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Improved Object Location in Hierarchical Database

IP.com Disclosure Number: IPCOM000118853D
Original Publication Date: 1997-Aug-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 1 page(s) / 37K

Publishing Venue

IBM

Related People

Harrison, R: AUTHOR [+2]

Abstract

In a hierarchical database, objects may be located by a cursor which can be navigated. If a cursor is located on an object, it can query the attributes of that object. It may be desirable to query the attributes of objects higher in the hierarchy, but this entails navigating the cursor up the tree to the object which has the desired attribute and returning to the object the cursor was on originally. This is a costly exercise, and it is not necessarily known which object in the tree has the attribute.

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Improved Object Location in Hierarchical Database

      In a hierarchical database, objects may be located by a cursor
which can be navigated.  If a cursor is located on an object, it can
query the attributes of that object.  It may be desirable to query
the attributes of objects higher in the hierarchy, but this entails
navigating the cursor up the tree to the object which has the desired
attribute and returning to the object the cursor was on originally.
This is a costly exercise, and it is not necessarily known which
object in the  tree has the attribute.

      This problem may be solved by attribute delegation.  The
implementation of the attribute query function must know that the
attribute requested may not be on the current object but might
instead be located on one of the object's chain of parents.  The
implementation will scan up the tree until it finds the attribute
requested and then report this as if it were an attribute of the
object currently located  by the cursor.

      This is a form of inheritance applied to a hierarchical
database.  For example, a database which stores personnel in a
hierarchy: country/location/department/person.  The person object has
a salary attribute, the department has a project box, the location
has a  postal address.

      With the scheme proposed, it is possible to query the person
object for his salary, his departmental project box, and his
location's postal address directly.

      A refinement is...