System for updating local views from a global database using time stamps to determine when a change has occurred

• US 5,388,255 A
• Filed: 12/19/1991
• Issued: 02/07/1995
• Est. Priority Date: 12/19/1991
• Status: Expired due to Term

• Current Assignee: AD Technologies LLC
• Original Assignee: Wang Laboratories Incorporated
• Inventors: LaValle, Arthur R., Pytlik, Bogdan, O'Hara, Abigail L.
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): Choules, Jack M.
• Application Number:
  US07/810,245
• Time in Patent Office: 1,146 Days
• Field of Search: 395/600
• US Class Current: 1/1
• CPC Class Codes: G06F 16/217 Database tuning G06F16/2282 takes precedence; database performance monitoring G06F11/3409
• CPC Class Codes: G06F 16/24539 using cached or materialised query results
• CPC Class Codes: Y10S 707/99934 Query formulation, input preparation, or translation
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

An Open Office Directory System stores information in the form of entries in a global database and views in a local database along with a time stamp indicating the date the view was originally written or last modified. Subsets of the selected global entries are stored as views in a local database with the time stamp of the last generation or modification of that view in the global database. The entries in the global database are queried periodically by the local site to compare the time stamps of the local views with the respective entries in the global database. The result of a non-comparison is to update the local view including its time stamp to agree with the global database entry(s).

Claims

1. A method of formulating a search for changed entries in a global database and updating local views including the steps of

at selected time frame intervals,

A. building a list of all installed local view names;

B. developing a list of desired attributes for display in each local view identified in the list of installed local view names, the attributes for each local view including a latest time stamp value for the local view wherein each latest time stamp value indicates the time of a last change to the local view and definitions of the local view;

C. selecting a local view name from the list of installed local view names;

D. reading from the attribute list for the selected local view name the view definitions and the latest time stamp value for the selected local view name;

E. searching the global database using said view definitions to locate an entry corresponding to the selected local view name;

F. when the entry corresponding to the selected local view name is a non-leaf entry, selecting a next entry;

G. when the entry corresponding to the selected local view name is a leaf entry, comparing the time stamp value of the entry with the latest time stamp value for the selected view name from the list of attributes corresponding to the selected local view name;

H. updating the local view corresponding to the selected local view name when the time stamp value of the entry is different from the latest time stamp value for the selected view name;

I. determining when all entries corresponding to the selected local view name are processed;

J. selecting a next entry corresponding to the selected local view name when all entries corresponding to the selected local view name are not processed;

K. selecting a next local view name when all entries corresponding to the selected local view name are processed; and

L. repeating steps C through K until all local view names in the list of all installed local view names are processed.

2. An Open Office Directory System for building and updating views stored in a local subdirectory comprises:

global database means for storing a global distributed directory;

a builder means for controlling when an application that builds and updates said views is to be executed;

a view management means for periodically scanning the global database for the views stored in the local subdirectory for changes in the views stored in the local subdirectory and for storing a latest time stamp value in attributes associated with each view in the local subdirectory wherein each latest time stamp value represents a time at which the associated view stored in the local subdirectory was last changed;

an update means coupled to said builder means for working cooperatively with the view management means to determine a change in said gloabal data base for a view stored in the local subdirectory in a current update scan by storing a time frame of a last update scan in said update means wherein the view management means is responsive to the stored time frame of the last update scan for comparing the latest time stamp values of the views stored in the gloabal database for the views stored in the local subdirectory with the stored time frame of the last update scan and determining when a change in a view stored in the local subdirectory occurred subsequent to the last update scan;

a definition means coupled to said update means and to global database means for providing selection criteria and predicates from the attributes associated with views stored in the local subdirectory for each view stored for which a change is determined in said current update scan to have occurred subsequent to the last update scan for reading the selected attributes from entries stored in said global database means for which a change has occurred subsequent to the last update scan; and

an entry means coupled to said global database means for storing the local entries which are received from said global database means in the local subdirectory, thereby updating the views stored in the local subdirectory.