 Data items in COBOL are declared hierarchically through the use of level-numbers which indicate if a data item is part of another. An item with a higher level-number is subordinate to an item with a lower one. Top-level data items, with a level-number of 1, are called records. Items that have subordinate aggregate data are called group items; those that do not are called elementary items. Level-numbers used to describe standard data items are between 1 and 49.
