Coalescence of global and local metadata with effective date
Original Publication Date: 2001-Aug-01
Included in the Prior Art Database: 2003-Jun-20
Disclosed is a mechanism for overriding a base set of data (global or default values) with local data when appropriate, and for using an "effective date" value to decide which data is applicable. It is often necessary in applications to provide a way to override default values with specific local values. An example is overriding federal laws when locally applicable state or municipal laws provide exceptions. These types of rules often have an effective date as new legislation becomes law. From a programmer's point of view all of this detail should be hidden. Given a request for a piece of data and criteria such as a state or municipality name, the retrieval algorithm should resolve (or "coalesce") the effective date and criteria and return the appropriate data. The disclosed mechanism includes a method for organizing data, and a lookup algorithm. Each row of data contains attributes for a major criterion. In the example above this would be the state. As legislation changes, additional rows are added with the appropriate effective date. The lookup for the row representing rules in effect for a particular locality at a particular time is straightforward.