System and method for accessing non-relational data by relational access methods

• US 20010018684A1
• Filed: 02/23/2001
• Published: 08/30/2001
• Est. Priority Date: 02/25/2000
• Status: Abandoned Application

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Mild, Wilhelm, Franzki, Ingo
• Application Number:
  US09/791,924
• Publication Number:
  US 20010018684A1
• Time in Patent Office: Days
• US Class Current: 707/1
• CPC Class Codes: G06F 16/284 Relational databases

Abstract

The present invention relates to a system and method for accessing non-relational data stored in records on a host system by a relational access method. The implementation of a relational interface component allows data transformation and type conversion and gives a relational interface to non-relational data. An integrated mapping component is used to define the relational structure of non-relational records or data. This relational structure is used by the application program or database request. The mapping component allows one to define columns with their characteristic (i.e. byte offset, data type, length). The definitions can be grouped in maps equivalent to a relational table and views representing a subset of the columns defined in a map. Multiple different maps and views can be defined for one record. The information of the maps, columns and views are stored in a repository. The inventive interface component uses the definitions stored in the repository to access the non-relational data and splits the records. Preferably based on the SQL language non-relational data like VSAM data can be accessed from any program using the relational interface component. The original non-relational data remains unchanged and older programs work without changes. The present invention gives new possibilities for host based programs using non-relational access methods and supports the integration, transition and migration into relational environments.

Claims

1. A method for accessing data stored in records having a non-relational data structure by means of a program using a relational access method, each of said records containing at least one data element, said method comprising the steps of:

gathering information that describes the non-relational data structure of said records;

generating a map that maps said non-relational data structure to a relational data structure having columns and rows;

storing said map in a storage medium; and

receiving a relational request specifying a map and executing said request using an interface component that performs the steps of;

accessing the map specified in said relational request to retrieve column information for accessing said data element from said map;

generating an optimized non-relational request using column information for accessing said data element; and

executing said optimized non-relational request via a non-relational access method.

2. A method according to

claim 1

, wherein said non-relational structure information is obtained from source code.

3. A method according to

claim 1

, wherein said non-relational structure information is obtained from a COBOL copybook.

4. A method according to

claim 1

, wherein said non-relational structure information is obtained from a C header file.

5. A method according to

claim 1

, further comprising the steps of:

generating a view based on said map that includes a subset of the columns defined in said map; and

storing said view in a storage medium.

6. A method according to

claim 5

, wherein said step of generating a map and said step of generating a view are automatically performed by a mapping tool.

7. A method according to

claim 5

, wherein said map and said view are stored in a mapping repository.

8. A method according to

claim 1

, wherein each defined addressable data element in a record is defined as a separate column.

9. A method according to 1, wherein each column is defined by an arbitrary name for the column, offset within the record, length of field in the record and data type.

10. A method according to

claim 1

, wherein each record or part thereof is defined in multiple maps.

11. A method according to

claim 1

, wherein each map or part thereof is defined in multiple views containing a subset of columns defined in the map.

12. A method according to

claim 1

, wherein said relational request is a SQL request that is specified by one or more columns and the name of a related map or view.

13. A computer program product containing software code for executing the method of

claim 1

when said program product is run on a digital computer.

14. A method for accessing data stored in records having a non-relational data structure that includes at least one data element by means of a program using a relational access method, each record or part thereof being defined in a map in a relational view having columns and rows, said method comprising the steps of:

receiving a relational request specifying a map and executing said request using an interface component that performs the following steps;

accessing the map specified in said relational request;

retrieving column information for accessing said data element from said map;

generating an optimized non-relational request using said column information for accessing said data element; and

executing said optimized non-relational request via a non-relational access method.

15. A computer program product containing software code for executing the method of

claim 14

when said program product is run on a digital computer.

16. A system for accessing data stored in records having a non-relational data structure via a program using a relational access method, comprising:

a repository containing a map or view that maps said non-relational data structure to a relational data structure having columns and rows; and

an interface component for mapping relational requests from said program to non-relational requests by means of information from said repository.

17. A method for mapping a non-relational data structure of a record to a relational data structure, comprising the steps of:

gathering information that describes the non-relational data structure of said record;

generating a map that maps said non-relational data structure to a relational data structure having columns and rows; and

storing said map in a storage medium.

18. A method according to

claim 17

, further comprising the steps of:

generating a view based on said map that includes a subset of data elements defined in said map; and

storing said view in a storage medium.

19. A computer program product containing software code for executing the method of

claim 18

when said program product is run on a digital computer.