1)

def get_or_create(table, required_fields={}, updated_fields={}):
    """
    Return record from table with passed field values. Create record if does not exist.

    'table' is a DAL table reference, such as 'db.person'
    'required_fields' is a dict, such as {'parent': 4, name: 'Richard'}
    """
    if required_fields:
        logic = reduce(lambda a, b : a & b, [table[k] == required_fields[k] for k in required_fields])
    else:
        logic = table.id > 0 # select any record if no fields passed
    record = db(logic).select().first()
    if record:
        if updated_fields:
            record.update_record(updated_fields)
        return record
    else:
        updated_fields.update(required_fields)
        return table.insert(**updated_fields)

2)

def update_or_create(table, required_fields, updated_fields):
    """
    Modify record from table that matches 'required_fields' with 'updated_fields'.
    If record with 'required_fields' does not exist then create it.

    'table' is a DAL table reference, such as 'db.person'
    'required_fields' and 'updated_fields' are dicts, such as {'parent': 4, name: 'Richard'}
    """
    logic = reduce(lambda a, b : a & b, [table[k] == required_fields[k] for k in required_fields]) 
    record = db(logic).select().first()
    if record is None:
        record = table.insert(**required_fields)
    record.update_record(**updated_fields)