Data processing: database and file management or data structures – Database design – Data structure types
Reexamination Certificate
1999-08-06
2002-06-04
Breene, John (Department: 2177)
Data processing: database and file management or data structures
Database design
Data structure types
C709S229000
Reexamination Certificate
active
06401103
ABSTRACT:
BACKGROUND OF THE INVENTION
1. The Field of the Invention
The present invention relates to data base management, and more specifically, to mechanisms for accessing and editing records of a database across the Internet while maintaining data integrity.
2. The Relevant Technology
Conventional mainframe databases have proven extremely useful and necessary for data management by various entities. Mainframe databases must be extremely reliable and are in many instances capable of handling large transactional loads. One example of such a database management system is the Information Management System (IMS) available from IBM Corp., Armonk, N.Y. An IMS system[s] allows access to one or more databases in order for users to interact with the data maintained on the database. The majority of user access involves transaction. Transactions may involve incorporating business logic into database updates. Integrity and verification of database updates are protected by ensuring that business logic has been applied and that editing rules are confirmed. In this manner, database updates are guaranteed to be correct.
Throughout, reference will be made to an IMS database management system running on a mainframe computer with accompanying middleware acting as World Wide Web server for allowing Internet access to the database. This is an exemplary environment only and the invention presented hereafter will apply to any Internet accessible database or other database in a stateless environment. For example, a web-accessible relational database, such as Oracle 8i, IBM DB2, or Microsoft SQL Server 7.0, would encounter the same problems presented hereafter and could equally make use of the present invention. Furthermore, the present invention provides benefit in any stateless situation when it is unknown at the time of a database request, when, if ever, the requestor will return with modified data for update into the database.
Sensitive information, such as payroll systems, are not allowed to be accessed or updated absent this form of guarantee. For example, in a financial transfer between two accounts, one account is credited and another account is debited. The system must handle this transfer as one unit even though accessing two independent databases. In order to ensure that each database update is correct, this transaction must be verified for both databases in order to confirm and complete the transaction. Otherwise, the transaction is not allowed to proceed.
IMS systems are frequently made accessible over closed networks such as LANs and WANs in order to enable users on the network to make transactions on an enterprise's database. More recently, IMS systems have been made accessible to users communicating across the Internet to enable user transactions on the database. Such Internet-enabled use provides users physically remote to the enterprise with the ability to transact with the databases.
Generally, these outside users are allowed to access data that does not have critical data elements. Such nonsensitive data need not have business data, database logic, and business rules applied thereto. Nonsensitive data may include, for example, a customer's name, address file, telephone number etc. Thus, users such as a customer are able to access the database through the Internet and are provided with the ability to alter only nonsensitive data.
Generally, outside users access the IMS system through conventional browser technology. Through the browser, the user may request specific data from the IMS system. In response, the IMS accesses and transmits the nonsensitive information to be displayed by the browser for the user's review. The user may then access the displayed information, update it according to the user's needs, and transmit the updated data back to the IMS system.
While standard business database logic and rules need not be applied to nonsensitive information, any modifications to the data must still follow standard integrity, serialization, and locking rules. For instance, conventional locking standards require that when a user retrieves data that is to be updated, the data must be locked so that it cannot be changed until the update is completed. After the update is completed, the data is sent back to the IMS system, which commits the changes to the system. Because the data was locked, the data is maintained internally consistent until the changes are logged and the data is again opened for user access.
An Internet system for accessing data from a database is absent many advantages of a conventional network system. For example, a web user does not necessarily stay connected to the system during a transaction, and the system is not able to track what the user is doing with data downloaded to the web browser. Additionally, the system does not know when a web user intends to enter data or update data, nor does the system know if or when the web user will return any updates or if the web user has terminated a connection with the system. Thus, conventional locking systems are not effective in an Internet environment. A locking mechanism is generally unable to lock data upon transmission of the data to a web browser, because the system does not know when to unlock the data.
A conventional technique known as optimistic locking has been used to eliminate the need for locking data for long periods of time during data transmissions over the web. Optimistic locking assumes that the data need not be locked, because it is not likely that anyone else is going to change the data. Therefore, the data is not locked, but is checked to verify whether anyone has changed any data before the web user makes the update.
Optimistic locking requires a host to remember an initial state of all data sent by the host to the web user. When the web user returns updated data, the host checks the data to verify that the original data sent to the user is still current. If so, the updated data is verified as being based on the current data, and is entered into the system. If the original data has been modified, the update is not allowed to occur, and the user is notified of the modified data.
Optimistic locking mechanisms are very effective in dealing with database updates in certain instances, such as when dealing with relatively few active web users. For example, a host dealing with only ten users at a time can easily accommodate and remember ten initial states. Difficulty arises when a host must dedicate resources to retaining thousands or millions of states. Systems open to Internet access are such an environment, as the web allows millions of users to access an IMS system at any given time. In order to accommodate such vast numbers of web users, a host would be forced to maintain an elaborate state table and dedicate substantial resources to maintaining the state table. Such a burden on a host's resources may easily exceed what the host is effectively able to manage.
Thus, from the above discussion, it is apparent that it would be advantageous to accommodate Internet-enabled transactions on a database, while retaining the advantages of optimistic locking mechanisms. It would also be advantageous to provide an optimistic locking mechanism that is efficient and highly scalable, in order to accommodate the large numbers of users that may access a database over the Internet. It would similarly be an advantage to provide an optimistic locking mechanism that operates in conjunction with conventional web browsers and with conventional IMS systems. It would be a further advantage to provide an optimistic locking system that is capable of reliably and cost-effectively implementing Internet access of an IMS system.
OBJECT AND BRIEF SUMMARY OF THE INVENTION
The apparatus of the present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available data integrity verification and locking mechanisms. Thus, it is an overall objective of the present invention to prov
Ho Shyh-Mei
Watts Vern Lee
Ali Mohammad
Breene John
International Business Machines - Corporation
Madson & Metcalf
Thompson John R.
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