Simplified relational database extension to DBM hash tables and method for using same

• US 7,051,041 B1
• Filed: 10/21/2002
• Issued: 05/23/2006
• Est. Priority Date: 10/21/2002
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Miller, Thomas M.
• Primary Examiner(s): AMSBURY, WAYNE P
• Application Number:
  US10/273,990
• Time in Patent Office: 1,310 Days
• Field of Search: 707/102
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2343 Locking methods, e.g. distributed locking or locking implementation details
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

Abstract

DBM files represent a quick and relatively standard method of retrieving data. The DBM files essentially contain a two-column table representing a key/value pair. The simplified relational database extension (SRDE) design described herein extends the value column to be further divided into indexed columns that can be manipulated using a modified SQL interface. SRDE offers a simple setup and maintenance scheme, provides a rich set of regular expression matching that can be applied to all searches.

Claims

1. An extended database management (DBM) database, comprising:

a DBM database having a schema defining a plurality of table records, each record having a structure defined by a filename, a number of columns, a key field, and an optional external field, wherein the DBM database comprises a plurality of DBM index and DBM data files, each index file corresponding to a data file and optional external data files, wherein the DBM data files have limited memory allocation for storing data associated with each record and the external data files are capable of storing data larger than can be stored in the DBM data files;

a front end to the DBM database using structured query language SQL calls to select records in the DBM database; and

means for locking and unlocking the DBM database to maintain database integrity during database access, wherein the means for locking and unlocking uses files residing on the system as semaphores to identify a locked/unlocked state.

2. The extended DBM database as recited in claim 1, wherein the means for locking and unlocking the DBM database uses a table level resource locking mechanism to lock writes and allow dirty reads of the data.

3. The extended DBM database as recited in claim 1, wherein use of an external data file in a table record is defined in the schema, and the external data files store data larger than 1024 bytes and a pointer in the DBM data file identifies the external data file and location.

4. The extended DBM database as recited in claim 3, wherein the means for locking and unlocking the DBM database uses a table level resource locking mechanism to lock writes and allow dirty reads of the data.

5. The extended DBM database as recited in claim 1, wherein the front end to the DBM database performs a plurality of functions extending native DBM functionality.

6. The extended DBM database as recited in claim 5, wherein the plurality of functions is selected from the group consisting of table creation, record selection, record insertion, record update, record deletion, record importation, and record exportation.

7. The extended DBM database as recited in claim 6, wherein the means for locking and unlocking the DBM database uses a table level resource locking mechanism to lock writes and allow dirty reads of the data.

8. The extended DBM database as recited in claim 1, the front end further comprising:

a first section of computer code for maintaining record structure;

a second section of computer code for performing SQL parsing;

a third section of computer code for locking the DBM database;

a fourth section of computer code for performing record insertion;

a fifth section of computer code for performing record update;

a sixth section of computer code for performing record deletion; and

a seventh section of computer code for performing record selection.

9. The extended DBM database as recited in claim 8, wherein the front end is coded in Per1 script.

10. A method for extending a DBM database using a structured query language (SQL) front end, the method comprising:

generating a DBM database schema for a DBM database, the schema defining a plurality of table records, each record having a structure defined by a filename, a number of columns, a key field, and an optional external field, wherein the DBM database comprises a plurality of DBM index and DBM data files, each index file corresponding to a data file and optional external data files, wherein the DBM data files have limited memory allocation for storing data associated with each record and the external data files are capable of storing data larger than can be stored in the DBM data file;

accessing records in the DBM database using a SQL front end, wherein the front end performs a plurality of functions extending native DBM functionality;

acquiring a resource lock of a table record, if necessary, to maintain database integrity before accessing the table record; and

releasing a resource lock of a table record after accessing the table record, wherein files used as semaphores identify a locked or unlocked state of the table record.

11. The method as recited in claim 10, further comprising:

using a regular expression to search the DBM database; and

selecting at least one item in the DBM database based on a return value of the regular expression search.

12. The method as recited in claim 10, wherein the plurality of functions is selected from the group consisting of table creation, record selection, record insertion, record update, record deletion, record importation, and record exportation.

13. The method as recited in claim 10, wherein the accessing step further comprises:

accessing a table record in a DBM data file having a pointer to an external file; and

accessing a record from the external file pointed to by the accessed table record.

14. The method as recited in claim 10, wherein the front end is coded in Per1 script.

15. A method for using an extended a database management (DBM) database having a structured query language (SQL) front end, the method comprising:

accessing records in the DBM database using a SQL front end, wherein the DBM database is generated using a DBM database schema for a DBM database, the schema defining a plurality of table records, each record having a structure defined by a filename, a number of columns, a key field, and an optional external field, wherein the DBM database comprises a plurality of DBM index and DBM data files, each index file corresponding to a data file and optional external data files, wherein the DBM data files have limited memory allocation for storing data associated with each record and the external data files are capable of storing data larger than can be stored in the DBM data file, wherein the front end performs a plurality of functions extending native DBM functionality;

acquiring a resource lock of a table record, if necessary, to maintain database integrity before accessing the table record; and

releasing the resource lock of a table record, if necessary, after accessing the table record, wherein files used as semaphores identify a locked or unlocked state of the table record.

16. The method as recited in claim 15, wherein accessing records further comprises using a regular expression in a SQL command as selection criteria for accessed records.

17. The method as recited in claim 15, wherein accessing records further comprises retrieving selected records, wherein the retrieved records are returned as associative arrays.

18. The method as recited in claim 15, wherein the DBM database is accessed using native DBM commands without the assistance of a database management service.

19. The method as recited in claim 15, wherein the accessing records further comprises:

accessing a table record in a DBM data file having a pointer to an external file; and

accessing a record from the external file pointed to by the accessed table record.

20. The method as recited in claim 15, wherein the DBM database resides on a host system and accessing records utilizes security methods of the host system.

21. A computer-based application using a simplified relational database

extension, comprising:

computer application code running on a computing device, the application computer code being used for a selected application and needing access to a database;

a database accessible to the computer application code, the database being implemented in a DBM database for storing and retrieving data needed by the computer-based application, the DBM database developed from a schema defining a plurality of table records, each record having a structure defined by a filename, a number of columns, a key field, and an optional external field, wherein the DBM database comprises a plurality of DBM index and DBM data files, each index file corresponding to a data file and optional external data files, wherein the DBM data files have limited memory allocation for storing data associated with each record and the external data files are capable of storing data larger than can be stored in the DBM data files, and wherein data stored in the DBM is dependent on the computer-based application; and

a front end to the DBM database using structured query language SQL calls to select records in the DBM database, wherein the front end is used by the computer-based application as an interface to the DBM database.

22. The computer-based application as recited in claim 21, wherein use of an external data file in a table record is defined in the schema, and the external data files store data larger than 1024 bytes and a pointer in the DBM data file identifies the external data file and location.

23. The computer-based application as recited in claim 22, further comprising:

means for locking and unlocking the DBM database to maintain database integrity during database access.

24. The computer-based application as recited in claim 23, wherein the means for locking and unlocking the DBM database uses a table level resource locking mechanism to lock writes and allow dirty reads of the data.

25. The computer-based application as recited in claim 24, wherein the means for locking and unlocking uses files residing on the system as semaphores to identify a locked/unlocked state.

26. The computer-based application as recited in claim 21, wherein the front end to the DBM database performs a plurality of functions extending native DBM functionality.

27. The computer-based application as recited in claim 26, wherein the plurality of functions is selected from the group consisting of table creation, record selection, record insertion, record update, record deletion, record importation, and record exportation.

28. The computer-based application as recited in claim 21, further comprising:

means for locking and unlocking the DBM database to maintain database integrity during database access.

29. The computer-based application as recited in claim 25, wherein the means for locking and unlocking the DBM database uses a table level resource locking mechanism to lock writes and allow dirty reads of the data.

30. The computer-based application as recited in claim 29, wherein the means for locking and unlocking uses files residing on the system as semaphores to identify a locked/unlocked state.

31. The computer-based application as recited in claim 21, the front end further comprising:

a first section of computer code for maintaining record structure;

a second section of computer code for performing SQL parsing;

a third section of computer code for locking the DBM database;

a fourth section of computer code for performing record insertion;

a fifth section of computer code for performing record update;

a sixth section of computer code for performing record deletion; and

a seventh section of computer code for performing record selection.

32. The computer-based application as recited in claim 31, wherein the front end is coded in Per1 script.

33. An extended database management (DBM) database, comprising:

a DBM database having a schema defining a plurality of table records, each record having a structure defined by a filename, a number of columns, and a key field, wherein the DBM database comprises a plurality of DBM index and DBM data files, each index file corresponding to a data file; and

a front end to the DBM database using structured query language SQL calls to select records in the DBM database, wherein typical database management functions are performed without the assistance of a database management service.

34. The extended DBM database as recited in claim 33, wherein the DBM database resides on a host system and accesses records utilizing security methods of the host system.

35. The extended DBM database as recited in claim 33, wherein records are accessed by retrieving selected records, wherein the retrieved records are returned as associative arrays, and wherein the retrieval method is data type-independent.

36. The extended DBM database as recited in claim 35, wherein records are accessed using a regular expression in a SQL command as selection criteria for accessed records.

37. The extended DBM database as recited in claim 33, further comprising:

means for locking and unlocking the DBM database to maintain database integrity during database access, wherein the means for locking and unlocking the DBM database uses a table level resource locking mechanism to lock writes and allow dirty reads of the data.

38. An extended database management (DBM) database, comprising:

a DBM database having a schema defining a plurality of table records, each record having a structure defined by a filename, a number of columns, and a key field, wherein the DBM database comprises a plurality of DBM index and DBM data files, each index file corresponding to a data file; and

a front end to the DBM database using structured query language SQL calls to select records in the DBM database, wherein records are accessed by retrieving selected records, the retrieved records are returned as associative arrays, the retrieval method is data type-independent and the typical database management functions are performed without the assistance of a database management service.

39. The extended DBM database as recited in claim 38, wherein the DBM database resides on a host system and accesses records utilizing security methods of the host system.

40. The extended DBM database as recited in claim 38, wherein the front end allows retrieval of data from the DBM database using a regular expression in a SQL command as selection criteria for accessed records.

41. The extended DBM database as recited in claim 38, further comprising:

means for locking and unlocking the DBM database to maintain database integrity during database access, wherein the means for locking and unlocking the DBM database uses a table level resource locking mechanism to lock writes and allow dirty reads of the data.