53 lines
1.9 KiB
Python
53 lines
1.9 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, instance):
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self.model_name = model_name
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self.name = name
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self.instance = instance
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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.instance))
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def database_forwards(self, app_label, schema_editor, from_state, to_state):
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app_cache = to_state.render()
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model = app_cache.get_model(app_label, self.model_name)
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schema_editor.add_field(model, 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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app_cache = from_state.render()
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model = app_cache.get_model(app_label, self.model_name)
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schema_editor.remove_field(model, model._meta.get_field_by_name(self.name)[0])
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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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app_cache = from_state.render()
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model = app_cache.get_model(app_label, self.model_name)
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schema_editor.remove_field(model, 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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app_cache = to_state.render()
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model = app_cache.get_model(app_label, self.model_name)
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schema_editor.add_field(model, model._meta.get_field_by_name(self.name)[0])
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