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new_fields = []
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for name, instance in state.models[app_label, self.model_name.lower()].fields:
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if name != self.name:
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new_fields.append((name, instance))
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state.models[app_label, self.model_name.lower()].fields = new_fields
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def database_forwards(self, app_label, schema_editor, from_state, to_state):
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from_model = from_state.render().get_model(app_label, self.model_name)
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schema_editor.remove_field(from_model, from_model._meta.get_field_by_name(self.name)[0])
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def database_backwards(self, app_label, schema_editor, from_state, to_state):
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from_model = from_state.render().get_model(app_label, self.model_name)
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to_model = to_state.render().get_model(app_label, self.model_name)
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schema_editor.add_field(from_model, to_model._meta.get_field_by_name(self.name)[0])
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def describe(self):
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return "Remove field %s from %s" % (self.name, self.model_name)
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class AlterField(Operation):
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"""
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Alters a field's database column (e.g. null, max_length) to the provided new field
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"""
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def __init__(self, model_name, name, field):
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self.model_name = model_name
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self.name = name
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self.field = field
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def state_forwards(self, app_label, state):
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state.models[app_label, self.model_name.lower()].fields = [
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(n, self.field if n == self.name else f) for n, f in state.models[app_label, self.model_name.lower()].fields
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]
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def database_forwards(self, app_label, schema_editor, from_state, to_state):
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from_model = from_state.render().get_model(app_label, self.model_name)
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to_model = to_state.render().get_model(app_label, self.model_name)
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schema_editor.alter_field(
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from_model,
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from_model._meta.get_field_by_name(self.name)[0],
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to_model._meta.get_field_by_name(self.name)[0],
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)
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def database_backwards(self, app_label, schema_editor, from_state, to_state):
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self.database_forwards(app_label, schema_editor, from_state, to_state)
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def describe(self):
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return "Alter field %s on %s" % (self.name, self.model_name)
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class RenameField(Operation):
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"""
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Renames a field on the model. Might affect db_column too.
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"""
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def __init__(self, model_name, old_name, new_name):
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self.model_name = model_name
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self.old_name = old_name
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self.new_name = new_name
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def state_forwards(self, app_label, state):
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state.models[app_label, self.model_name.lower()].fields = [
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(self.new_name if n == self.old_name else n, f) for n, f in state.models[app_label, self.model_name.lower()].fields
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]
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def database_forwards(self, app_label, schema_editor, from_state, to_state):
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from_model = from_state.render().get_model(app_label, self.model_name)
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to_model = to_state.render().get_model(app_label, self.model_name)
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schema_editor.alter_field(
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from_model,
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from_model._meta.get_field_by_name(self.old_name)[0],
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to_model._meta.get_field_by_name(self.new_name)[0],
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)
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def database_backwards(self, app_label, schema_editor, from_state, to_state):
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from_model = from_state.render().get_model(app_label, self.model_name)
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to_model = to_state.render().get_model(app_label, self.model_name)
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schema_editor.alter_field(
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from_model,
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from_model._meta.get_field_by_name(self.new_name)[0],
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to_model._meta.get_field_by_name(self.old_name)[0],
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)
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def describe(self):
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return "Rename field %s on %s to %s" % (self.old_name, self.model_name, self.new_name)
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