Workday stores your data as business objects—organizations, workers, positions, and so on—which can be thought of as database tables or worksheets in Excel. Just as a database table or worksheet has columns and rows, a Workday business object has fields and instances. A business object is composed of a set of related fields, similar to how a table or spreadsheet is composed of a set of related columns. Instances of a business object in Workday are like rows in a table or spreadsheet, with each instance representing a unique occurrence of that type of object such as an organization or worker. A business object can have no instances, one instance, or many instances. Workday automatically links related business objects together. For example, purchase order lines are linked to a purchase order header, the purchase order header is linked to a supplier, the supplier is linked to a company, and so on.