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select_action

SelectAction

Bases: QueryAction

Order Actions is populated by queryset when order_by() is called.

All required params are extracted but kept raw until actual filter clause value is required -> then the action is converted into text() clause.

Extracted in order to easily change table prefixes on complex relations.

Source code in ormar/queryset/actions/select_action.py
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class SelectAction(QueryAction):
    """
    Order Actions is populated by queryset when order_by() is called.

    All required params are extracted but kept raw until actual filter clause value
    is required -> then the action is converted into text() clause.

    Extracted in order to easily change table prefixes on complex relations.
    """

    def __init__(
        self, select_str: str, model_cls: Type["Model"], alias: str = None
    ) -> None:
        super().__init__(query_str=select_str, model_cls=model_cls)
        if alias:  # pragma: no cover
            self.table_prefix = alias

    def _split_value_into_parts(self, order_str: str) -> None:
        parts = order_str.split("__")
        self.field_name = parts[-1]
        self.related_parts = parts[:-1]

    @property
    def is_numeric(self) -> bool:
        return self.get_target_field_type() in [int, float, decimal.Decimal]

    def get_target_field_type(self) -> Any:
        return self.target_model.Meta.model_fields[self.field_name].__type__

    def get_text_clause(self) -> sqlalchemy.sql.expression.TextClause:
        alias = f"{self.table_prefix}_" if self.table_prefix else ""
        return sqlalchemy.text(f"{alias}{self.field_name}")

    def apply_func(
        self, func: Callable, use_label: bool = True
    ) -> sqlalchemy.sql.expression.TextClause:
        result = func(self.get_text_clause())
        if use_label:
            rel_prefix = f"{self.related_str}__" if self.related_str else ""
            result = result.label(f"{rel_prefix}{self.field_name}")
        return result