Class Func

django/db/models/expressions.py:1054–1144

An SQL function call.

@deconstructible(path="django.db.models.Func")
class Func(SQLiteNumericMixin, Expression):
    """An SQL function call."""

    function = None
    template = "%(function)s(%(expressions)s)"
    arg_joiner = ", "
    arity = None  # The number of arguments the function accepts.

    def __init__(self, *expressions, output_field=None, **extra):
        if self.arity is not None and len(expressions) != self.arity:
            raise TypeError(
                "'%s' takes exactly %s %s (%s given)"
                % (
                    self.__class__.__name__,
                    self.arity,
                    "argument" if self.arity == 1 else "arguments",
                    len(expressions),
                )
            )
        super().__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 = {**self.extra, **self._get_repr_options()}
        if extra:
            extra = ", ".join(
                str(key) + "=" + str(val) for key, val in sorted(extra.items())
            )
            return "{}({}, {})".format(self.__class__.__name__, args, extra)
        return "{}({})".format(self.__class__.__name__, args)

    def _get_repr_options(self):
        """Return a dict of extra __init__() options to include in the repr."""
        return {}

    def get_source_expressions(self):
        return self.source_expressions

    def set_source_expressions(self, exprs):
        self.source_expressions = exprs

    def as_sql(
        self,
        compiler,
        connection,
        function=None,
        template=None,
        arg_joiner=None,
        **extra_context,
    ):
        connection.ops.check_expression_support(self)
        sql_parts = []
        params = []
        for arg in self.source_expressions:
            try:
                arg_sql, arg_params = compiler.compile(arg)