Data processing: database and file management or data structures – Database design – Data structure types
Reexamination Certificate
1997-11-05
2001-12-11
Black, Thomas (Department: 2171)
Data processing: database and file management or data structures
Database design
Data structure types
C707S793000, C707S793000, C707S793000
Reexamination Certificate
active
06330568
ABSTRACT:
BACKGROUND
This invention relates to synchronizing incompatible databases.
Databases are collections of data entries which are organized, stored, and manipulated in a manner specified by applications known as database managers (hereinafter also referred to as “Applications”; hereinafter, the term “database” also refers to a database manager combined with a database proper). The manner in which database entries are organized in a database is known as the data structure of a database. There are generally two types of database managers. First are general purpose database managers in which the user determines (usually at the outset, but subject to future revisions) what the data structure is. These Applications often have their own programming language and provide great flexibility to the user. Second are special purpose database managers that are specifically designed to create and manage a database having a preset data structure. Examples of these special purpose database managers are various scheduling, diary, and contact manager Applications for desktop and handheld computers. Database managers organize the information in a database into records, with each record made up of fields. Fields and records of a database may have many different characteristics depending on the database manager's purpose and utility.
Databases can be said to be incompatible with one another when the data structure of one is not the same as the data structure of another, even though some of the content of the records is substantially the same. For example, one database may store names and addresses in the following fields: FIRST_NAME, LAST_NAME, and ADDRESS. Another database may, however, store the same information with the following structure: NAME, STREET_NO., STREET_NAME, CITY_STATE, and ZIP. Although the content of the records is intended to contain the same kind of information, the organization of that information is completely different.
Often users of incompatible databases want to be able to synchronize them with one another. For example, in the context of scheduling and contact manager Applications, a person might use one Application on the desktop computer at work while another on his handheld computer or his laptop computer while away from work. It is desirable for many of these users to be able to synchronize the entries on one with entries on another. The U.S. patent and copending patent application of the assignee hereof, Puma Technology, Inc. of St. Jose, Calif. (U.S. Pat. No. 5,392,390 (hereinafter, “the '390 patent”); U.S. application, Ser. No. 08/371,194, filed on Jan. 11, 1995, incorporated by reference herein) show two methods for synchronizing incompatible databases and solving some of the problems arising from incompatibility of databases.
Synchronization of two incompatible databases often requires comparison of their records so that they can be matched up prior to synchronization. This may require transferring records in one database from one computer to another. However, if the data transfer link between the two computers is slow, as for example is the case with current infrared ports, telephone modem, or small handheld computers, such a transfer increases the required time for synchronization by many folds.
SUMMARY
The invention provides for using certain design characteristics of certain Applications to speed up the synchronization process. Some Applications provide information for keeping track of which records were changed, deleted, or added since the last synchronization. The invention uses these features to speed up the synchronization process by retrieving only those records which have been changed or added since a previous synchronization.
In one general aspect, the invention provides a computer implemented method and a computer program for synchronizing a first and a second database. Based on data reflecting whether the records of the first database have been added or changed since a previous synchronization, it is determined whether the records of the first database have been changed or added since the previous synchronization. If one of the records of the first database has not been changed or added since the previous synchronization, a synchronization with records of the second database is performed using a record representative of the one record at the time of a previous synchronization. The representative record is stored in a history file which contains records reflecting the contents of records of the databases at the time of a previous synchronization.
Preferred embodiments may include one or more of the following features.
The data provided for keeping track of whether the records of the first database have been added or changed since a previous synchronization may be database generated data, stored in the records of the first database.
The computer generated data indicates the most recent date and time of when a record was created or changed. The computer generated data includes a flag set when a record is created or changed.
The first database provides further database generated data indicating which records were deleted since the previous synchronization. Records of the history file corresponding to the deleted records are identified by performing a comparison of the further computer generated data with the history file. Records of the history file corresponding to records of the first database deleted since the previous synchronization are identified by performing a comparison of the records of the history file and a result of determining which of the records of the first database have been added or deleted.
The first database assigns a unique identification data to the records of the first database. A comparison of the records of the history file is made to the unique identification data of records in the first database that have been changed or added since the previous synchronization. The synchronization is completed using a result of the comparison.
Records of the first database and the history file are modified, added, or deleted based on the results of the synchronization. The history file contains records reflecting the contents of records of the databases at the time of the current synchronization.
Embodiments of the invention may include one or more of the following advantages.
Some embodiments of the invention reduce the number of unchanged records that need to be read from the databases in order to synchronize the databases with one another. Typically a majority of the database records are unchanged. Therefore, not reading the unchanged record reduces the time required to synchronize the databases, especially where the data transfer link between the two computers which store the databases is slow.
The invention may be implemented in hardware or software, or a combination of both. Preferably, the technique is implemented in computer programs executing on programmable computers that each include a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. Program code is applied to data entered using the input device to perform the functions described above and to generate output information. The output information is applied to one or more output devices.
Each program is preferably implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the programs can be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language.
Each such computer program is preferably stored on a storage medium or device (e.g., ROM or magnetic diskette) that is readable by a general or special purpose programmable computer for configuring and operating the computer when the storage medium or device is read by the computer to perform the procedures described in this document. The system may also be considered to be implemented as a computer-readable storage medium, configured with a computer program, where the
Boothby David J.
Daley Robert C.
Marien John R.
Black Thomas
Fish & Richardson P.C.
Jung David Yink
Pumatech, Inc.
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