Class Function

tortoise/expressions.py:514–599

Function/Aggregate base. :param field: Field name :param default_values: Extra parameters to the function. .. attribute:: database_func :annotation: pypika_tortoise.terms.Function The pypika function this represents. .. attribute:: populate_field_object

class Function(Expression):
    """
    Function/Aggregate base.

    :param field: Field name
    :param default_values: Extra parameters to the function.

    .. attribute:: database_func
        :annotation: pypika_tortoise.terms.Function

        The pypika function this represents.

    .. attribute:: populate_field_object
        :annotation: bool = False

        Enable populate_field_object where we want to try and preserve the field type.
    """

    __slots__ = ("field", "field_object", "default_values")

    database_func: type[PypikaFunction] = PypikaFunction
    # Enable populate_field_object where we want to try and preserve the field type.
    populate_field_object = False

    def __init__(
        self, field: str | F | CombinedExpression | Function | Term, *default_values: Any
    ) -> None:
        self.field = field
        self.field_object: Field | None = None
        self.default_values = default_values

    def _get_function_field(self, field: Term | str, *default_values) -> PypikaFunction:
        return self.database_func(field, *default_values)  # type:ignore[arg-type]

    def _resolve_nested_field(self, resolve_context: ResolveContext, field: str) -> ResolveResult:
        term, joins, output_field = resolve_nested_field(
            resolve_context.model, resolve_context.table, field
        )
        if self.populate_field_object:
            self.field_object = output_field
        return ResolveResult(term=term, joins=joins, output_field=output_field)

    def _resolve_argument(
        self, resolve_context: ResolveContext, value: Any, *, treat_str_as_field: bool
    ) -> ResolveResult:
        if isinstance(value, Expression):
            return value.resolve(resolve_context)
        if isinstance(value, Term):
            return ResolveResult(term=value)
        if isinstance(value, str) and treat_str_as_field:
            return self._resolve_nested_field(resolve_context, value)
        return ResolveResult(term=value)

    def resolve(self, resolve_context: ResolveContext) -> ResolveResult:
        """
        Used to resolve the Function statement for SQL generation.

        :param model: Model the function is applied on to.