Persistent object mapping system and method with abstract schema mapper

• US 5,729,739 A
• Filed: 12/08/1995
• Issued: 03/17/1998
• Est. Priority Date: 04/26/1994
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Gheith, Ahmed M., Sessions, Roger H., Copeland, George P., Cantin, Guylaine
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): Alam, Hosain T.
• Application Number:
  US08/569,550
• Time in Patent Office: 830 Days
• Field of Search: 395/613, 395/614, 395/683
• US Class Current: 1/1
• CPC Class Codes: G06F 9/4493 Object persistence
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure

Abstract

A system for mapping data between a selected object and a persistent medium in an object-oriented computer system is disclosed, wherein the data is manipulated by processing methods associated with the object. The system selects a target to which the data is to be mapped and converts the data invoking to an environment type in which the data is to be mapped. The system further constructs a mapping method associated with the mapping request for mapping between the selected object and the persistent medium, where the method group consists of "store new", "store existing", "restore", and "delete". Further, a method is also disclosed for mapping a data structure between an object, which is in a class object, and a persistent medium in an object-oriented environment. The method includes receiving a request to map the data structure between the object and the persistent medium at the object. The request is sent from the identification object to the class object. A plurality of data mapping methods is then defined for each persistent object Then, a request to invoke one of the plurality of mapping methods is constructed. After which, one of the plurality of mapping methods for mapping the data structure between the object and the persistent medium is performed.

Claims

1. A data processing system for mapping data between a dynamic state and a persistent state of a persistent object, wherein said dynamic state exists within a first environment and said persistent state exists within one of a plurality of persistent media, and further wherein said one of a plurality of persistent media exists within a second environment, comprising:

means for associating said persistent object with at least one of said plurality of persistent media;

means for constructing a mapping method for each of said plurality of persistent media associated with said persistent object, in response to said persistent object and said first and second environments, wherein each said constructed mapping method includes language usable by a type of said each of said plurality of persistent media; and

means for mapping data between a dynamic state and a persistent state of a persistent object utilizing said mapping method constructing means, wherein said dynamic state exists within a first environment and said persistent state exists within said at least one of said plurality of persistent media, and further wherein said at least one of said plurality of persistent media exists within a second environment.

2. The system of claim 1, wherein said means for constructing a mapping method is invoked upon the instantiation of a persistent object.

3. The system of claim 1, wherein said constructed mapping method comprises a "store new" method.

4. The system of claim 1, wherein said constructed mapping method comprises a "store existing" method.

5. The system of claim 1, wherein said constructed mapping method comprises a "restore" method.

6. The system of claim 1, wherein said constructed mapping method comprises a "delete" method.

7. A data processing system as set forth in claim 1, said mapping method constructing means further comprising:

means for defining a mapping class having a generic interface and a mapping method, for each of said plurality of persistent media associated with said persistent object;

means for adapting said mapping method within each said mapping class for said persistent object; and

means for instantiating a mapping object belonging to each said mapping class such that said adapted mapping method may be invoked utilizing said generic interface.

8. The data processing system of claim 1, wherein said at least one of said plurality of persistent media comprises a relational database and further wherein said language usable by a type of said each of said plurality of persistent media comprises a structured query language.

9. A method within a data processing system of mapping data between a dynamic state and a persistent state of a persistent object, wherein said dynamic state exists within a first environment and said persistent state exists within one of a plurality of persistent media, and further wherein said one of a plurality of persistent media exists within a second environment, said method comprising the steps of:

associating said persistent object with at least one of said plurality of persistent media;

constructing a mapping method for each of said plurality of persistent media associated with said persistent object, in response to said persistent object and said first and second environments, wherein each said constructed mapping method includes language usable by a type of said each of said plurality of persistent media; and

mapping data between a dynamic state and a persistent state of a persistent object utilizing said constructed mapping method, wherein said dynamic state exists within a first environment and said persistent state exists within said at least one of said plurality of persistent media, and further wherein said at least one of said plurality of persistent media exists within a second environment.

10. The method of claim 9, wherein said mapping method includes a method of mapping said data in a new location within one of said plurality of persistent media said method further comprising the steps of:

constructing a new location within a persistent medium for receiving said data;

converting said data in response to an environment type compatible with said persistent medium; and

storing said converted data in said new location within said persistent medium.

11. The method of claim 9, wherein said mapping method includes a method of mapping said data in an existing location within one of said plurality of persistent media, said method further comprising the steps of:

converting said data in response to an environment type compatible with a persistent medium; and

storing said converted data in said existing location within said persistent medium.

12. The method of claim 9, wherein said mapping method includes a method of restoring said data mapped in an existing location within one of said plurality of persistent media to said persistent object, said method further comprising the steps of:

recalling said data from a location within a persistent medium;

converting said data to an environment type compatible with said persistent object; and

storing said converted data in said persistent object.

13. The method of claim 9, wherein said mapping method includes a method of deleting said data from an existing location within one of said plurality of persistent media, said method further comprising the step of:

deleting said data from said existing location within a persistent medium.

14. A method as set forth in claim 9, said step of constructing a mapping method further comprises the steps of:

defining a mapping class having a generic interface and a mapping method, for each of said plurality of persistent media associated with said persistent object;

adapting said mapping method within each said mapping class for said persistent object; and

instantiating a mapping object belonging to each said mapping class such that said adapted mapping method may be invoked utilizing said generic interface.

15. A computer program product to be utilized within a data processing system for mapping data between a dynamic state and a persistent state of a persistent object, wherein said dynamic state exists within a first environment and said persistent state exists within one of a plurality of persistent media, and further wherein said one of a plurality of persistent media exists within a second environment, comprising:

media usable by said data processing system for storing and executing instruction means;

instruction means, embodied within said media, for associating said persistent object with at least one of said plurality of persistent media;

instruction means, embodied within said media, for constructing a mapping method for each of said plurality of persistent media associated with said persistent object, in response to said persistent object and said first and second environments, wherein each said constructed mapping method includes language usable by a type of said each of said plurality of persistent media; and

instruction means, embodied within said media, for mapping data between a dynamic state and a persistent state of a persistent object utilizing said mapping method constructing instruction means, wherein said dynamic state exists within a first environment and said persistent state exists within said at least one of said plurality of persistent media, and further wherein said at least one of said plurality of persistent media exists within a second environment.

16. A computer program product as set forth in claim 15, said mapping method constructing instruction means further comprising:

instruction means, embodied within said media, for defining a mapping class having a generic interface and a mapping method, for each of said plurality of persistent media associated with said persistent object;

instruction means, embodied within said media, for adapting said mapping method within each said mapping class for said persistent object; and

instruction means, embodied within said media, for instantiating a mapping object belonging to each said mapping class such that said adapted mapping method may be invoked utilizing said generic interface.