Methods and systems for object-based relational distributed databases

• US 5,560,005 A
• Filed: 02/25/1994
• Issued: 09/24/1996
• Est. Priority Date: 02/25/1994
• Status: Expired due to Term

• Current Assignee: WebMD Health Corporation
• Original Assignee: ActaMed Corp. (WebMD Health Corporation)
• Inventors: Daigle, Richard A., Miller, Barrick H., Schurenberg, Kurt, Hoover, Michael K.
• Primary Examiner(s): Heckler, Thomas M.
• Application Number:
  US08/202,493
• Time in Patent Office: 942 Days
• Field of Search: 395/200.03, 395/200.09, 395/200.1, 395/600, 395/700
• US Class Current: 1/1
• CPC Class Codes: G06F 16/245 Query processing
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor

Abstract

An object-based relational distributed database system and associated methods of operation that transforms data stored in a plurality of remote, heterogeneous user databases into a homogeneous data model is disclosed. Data stored in distributed, heterogeneous user database structures is homogenized by mapping into object attributes of predetermined instances of objects forming to a conceptual model that relates the various heterogeneous databases. The object attributes are stored in remote databases at client sites, which can be separate computer systems from the heterogeneous user databases or separate processes running on a computer system that maintains the heterogeneous user databases. The system stores location information and status information relating to the homogenized data in a centralized object broker for object management, thereby facilitating location and retrieval of data items from one or more of the remote, heterogeneous user databases.

Claims

1. A method of operating a distributed data processing system including a plurality of independent remotely located user computers that process user data in user databases and at least one object broker computer,

the user computers being interconnected with the object broker computer by data communication hardware over a data communication network,

the user computers being operative to perform data operations of storing, updating, and retrieving user data items in response to user commands, comprising the steps of:

(a) for a subject at one of the user computers for which data is to be processed in the system, creating an object instance by assigning a unique object identifier to data items associated with the subject by;

(a1) providing a global object identification address space corresponding to a range of object identifiers for association with a plurality of subjects; and

(a2) allocating a predetermined range of object identifiers within the global object identification address space to each remotely located user computer;

(b) storing the data items associated with the subject at the user computer in association with the object identifier;

(c) at the object broker computer, storing the locations of the user computers in a mapping table in association with object identifiers;

(d) in response to a query to the object broker computer for data relating to a particular subject in question, retrieving a selected object identifier for the subject in question;

(e) in response to retrieval of an object identifier for the subject in question in the preceding step, retrieving the location of a remote user computer associated with the selected object identifier; and

(f) retrieving data stored at the remote user computer associated with the selected object identifier via the data communication network.

2. The method of claim 1, wherein each of the remotely located user computers comprises a heterogeneous data structure, and further comprising the steps of:

at the user computers, mapping predetermined data items stored in the user computers to corresponding object attributes associated with a predetermined instance of an object;

storing the object attributes in an object attribute table in the remote user computers in association with object identifiers.

3. The method of claim 1, wherein the step of allocating a predetermined range of object identifiers is carried out at the object broker computer, and wherein a new object instance is created by assigning a unique object identifier from a predetermined range of object identifiers is carried out at the user computers.

4. The method of claim 1, wherein the query to the object broker originates at a first user computer, and the data associated with the selected object identifier is stored at a second user computer, and further comprising the step of communicating data retrieved, associated with the selected object identifier, to the object broker and then to the first user computer via the data communication network.

5. The method of claim 1, wherein the data items associated with the subject stored at the user computer in association with the object identifier are stored in an object attribute table.

6. The method of claim 5, wherein the remotely located user computers include at least one customer database and at least one remote database associated therewith, and wherein the object attribute table is stored in the remote database.

7. The method of claim 1, further comprising the step of maintaining an object index table at the object broker computer for relating at least one predetermined search term to at least one object identifier.

8. The method of claim 7, wherein the object index table for relating at least one predetermined search term to at least one object identifier is a relational base table, and further comprising the step of maintaining a junction index table relating object identifiers corresponding to a first class of objects to object identifiers corresponding to a second class of objects.

9. The method of claim 1, wherein the user computers are located at a user computer site including at least one customer database and at least one remote database associated therewith, the at least one remote database storing an object attribute table for relating object attributes to object identifiers, and wherein the object broker computer stores an object index table for relating at least one predetermined search term to at least one object identifier.

10. The method of claim 9, further comprising the steps of:

in response to an add request at one of the user computers to add a subject to the system, providing selected data items associated with the subject to be added from the customer database to the remote database;

at the remote database, carrying out the step of creating new object instance by assigning a new object identifier to data items associated with the subject;

communicating information relating the new object identifier to at least one corresponding search term to the object broker computer;

at the object broker computer, updating the object index table to reflect the association of the new object identifier, the corresponding search term;

at the object broker computer, updating the mapping table to reflect the location of the user computer that added the new object instance identified by the new object identifier.

11. The method of claim 9, further comprising the steps of:

in response to a search request at a querying one of the user computers to determine whether an object exists corresponding to a selected search term, communicating the selected search term to the object broker computer;

at the object broker computer, consulting the object index table to determine whether there is an object identifier associated with the selected search term;

in response to a determination that there is an object identifier associated with the selected search term, retrieving the corresponding object identifier;

providing a message to the querying user computer via the data communication network including the corresponding object identifier.

12. The method of claim 9, further comprising the steps of:

in response to a get request at a requesting one of the user computers based on a particular object identifier, communicating the particular object identifier to the object broker computer;

at the object broker computer, consulting the mapping table based on the particular object identifier to identify a particular remote database at a particular user computer site;

communicating a get message to the particular remote database at the particular user computer site including the particular object identifier;

at the particular remote database, consulting an object attribute table index to obtain retrieval information corresponding to the particular object identifier in the particular object attribute table;

retrieving object attributes associated with the particular object identifier from the particular object attribute table; and

communicating retrieved object attributes to the object broker computer and thence to the requesting user computer.

13. The method of claim 9, further comprising the steps of:

in response to a get all request at a requesting one of the user computers based on a particular object identifier that is related to one or more related object identifiers, communicating the particular object identifier to the object broker computer;

at the object broker computer, consulting an object index table that relates object identifiers of a first type to object identifiers of a second type to retrieve one or more related object identifiers associated with the particular object identifier;

at the object broker computer, consulting the mapping table based on retrieved related object identifiers to identify a one or more object attribute tables at one or more particular remote databases at one or more user computer sites containing data on the related object identifiers;

communicating a get message to the one or more remote databases including the related object identifiers;

at the one or more particular remote databases, consulting one or more object attribute table indexes to obtain retrieval information corresponding to the related object identifiers in the one or more object attribute tables;

retrieving object attributes associated with the related object identifiers from the one or more object attribute tables; and

communicating retrieved object attributes to the object broker computer and thence to the requesting user computer.

14. The method of claim 9, further comprising the steps of:

in response to an update request at an updating one of the user computers based on a particular object identifier for which one or more object attributes are to be updated, communicating the particular object identifier to the object broker computer together with the one or more object attributes to be updated;

at the object broker computer, consulting the mapping table based the particular object identifier to identify an object attribute table at a particular remote database at a user computer site containing the most current data corresponding to the particular object identifier;

communicating a get message to the particular remote database including the particular object identifier;

at the particular remote database, consulting an object attribute table index to obtain retrieval information corresponding to the particular object identifier in the object attribute table;

retrieving object attributes associated with the particular object identifier from the object attribute table;

communicating retrieved object attributes to the object broker computer;

at the object broker computer, updating the retrieved object attributes with the one or more object attributes to be updated, to obtain updated object attributes associated with the particular object attribute;

communicating the updated object attributes to the updating user computer for storage in the associated remote database.

15. The method of claim 14, further comprising the step of updating the mapping table and object index tables at the object broker computer to reflect that the updating user computer now has the most current information associated with the particular object identifier.

16. The method of claim 14, wherein the updating user computer is the same as the particular remote database containing the most current data corresponding to the particular object identifier.

17. The method of claim 14, wherein the remote database at the updating user computer did previously contain object attributes associated with the particular object identifier in an object attribute table, and further comprising the step of updating selected updated object attributes in the object attribute table associated with the particular object identifier.

18. The method of claim 14, wherein the updating user computer is at a different user site as the particular remote database containing the most current data corresponding to the particular object identifier.

19. The method of claim 18, wherein the remote database at the updating user computer did not previously contain any object attributes associated with the particular object identifier, and further comprising the step of adding the updated object attributes to an object attribute table associated with the updating user computer in association with the particular object identifier.

20. The method of claim 1, wherein the mapping table stores information relating object identifiers, status information, and location information.

21. The method of claim 20, wherein the user computers are located at a user computer site including at least one customer database and at least one remote database associated therewith, and wherein the location information relates to a data communications location for a remote database that stores data items in association with object identifiers.

22. The method of claim 21, wherein data items comprise at least one object attribute stored in at least one object attribute table maintained in the at least one remote database, and wherein the location information comprises information identifying at least one object attribute table in at least one remote database.

23. The method of claim 22, wherein the status information comprises date information identifying which one of a possible pluralities of occurrences of a selected object identifier is the most current.

24. The method of claim 1, wherein each of the user computers are located at a user computer site including at least one customer database and at least one remote database associated therewith.

25. The method of claim 24, wherein at least one customer database is a heterogeneous database structure relative to at least one other computer system in the distributed system, and wherein the at least one remote database is homogeneous relative to the object broker computer.

26. The method of claim 24, wherein the at least one customer database runs on a different computer system than a computer system that runs the at least one remote database.

27. The method of claim 24, wherein the at least one customer database runs on the same computer system as the at least one remote database.

28. The method of claim 24, wherein at least one user computer in the distributed data processing system includes a customer database of a first database structure, and at least one other user computer in the distributed data processing system includes a customer database of a second database structure different from the first database structure so that such database structures are heterogeneous.

29. The method of claim 24, wherein the remote database associated with each user computer site is operative for performing the steps of creating a new object instance, storing data items in association with the object identifier, and retrieving data stored at the remote user computer associated with an object identifier provided by the object broker computer.

30. The method of claim 29, wherein the remote database is further operative for communicating location information and related object identifiers to the object broker computer via the data communications network.

31. The method of claim 24, wherein the step of storing the data items associated with the subject at the user computer in association with the object identifier comprises the steps of:

importing data items from a customer database into an associated remote database as selected data attributes associated with a particular object identifier, and

communicating the particular object identifier to the object broker computer.

32. The method of claim 31, wherein the step of communicating the particular object identifier to the object broker computer includes communicating predetermined search terms associated with the selected data attributes to the object broker computer.

33. The method of claim 32, further comprising the step of storing the predetermined search terms in an object attribute index stored at the object broker computer, the object attribute index relating object identifiers and search terms, and storing location information and status information indicative of the source and status of the object attributes and the object identifier in the mapping table.

34. The method of claim 31, wherein the step of importing data items from the customer database comprises the steps of:

importing a first set of data items from the customer database as object attributes associated with a first object identifier;

determining that the first object identifier is related to at least one additional second object identifier; and

importing a second set of data items from the customer database as object attributes associated with the second object identifier.

35. The method of claim 34, wherein the steps of importing comprise importing object attributes associated with the second object identifier that are in a dependent relationship to object attributes associated with the first object identifier in a predetermined order so as to preserve dependency relationships.

36. The method of claim 34, further comprising the steps of:

storing object attributes associated with the first object identifier in a first object attribute table;

storing the first object identifier and the second object identifier in a junction table relating object identifiers to each other;

storing object attributes associated with the second object identifier in a second object attribute table;

in response to a determination that the storing of object attributes for the second object identifier calls for information corresponding to the first object identifier, storing the, first object identifier in a corresponding field in the second object attribute table,

whereby reference to the second object identifier causes referral to the first object identifier for selected object attributes.

37. The method of claim 24, wherein each remote database at each user computer site comprises a homogeneous data structure, and further comprising the step of importing selected data items from an associated customer database into the remote database.

38. The method of claim 37, wherein the step of importing selected data items from an associated customer database into the remote database comprises the step of mapping data items in a heterogeneous data structure on a customer database into predetermined object attributes stored in the associated remote database.

39. The method of claim 38, wherein the step of importing occurs in response to a put request message provided by a user at a user computer site.

40. The method of claim 38, wherein the step of importing comprises entering data items from the heterogeneous data structure into an object attribute table maintained at the associated remote database.

41. The method of claim 40, further comprising the step of maintaining an object attribute table index at the remote database to allow rapid searching for particular object attributes stored in an object attribute table in the respective remote database.

42. The method of claim 41, wherein the object attribute table index comprises a table relating an object identifier to one or more data items associated with the object identifier.

43. A method of operating a distributed data processing system including a plurality of independent remotely located user computers that process user data in user databases,

the user computers being interconnected for data communications by data communication hardware over a data communication network,

the user computers being operative to perform data operations of storing, updating, and retrieving user data items in response to user commands, comprising the steps of:

(a) providing a location service storing information relating object identifiers and location information associated with subsets of data items stored in the plurality of user computers;

(b) associating a first object identifier with a selected first set of user data items relating to a first logical object;

(c) associating a second object identifier with a selected second set of user data items relating to a second logical object;

(d) associating a third object identifier with a third set of user data items relating to a third logical object, the third set of user data items including particular data items corresponding to the first logical object and the second logical object;

(e) in response to a selected search term relating to the third logical object originating at one of the user computers, searching an object index relating search terms to the object identifiers to obtain the third object identifier;

(f) consulting the location service based on the third object identifier to obtain the related first object identifier and second object identifier;

(g) determining selected locations of a user computer storing data items associated with the first object identifier and a user computer storing data items associated with the second object identifier;

(h) retrieving data items associated with the first object identifier and the second object identifier from the selected user computers; and

(i) joining the retrieved selected data items associated with the first object identifier and the second object identifier to obtain a complete set of data items associated with the third object identifier.

44. The method of claim 43, wherein the distributed data processing system includes at least one central computer operative for providing the location service, the object index, and issuing requests to user computers to retrieve data items corresponding to object identifiers.

45. The method of claim 43, wherein each of the remotely located user computers comprises a heterogeneous data structure.

46. The method of claim 43, wherein each of the remotely located user computers are located at a user site including at least one customer database and at least one remote database associated therewith, wherein said at least one customer database is a heterogeneous database structure relative to at least one other computer system in the distributed system.

47. A method of operating a distributed data processing system including a plurality of independent remotely located user computers that process user data in user databases and at least one object broker computer,

the user computers being interconnected with the object broker computer by data communication hardware over a data communication network,

the user computers being located at a user computer site including at least one customer database and at least one remote database associated therewith,

the user computers being operative to perform data operations of storing, updating, and retrieving user data items in response to user commands, comprising the steps of:

(a) for a subject at one of the user computers for which data is to be processed in the system, creating an object instance by assigning a unique object identifier to data items associated with the subject;

(b) storing the data items associated with the subject at the user computer in association with the object identifier by;

(b1) importing data items from a customer database into an associated remote database as selected data attributes associated with a particular object identifier by;

(b1a) importing a first set of data items from the customer database as object attributes associated with a first object identifier;

(b1b) determining that the first object identifier is related to at least one additional second object identifier; and

(b1c) importing a second set of data items from the customer database as object attributes associated with the second object identifier; and

(b2) communicating the particular object identifier to the object broker computer;

(c) at the object broker computer, storing the locations of the user computers in a mapping table in association with object identifiers;

(d) in response to a query to the object broker computer for data relating to a particular subject in question, retrieving a selected object identifier for the subject in question;

(e) in response to retrieval of an object identifier for the subject in question in the preceding step, retrieving the location of a remote user computer associated with the selected object identifier;

(f) retrieving data stored at the remote user computer associated with the selected object identifier via the data communication network;

(g) storing object attributes associated with the first object identifier in a first object attribute table;

(h) storing the first object identifier and the second object identifier in a junction table relating object identifiers to each other;

(i) storing object attributes associated with the second object identifier in a second object attribute table;

(j) in response to a determination that the storing of object attributes for the second object identifier calls for information corresponding to the first object identifier, storing the first object identifier in a corresponding field in the second object attribute table,

whereby reference to the second object identifier causes referral to the first object identifier for selected object attributes.

48. The method of claim 47, wherein each of the remotely located user computers comprises a heterogeneous data structure, and further comprising the steps of:

at the user computers, mapping predetermined data items stored in the user computers to corresponding object attributes associated with a predetermined instance of an object;

storing the object attributes in an object attribute table in the remote user computers in association with object identifiers.

49. The method of claim 47, wherein at least one customer database is a heterogeneous database structure relative to at least one other computer system in the distributed system, and wherein the at least one remote database is homogeneous relative to the object broker computer.

50. The method of claim 47, wherein the at least one customer database runs on a different computer system than a computer system that runs the at least one remote database.

51. The method of claim 47, wherein the at least one customer database runs on the same computer system as the at least one remote database.

52. The method of claim 47, wherein the user computers are located at a user computer site including at least one customer database and at least one remote database associated therewith, the at least one remote database storing an object attribute table for relating object attributes to object identifiers, and wherein the object broker computer stores an object index table for relating at least one predetermined search term to at least one object identifier.

53. The method of claim 52, further comprising the steps of:

in response to an add request at one of the user computers to add a subject to the system, providing selected data items associated with the subject to be added from the customer database to the remote database;

at the remote database, carrying out the step of creating new object instance by assigning a new object identifier to data items associated with the subject;

communicating information relating the new object identifier to at least one corresponding search term to the object broker computer;

at the object broker computer, updating the object index table to reflect the association of the new object identifier, the corresponding search term;

at the object broker computer, updating the mapping table to reflect the location of the user computer that added the new object instance identified by the new object identifier.

54. The method of claim 52, further comprising the steps of:

in response to a get request at a requesting one of the user computers based on a particular object identifier, communicating the particular object identifier to the object broker computer;

at the object broker computer, consulting the mapping table based on the particular object identifier to identify a particular remote database at a particular user computer site;

communicating a get message to the particular remote database at the particular user computer site including the particular object identifier;

at the particular remote database, consulting an object attribute table index to obtain retrieval information corresponding to the particular object identifier in the particular object attribute table;

retrieving object attributes associated with the particular object identifier from the particular object attribute table; and

communicating retrieved object attributes to the object broker computer and thence to the requesting user computer.

55. The method of claim 52, further comprising the steps of:

in response to a get all request at a requesting one of the user computers based on a particular object identifier that is related to one or more related object identifiers, communicating the particular object identifier to the object broker computer;

at the object broker computer, consulting an object index table that relates object identifiers of a first type to object identifiers of a second type to retrieve one or more related object identifiers associated with the particular object identifier;

at the object broker computer, consulting the mapping table based on retrieved related object identifiers to identify a one or more object attribute tables at one or more particular remote databases at one or more user computer sites containing data on the related object identifiers;

communicating a get message to the one or more remote databases including the related object identifiers;

at the one or more particular remote databases, consulting one or more object attribute table indexes to obtain retrieval information corresponding to the related object identifiers in the one or more object attribute tables;

retrieving object attributes associated with the related object identifiers from the one or more object attribute tables; and

communicating retrieved object attributes to the object broker computer and thence to the requesting user computer.

56. The method of claim 52, further comprising the steps of:

in response to an update request at an updating one of the user computers based on a particular object identifier for which one or more object attributes are to be updated, communicating the particular object identifier to the object broker computer together with the one or more object attributes to be updated;

at the object broker computer, consulting the mapping table based the particular object identifier to identify an object attribute table at a particular remote database at a user computer site containing the most current data corresponding to the particular object identifier;

communicating a get message to the particular remote database including the particular object identifier;

at the particular remote database, consulting an object attribute table index to obtain retrieval information corresponding to the particular object identifier in the object attribute table;

retrieving object attributes associated with the particular object identifier from the object attribute table;

communicating retrieved object attributes to the object broker computer;

at the object broker computer, updating the retrieved object attributes with the one or more object attributes to be updated, to obtain updated object attributes associated with the particular object attribute;

communicating the updated object attributes to the updating user computer for storage in the associated remote database.

57. A method of operating a distributed data processing system including a plurality of independent remotely located user computers that process user data in user databases and at least one object broker computer,

the user computers being interconnected with the object broker computer by data communication hardware over a data communication network,

the user computers being operative to perform data operations of storing, updating, and retrieving user data items in response to user commands, comprising the steps of:

(a) for a subject at one of the user computers for which data is to be processed in the system, creating an object instance by assigning a unique object identifier to data items associated with the subject;

(b) storing the data items associated with the subject at the user computer in association with the object identifier;

(c) at the object broker computer, storing the locations of the user computers in a mapping table in association with object identifiers;

(d) in response to a query to the object broker computer for data relating to a particular subject in question, retrieving a selected object identifier for the subject in question;

(e) in response to retrieval of an object identifier for the subject in question in the preceding step, retrieving the location of a remote user computer associated with the selected object identifier;

(f) retrieving data stored at the remote user computer associated with the selected object identifier via the data communication network;

(g) maintaining an object index table at the object broker computer for relating at least one predetermined search term to at least one object identifier, wherein the object index table for relating at least one predetermined search term to at least one object identifier is a relational data base table; and

(h) maintaining a junction index table relating object identifiers corresponding to a first class of objects to object identifiers corresponding to a second class of objects.

58. The method of claim 57, wherein each of the remotely located user computers comprises a heterogeneous data structure, and further comprising the steps of:

at the user computers, mapping predetermined data items stored in the user computers to corresponding object attributes associated with a predetermined instance of an object;

storing the object attributes in an object attribute table in the remote user computers in association with object identifiers.

59. The method of claim 57, wherein the mapping table stores information relating object identifiers, status information, and location information.

60. The method of claim 57, wherein the query to the object broker originates at a first user computer, and the data associated with the selected object identifier is stored at a second user computer, and further comprising the step of communicating data retrieved, associated with the selected object identifier, to the object broker and then to the first user computer via the data communication network.

61. The method of claim 57, wherein the data items associated with the subject stored at the user computer in association with the object identifier are stored in an object attribute table.

62. The method of claim 61, wherein the remotely located user computers include at least one customer database and at least one remote database associated therewith, and wherein the object attribute table is stored in the remote database.

63. The method of claim 57, wherein the step of assigning a unique object identifier to data items associated with a subject comprises the steps of:

providing a global object identification address space corresponding to a range of object identifiers for association with a plurality of subjects;

allocating a predetermined range of object identifiers within the global object identification address space to each remotely located user computer.

64. The method of claim 63, wherein the step of allocating a predetermined range of object identifiers is carried out at the object broker computer, and wherein a new object instance is created by assigning a unique object identifier from a predetermined range of object identifiers is carried out at the user computers.

65. The method of claim 57, wherein the user computers are located at a user computer site including at least one customer database and at least one remote database associated therewith, the at least one remote database storing an object attribute table for relating object attributes to object identifiers, and wherein the object broker computer stores an object index table for relating at least one predetermined search term to at least one object identifier.

66. The method of claim 65, further comprising the steps of:

in response to an add request at one of the user computers to add a subject to the system, providing selected data items associated with the subject to be added from the customer database to the remote database;

at the remote database, carrying out the step of creating new object instance by assigning a new object identifier to data items associated with the subject;

communicating information relating the new object identifier to at least one corresponding search term to the object broker computer;

at the object broker computer, updating the object index table to reflect the association of the new object identifier, the corresponding search term;

at the object broker computer, updating the mapping table to reflect the location of the user computer that added the new object instance identified by the new object identifier.

67. The method of claim 65, further comprising the steps of:

in response to a search request at a querying one of the user computers to determine whether an object exists corresponding to a selected search term, communicating the selected search term to the object broker computer;

at the object broker computer, consulting the object index table to determine whether there is an object identifier associated with the selected search term;

in response to a determination that there is an object identifier associated with the selected search term, retrieving the corresponding object identifier;

providing a message to the querying user computer via the data communication network including the corresponding object identifier.

68. The method of claim 65, further comprising the steps of:

in response to a get request at a requesting one of the user computers based on a particular object identifier, communicating the particular object identifier to the object broker computer;

at the object broker computer, consulting the mapping table based on the particular object identifier to identify a particular remote database at a particular user computer site;

communicating a get message to the particular remote database at the particular user computer site including the particular object identifier;

at the particular remote database, consulting an object attribute table index to obtain retrieval information corresponding to the particular object identifier in the particular object attribute table;

retrieving object attributes associated with the particular object identifier from the particular object attribute table; and

communicating retrieved object attributes to the object broker computer and thence to the requesting user computer.

69. The method of claim 65, further comprising the steps of:

in response to a get all request at a requesting one of the user computers based on a particular object identifier that is related to one or more related object identifiers, communicating the particular object identifier to the object broker computer;

at the object broker computer, consulting an object index table that relates object identifiers of a first type to object identifiers of a second type to retrieve one or more related object identifiers associated with the particular object identifier;

at the object broker computer, consulting the mapping table based on retrieved related object identifiers to identify a one or more object attribute tables at one or more particular remote databases at one or more user computer sites containing data on the related object identifiers;

communicating a get message to the one or more remote databases including the related object identifiers;

at the one or more particular remote databases, consulting one or more object attribute table indexes to obtain retrieval information corresponding to the related object identifiers in the one or more object attribute tables;

retrieving object attributes associated with the related object identifiers from the one or more object attribute tables; and

communicating retrieved object attributes to the object broker computer and thence to the requesting user computer.

70. The method of claim 65, further comprising the steps of:

in response to an update request at an updating one of the user computers based on a particular object identifier for which one or more object attributes are to be updated, communicating the particular object identifier to the object broker computer together with the one or more object attributes to be updated;

at the object broker computer, consulting the mapping table based the particular object identifier to identify an object attribute table at a particular remote database at a user computer site containing the most current data corresponding to the particular object identifier;

communicating a get message to the particular remote database including the particular object identifier;

at the particular remote database, consulting an object attribute table index to obtain retrieval information corresponding to the particular object identifier in the object attribute table;

retrieving object attributes associated with the particular object identifier from the object attribute table;

communicating retrieved object attributes to the object broker computer;

at the object broker computer, updating the retrieved object attributes with the one or more object attributes to be updated, to obtain updated object attributes associated with the particular object attribute;

communicating the updated object attributes to the updating user computer for storage in the associated remote database.

71. The method of claim 57, wherein each of the user computers are located at a user computer site including at least one customer database and at least one remote database associated therewith.

72. The method of claim 71, wherein at least one customer database is a heterogeneous database structure relative to at least one other computer system in the distributed system, and wherein the at least one remote database is homogeneous relative to the object broker computer.

73. The method of claim 71, wherein the at least one customer database runs on a different computer system than a computer system that runs the at least one remote database.

74. The method of claim 71, wherein the at least one customer database runs on the same computer system as the at least one remote database.

75. The method of claim 71, wherein the remote database associated with each user computer site is operative for performing the steps of creating a new object instance, storing data items in association with the object identifier, and retrieving data stored at the remote user computer associated with an object identifier provided by the object broker computer.

76. The method of claim 71, wherein the step of storing the data items associated with the subject at the user computer in association with the object identifier comprises the steps of:

importing data items from a customer database into an associated remote database as selected data attributes associated with a particular object identifier, and

communicating the particular object identifier to the object broker computer.

77. The method of claim 76, wherein the step of communicating the particular object identifier to the object broker computer includes communicating predetermined search terms associated with the selected data attributes to the object broker computer.

78. The method of claim 77, further comprising the step of storing the predetermined search terms in an object attribute index stored at the object broker computer, the object attribute index relating object identifiers and search terms, and storing location information and status information indicative of the source and status of the object attributes and the object identifier in the mapping table.

79. The method of claim 76, wherein the step of importing data items from the customer database comprises the steps of:

importing a first set of data items from the customer database as object attributes associated with a first object identifier;

determining that the first object identifier is related to at least one additional second object identifier; and

importing a second set of data items from the customer database as object attributes associated with the second object identifier.

80. The method of claim 79, further comprising the steps of:

storing object attributes associated with the first object identifier in a first object attribute table;

storing the first object identifier and the second object identifier in a junction table relating object identifiers to each other;

storing object attributes associated with the second object identifier in a second object attribute table;

in response to a determination that the storing of object attributes for the second object identifier calls for information corresponding to the first object identifier, storing the first object identifier in a corresponding field in the second object attribute table,

whereby reference to the second object identifier causes referral to the first object identifier for selected object attributes.

81. The method of claim 71, wherein at least one user computer in the distributed data processing system includes a customer database of a first database structure, and at least one other user computer in the distributed data processing system includes a customer database of a second database structure different from the first database structure so that such database structures are heterogeneous.

82. The method of claim 81, wherein each remote database at each user computer site comprises a homogeneous data structure, and further comprising the step of importing selected data items from an associated customer database into the remote database.

83. The method of claim 82, wherein the step of importing selected data items from an associated customer database into the remote database comprises the step of mapping data items in a heterogeneous data structure on a customer database into predetermined object attributes stored in the associated remote database.

84. The method of claim 83, wherein the step of importing occurs in response to a put request message provided by a user at a user computer site.

85. The method of claim 83, wherein the step of importing comprises entering data items from the heterogeneous data structure into an object attribute table maintained at the associated remote database.