python类extra()的实例源码

def __repr__(self):
        args = self.arg_joiner.join(str(arg) for arg in self.source_expressions)
        extra = ', '.join(str(key) + '=' + str(val) for key, val in self.extra.items())
        if extra:
            return "{}({}, {})".format(self.__class__.__name__, args, extra)
        return "{}({})".format(self.__class__.__name__, args)

def copy(self):
        copy = super(Func, self).copy()
        copy.source_expressions = self.source_expressions[:]
        copy.extra = self.extra.copy()
        return copy

def __init__(self, *cases, **extra):
        if not all(isinstance(case, When) for case in cases):
            raise TypeError("Positional arguments must all be When objects.")
        default = extra.pop('default', None)
        output_field = extra.pop('output_field', None)
        super(Case, self).__init__(output_field)
        self.cases = list(cases)
        self.default = self._parse_expressions(default)[0]
        self.extra = extra

def __init__(self, queryset, output_field=None, **extra):
        self.queryset = queryset
        self.extra = extra
        if output_field is None and len(self.queryset.query.select) == 1:
            output_field = self.queryset.query.select[0].field
        super(Subquery, self).__init__(output_field)

def as_sql(self, compiler, connection, template=None, **extra_context):
        connection.ops.check_expression_support(self)
        template_params = self.extra.copy()
        template_params.update(extra_context)
        template_params['subquery'], sql_params = self.queryset.query.get_compiler(connection=connection).as_sql()

        template = template or template_params.get('template', self.template)
        sql = template % template_params
        return sql, sql_params

def __invert__(self):
        return type(self)(self.queryset, self.output_field, negated=(not self.negated), **self.extra)

def __init__(self, *expressions, **extra):
        output_field = extra.pop('output_field', None)
        super(Func, self).__init__(output_field=output_field)
        self.source_expressions = self._parse_expressions(*expressions)
        self.extra = extra

def __repr__(self):
        args = self.arg_joiner.join(str(arg) for arg in self.source_expressions)
        extra = ', '.join(str(key) + '=' + str(val) for key, val in self.extra.items())
        if extra:
            return "{}({}, {})".format(self.__class__.__name__, args, extra)
        return "{}({})".format(self.__class__.__name__, args)

def as_sql(self, compiler, connection, function=None, template=None):
        connection.ops.check_expression_support(self)
        sql_parts = []
        params = []
        for arg in self.source_expressions:
            arg_sql, arg_params = compiler.compile(arg)
            sql_parts.append(arg_sql)
            params.extend(arg_params)
        if function is None:
            self.extra['function'] = self.extra.get('function', self.function)
        else:
            self.extra['function'] = function
        self.extra['expressions'] = self.extra['field'] = self.arg_joiner.join(sql_parts)
        template = template or self.extra.get('template', self.template)
        return template % self.extra, params

def copy(self):
        copy = super(Func, self).copy()
        copy.source_expressions = self.source_expressions[:]
        copy.extra = self.extra.copy()
        return copy

def __init__(self, *cases, **extra):
        if not all(isinstance(case, When) for case in cases):
            raise TypeError("Positional arguments must all be When objects.")
        default = extra.pop('default', None)
        output_field = extra.pop('output_field', None)
        super(Case, self).__init__(output_field)
        self.cases = list(cases)
        self.default = self._parse_expressions(default)[0]