System and method for implementing database cursors in a client/server environment

• US 5,835,904 A
• Filed: 04/10/1997
• Issued: 11/10/1998
• Est. Priority Date: 10/31/1995
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Vicik, Frederic O., Divringi, Lale R.
• Primary Examiner(s): Kulik, Paul V.
• Application Number:
  US08/838,610
• Time in Patent Office: 579 Days
• Field of Search: 707/1, 707/8, 707/10, 395/200.33
• US Class Current: 1/1
• CPC Class Codes: G06F 16/252 between a Database Management System and a front-end application
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database

Abstract

A system and method for implementing database cursors at the server in a client/server environment is disclosed. In operation, the system and method for implementing the database cursors is compatible with existing client/server database search engines but provides for increased control over cursor lock options, an ability to share cursors and search plans across multiple nodes in a network, and an increase in the overall operating efficiency of a database application. The invention is directed to cursors for all types of collections or compilations of data in a client/server database environment.

Claims

1. A database management system of the type which may be executed by a server computer having a database and a network interface module operating in a client/server network environment, comprising:

a client interface operable to parse a communication packet received from a client on the network through the network interface module, said communication packet containing a client database request;

a search engine module including a query optimizer operable to select an optimum process for searching the database, said search engine module also operable to produce an execution plan of instructions on how to search the database to produce a result set;

data manager and kernel components responsive to said instructions from the search engine and operable to access data in the database in accordance with said instructions to process the client database request;

a sequencer operable to receive the client database request from the client interface and to invoke the search engine and data manager in the proper sequence to perform the database request; and

a cursor module operable to receive a cursor request from a client through said network interface, generate data structures representative of said client'"'"'s position within the result set, and maintain said data structures on said server.

2. A client computer in a database management system of the type which may be executed by client and server computers, comprising:

a client application operable to provide database commands in the form of data structures;

a cursor router positioned on said client computer and operable to intercept command data structures from said client application and to route said command data structures representing requests for database cursors; and

a cursor module operable to receive a cursor request from a client application through said cursor router, generate data structures representative of said client'"'"'s position within the result set, and maintain said data structures on said client.

3. A network database system including database cursors comprising:

at least one client computer including a database client application, an operating system, and a network interface;

at least one server computer including a database management system, an operating system, a server cursor module and a network interface;

a network connecting said at least one client computer to said at least one server;

a cursor router positioned on said client computer, said cursor router further comprising

an intercepting means for intercepting data representing requests for cursors,

an evaluating means for generating a router signal representative of whether a cursor module is present on said server,

a routing means for routing cursor requests to a client cursor module or to a server cursor module depending on the presence of said router signal;

said cursor module on said client computer receiving cursor requests, generating data structures representative of said client application'"'"'s position within a set of data, and storing said data structures on said client;

said cursor module on said server computer receiving cursor requests through said network, generating data structures representative of said client application'"'"'s position within a set of data, and storing said data structures on said server.