Database system with control for loading definition data for storage units

• US 5,426,782 A
• Filed: 03/03/1993
• Issued: 06/20/1995
• Est. Priority Date: 03/04/1992
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Shiga, Shoji
• Primary Examiner(s): Chan, Eddie P.
• Application Number:
  US08/026,155
• Time in Patent Office: 839 Days
• Field of Search: 395/600, 395/650, 395/700
• US Class Current: 707/736
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: Y10S 707/99956 File allocation

Abstract

The database system includes a definition data file to store definition data for the storage units established in the database file, and loads the definition data from such definition data file to the definition data storage section, refers to the loaded definition data, and opens, updates/retrieves and closes the database file. A re-loading judgment section judges whether or not the definition data for the storage units have been changed after loading definition data to the definition data storage section and before opening of the data base file and, if the definition data have been changed, directs re-loading of the definition data.

Claims

1. A database system comprising:

a database file provided with a plurality of storage units for storing data,

a storage unit definition means for establishing said storage units in said database file and changing definition data indicating the configuration of the storage units before the start of processing of said database file,

a definition data storage file for storing the definition data related to said storage units changed by said storage unit definition means,

a load and storage means for loading the definition data for the storage units from said definition data storage file and storing the loaded definition data,

a database processing means for performing opening, updating/retrieving and closing processing of said database file, with reference to the definition data for said storage units loaded by said load and storage means from said definition data storage file,

a notification means for generating a notice of the definition data change each time said storage unit definition means establishes said storage units and changes the definition data, and

a re-loading judgment means responsive to the notice of definition data change, for judging whether any definition data for the storage units in the database file have been loaded to said load and storage means and before opening of said database file, and outputting a re-loading direction to said database processing means and before opening of said database file for re-loading said definition data to said load and storage means when the definition data have been changed.

2. The database system of claim 1 further comprising a re-loading direction registration means for registering and generating a re-loading direction for re-loading of said definition data output from said re-loading judgment means, and wherein

said database processing means refers to said re-loading direction registration means when it refers to said definition data storage file and, when any re-loading direction is found, directing said load and storage means to re-load the definition data from said definition data storage file.

3. The database system of claim 2, wherein said database processing means activates said load and storage means upon starting of accessing to said database file or according to the re-loading direction from said re-loading judgment means.