Function join_condition

lib/sqlalchemy/sql/util.py:95–128

Create a join condition between two tables or selectables. e.g.:: join_condition(tablea, tableb) would produce an expression along the lines of:: tablea.c.id == tableb.c.tablea_id The join is determined based on the foreign key relationships between the two selec

(
    a: FromClause,
    b: FromClause,
    a_subset: Optional[FromClause] = None,
    consider_as_foreign_keys: Optional[AbstractSet[ColumnClause[Any]]] = None,
)

def join_condition(
    a: FromClause,
    b: FromClause,
    a_subset: Optional[FromClause] = None,
    consider_as_foreign_keys: Optional[AbstractSet[ColumnClause[Any]]] = None,
) -> ColumnElement[bool]:
    """Create a join condition between two tables or selectables.

    e.g.::

        join_condition(tablea, tableb)

    would produce an expression along the lines of::

        tablea.c.id == tableb.c.tablea_id

    The join is determined based on the foreign key relationships
    between the two selectables.   If there are multiple ways
    to join, or no way to join, an error is raised.

    :param a_subset: An optional expression that is a sub-component
        of ``a``.  An attempt will be made to join to just this sub-component
        first before looking at the full ``a`` construct, and if found
        will be successful even if there are other ways to join to ``a``.
        This allows the "right side" of a join to be passed thereby
        providing a "natural join".

    """
    return Join._join_condition(
        a,
        b,
        a_subset=a_subset,
        consider_as_foreign_keys=consider_as_foreign_keys,
    )


def find_join_source(