55 lines
1.9 KiB
Python
55 lines
1.9 KiB
Python
from django.db.models.sql.query import Query
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__all__ = ['CheckConstraint']
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class CheckConstraint:
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def __init__(self, constraint, name):
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self.constraint = constraint
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self.name = name
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def constraint_sql(self, model, schema_editor):
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query = Query(model)
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where = query.build_where(self.constraint)
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connection = schema_editor.connection
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compiler = connection.ops.compiler('SQLCompiler')(query, connection, 'default')
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sql, params = where.as_sql(compiler, connection)
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params = tuple(schema_editor.quote_value(p) for p in params)
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return schema_editor.sql_check % {
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'name': schema_editor.quote_name(self.name),
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'check': sql % params,
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}
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def create_sql(self, model, schema_editor):
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sql = self.constraint_sql(model, schema_editor)
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return schema_editor.sql_create_check % {
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'table': schema_editor.quote_name(model._meta.db_table),
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'check': sql,
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}
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def remove_sql(self, model, schema_editor):
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quote_name = schema_editor.quote_name
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return schema_editor.sql_delete_check % {
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'table': quote_name(model._meta.db_table),
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'name': quote_name(self.name),
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}
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def __repr__(self):
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return "<%s: constraint='%s' name='%s'>" % (self.__class__.__name__, self.constraint, self.name)
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def __eq__(self, other):
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return (
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isinstance(other, CheckConstraint) and
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self.name == other.name and
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self.constraint == other.constraint
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)
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def deconstruct(self):
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path = '%s.%s' % (self.__class__.__module__, self.__class__.__name__)
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path = path.replace('django.db.models.constraints', 'django.db.models')
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return (path, (), {'constraint': self.constraint, 'name': self.name})
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def clone(self):
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_, args, kwargs = self.deconstruct()
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return self.__class__(*args, **kwargs)
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