Object management system for digital libraries

• US 6,035,303 A
• Filed: 02/02/1998
• Issued: 03/07/2000
• Est. Priority Date: 02/02/1998
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Doong, Jane Ku, Baer, William Joseph, Parrish, Ronald Elliott, Hu, Jung-hsin Eva, Kauffman, Steven Victor, Lewis, Lara Marie
• Primary Examiner(s): HO, RUAY L
• Application Number:
  US09/017,400
• Time in Patent Office: 764 Days
• Field of Search: 707/1-10, 707/100-104, 707/200-206, 709/701, 709/245, 709/303, 345/333, 345/348, 714/38, 710/43, 380/49
• US Class Current: 1/1
• CPC Class Codes: G06F 16/289 Object oriented databases
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure

Abstract

An object management system for storing persistent object oriented objects, includes an object vault, a structural type manager and a digital library. The object vault is connected to the structural type manager and the digital library is connected to the structural type manager. An application program is connected to the object vault. Objects to be stored are represented as a Key Value Dictionary (KVD) in which attributes, or metadata, relating to the objects are stored as key-value pairs. Objects are categorized as having different structural types in which certain attributes for objects having the same structural type are cataloged to facilitate indexing and searching for the objects. The structural type manager maintains a mapping between structural types and a subset of keys for the structural types as well as corresponding database references for cataloging the object attributes. Also disclosed is a method of storing objects in the digital library where the corresponding database references for the subset of keys are retrieved from the structural type manager. The values corresponding to the subset of keys are retrieved from the Key Value Dictionary and stored in the library catalog. The Key Value Dictionary is serialized and stored in the digital library, and a signature is returned. The object stored in the digital library is retrieved by locating the objected based on the cataloged key values. Preferably the persistent objects are Java programming language objects.

Claims

1. An object management system for storing objects having a predetermined structural type, comprising:

an object vault;

a storage unit; and

a structural type manager, wherein the object vault, the structural type manager and the storage unit are connected to each other, and the object vault stores the object in the storage unit based on information in the structural type manager and according to the structural type of the object.

2. An object management system according to claim 1, wherein the storage unit is a digital library.

3. An object management system according to claim 2, wherein the digital library comprises:

a library client having a client storage area;

an object server having an object storage area; and

a library server including a library catalog, connected to the object server and the library client, wherein the library and object servers are in a distributed arrangement with the library client.

4. An object management system according to claim 2, further comprising an object-class interface, wherein the digital library is connected to the object vault and the structural type manager through the object-class interface.

5. An object management system according to claim 2, wherein the object vault retrieves:

the object from the digital library in response to a request for the object and receipt of a signature for the object.

6. An object management system according to claim 2, wherein the object vault comprises:

means to modify the object in the digital library.

7. An object management system according to claim 1, wherein the object is represented by a Key Value Dictionary (KVD), the KVD being a subclass of a dictionary, the dictionary including a unique key associated with one or more values, the KVD including a structural type key, wherein a value associated with the structural type key is one of a plurality of structural types.

8. An object management system according to claim 7, wherein the dictionary is a hash table.

9. An object management system according to claim 7, wherein the structural type manager comprises a mapping unit associating a key of the KVD with a database table and a column within the database table, wherein the value associated with the key is recorded said column within the database table.

10. An object management system according to claim 7, wherein the structural type manager comprises:

means for receiving the structural type key of the KVD;

means for retrieving a value associated with the received structural type key, the value being a structural type;

means for identifying a key associated with the said structural type indicated by the retrieved value;

means for retrieving an indicator of a database and an indicator of a column corresponding to the identified key; and

means for storing the a value of the KVD associated with the identified key in the database and column indicated by the database and column indicators, respectively.

11. An object management system according to claim 1, wherein said object is a Java object.

12. An object management system according to claim 1, wherein the structural type manager comprises:

a first object oriented method to retrieve a database table identifier for a specified structural type;

a second object oriented method to retrieve an ordered list of key names for a specified structural type; and

a third object oriented method to retrieve an ordered list of table columns for keys defined for a specified structural type.

13. An object management system according to claim 12, wherein the structural type manager further comprises:

a fourth object oriented method to create a structural type map;

a fifth object oriented method to create an attribute key for an existing structural type;

a sixth object oriented method to remove the attribute key; and

a seventh object oriented method to remove structural type map.

14. A method of storing an object in an object management system having an object vault, a storage unit and a structural type manager, the method comprising:

(a) receiving the object at the object vault;

(b) retrieving from the object a value indicating a structural type of the object;

(c) retrieving from the structural type manager an indicator of an attribute associated with the structural type of the object, wherein the attribute is to be stored in the digital library;

(d) identifying a location where a value of the indicated attribute is to be stored;

(e) retrieving from the object the value of the indicated attribute;

(f) storing the retrieved value of the object in the identified location; and

(g) storing the object in the storage unit.

15. A method according to claim 14, further comprising:

(h) serializing the object into a binary large object (blob);

(i) storing the blob in the storage unit; and

(j) generating a signature identifying a storage location of the stored object and returning the signature to the object vault.

16. A method according to claim 15, wherein said object is a Java object.

17. A method according to claim 14, wherein the storage unit is a digital library.

18. A method according to claim 14, wherein the storage unit is a database.

19. A method according to claim 14, wherein said object is a Java object.

20. In an object management system having an object vault, a storage unit and a structural type manager, a method of retrieving an object comprising:

(a) sending to the object vault a signature corresponding to the object;

(b) querying the storage unit in response to the signature, to locate the object in the storage unit and identifying an attribute and a corresponding value satisfying the query;

(c) retrieving from the digital library a binary large object (blob) corresponding to the located object; and

(d) constructing the object from the retrieved blob.

21. A computer program product for an object management system including an object vault, a structural type manager and a storage unit having an object server and a library server employing a database;

wherein the object vault is connected to the structural type manager and the digital library, and the structural type manager is connected to the digital library;

the computer program product including a computer readable medium comprising;

a computer-readable object vault code; and

a computer-readable structural type manager code;

wherein the object vault code causes a value of a structural type indicator of the object to be sent to the structural type manager code in response to the object vault receiving an object for storage in the storage unit;

wherein the structural type manager includes a mapping of the structural type indicator to a location within the database, and in response to receipt of the value of the structural type indicator the structural type manager code causes an attribute for the structural type and a database identifier for the database in which a value of the attribute is to be stored, to be returned to the object vault; and

wherein the object vault code directs storage of the value of the object associated with the returned attribute into the database location according to the database identifier, the object vault codes causes the object to be stored in the storage unit; and

returns a identifier for the stored object.