DROP FUNCTION IF EXISTS mocha_get_instance_by_key;

CREATE FUNCTION mocha_get_instance_by_key
(
    p_class_id INT,
    p_inst_id INT
)
RETURNS INT
RETURN (SELECT id FROM mocha_instances
    
    WHERE (tenant_id = mocha_get_current_tenant()
    OR tenant_id IN (SELECT target_tenant_id FROM mocha_tenant_references WHERE source_tenant_id = mocha_get_current_tenant())
    )
    AND class_id = p_class_id
    AND inst_id = p_inst_id
    LIMIT 1
);