Method and system for implementing and accessing a virtual table on data from a central server

• US 9,081,836 B2
• Filed: 06/28/2004
• Issued: 07/14/2015
• Est. Priority Date: 06/28/2004
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Kolli, Ashish, Wong, Daniel ManHung
• Primary Examiner(s): Perveen, Rehana
• Assistant Examiner(s): Hoffler, Raheem
• Application Number:
  US10/879,266
• Publication Number:
  US 20050289174A1
• Time in Patent Office: 4,033 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 16/256 in federated or virtual databases

Abstract

A method, mechanism, and computer program product for managing, referencing, and accessing centrally managed information are disclosed. Transparency is provided to the centrally managed data by introducing a mapping system between locally expected data and the central data repository. This allows, for example, local relational database systems to transparently access information from a central LDAP directory.

Claims

1. A method for accessing a virtual table, in which the virtual table corresponds to data that is centrally stored at a central storage location, comprising:

receiving a command with a format compliant with a schema for the virtual table at a database, wherein the schema for the virtual table comprises rows and columns;

mapping the command to a converted command, wherein the converted command has a command format appropriate for the central storage location, wherein the act of mapping is performed using a processor; and

issuing the converted command to the central storage location to access the data from the central storage location underlying the virtual table;

wherein the data is stored in the central storage location independent of the schema for the virtual table.

2. The method of claim 1 in which the command is a query.

3. The method of claim 2 further comprising:

obtaining a first result set in a first form corresponding to the central storage location;

mapping the first result to a second result in form corresponding to a local node; and

returning the second result.

4. The method of claim 2 in which the query comprises a SQL query.

5. The method of claim 3 further comprising:

converting from an LDAP semantic for the first result to a relational semantic for the second result.

6. The method of claim 5 in which the second result corresponds to intermediate data that operated upon by the query.

7. The method of claim 6 in which a join operation is performed upon the intermediate data.

8. The method of claim 1 in which the command comprises an update command.

9. The method of claim 8 in which the data is updated at the central storage location.

10. The method of claim 8 in which the command is mapped to LDAP semantics.

11. The method of claim 10 in which a mapping route is used to identify a portion of an LDAP directory to access to perform the update command.

12. The method of claim 10 in which a hint or pragma is used to select a profile or attribute for the update.

13. The method of claim 8 in which transactional semantics are preserved.

14. The method of claim 13 in which a transactional identifier is used, wherein a commit does not occur for the command until the transaction identifier is appropriately returned to the local node.

15. A computer program product comprising a computer usable medium having executable code to execute a process for accessing a virtual table, in which the virtual table corresponds to data that is centrally stored at a central storage location, the process comprising:

receiving a command with a format compliant with a schema for the virtual table at a database, wherein the schema for the virtual table comprises rows and columns;

mapping the command to a converted command, wherein the converted command has a command format appropriate for the central storage location; and

issuing the converted command to the central storage location to access the data from the central storage location underlying the virtual table;

wherein the is stored in the central storage location independent of the schema for the virtual table.

16. The computer program product of claim 15, wherein the process further comprises:

obtaining a first result set in a first form corresponding to the central storage location;

mapping the first result to a second result in form corresponding to a local node; and

returning the second result.

17. The computer program product of claim 15, wherein the process further comprises:

converting from an LDAP semantic for the first result to a relational semantic for the second result.

18. The computer program product of claim 15 in which the second result corresponds to intermediate data that operated upon by the query.

19. A computer-implemented system for accessing a virtual table, in which the virtual table corresponds to data that is centrally stored at a central storage location, comprising:

means for receiving a command with a format compliant with a schema for the virtual table at a database, wherein the schema for the virtual table comprises rows and columns;

means for mapping the command to a converted command, wherein the converted command has a command format appropriate for the central storage location, wherein the means for mapping comprises a processor, and wherein the data is stored in the central storage location independent of the schema for the virtual table; and

means for issuing the converted command to the central storage location to access the data from the central storage location underlying the virtual table.

20. The system of claim 19 further comprising:

means for obtaining a first result set in a first form corresponding to the central storage location;

means for mapping the first result to a second result in form corresponding to a local node; and

means for returning the second result.

21. The system of claim 19 further comprising:

means for converting from an LDAP semantic for the first result to a relational semantic for the second result.

22. The system of claim 19 in which the second result corresponds to intermediate data that operated upon by the query.

23. A method involving use of a virtual table at a local node, the virtual table corresponding to data that is centrally stored at a central storage location independent of a schema for the virtual table, comprising:

receiving at the local node a command with a format that is compliant with the schema for the virtual table, wherein the schema for the virtual table comprises rows and columns;

in response to the received command, determining a converted command using a processor based at least in part on a mapping between the schema for the virtual table at the local node and a structure for the data that is centrally stored at the central storage location; and

issuing the converted command to the central storage location to access the data.

24. The method of claim 23 in which the schema is based upon query criteria.

25. The method of claim 23 in which the schema is based upon a number, type, and parameters of the columns for DB table.

26. The method of claim 23 in which the data is stored in the LDAP protocol and the central storage location comprises a LDAP directory.

27. The method of claim 23 in which the data is mapped to multiple virtual tables.

28. The method of claim 27 in which the multiple virtual tables correspond to different schemas.

29. The method of claim 23 in which the virtual table corresponds to a view.

30. The method of claim 23 in which the data comprises enterprise-wide metadata.

31. The method of claim 30 in which the metadata comprises user information, services information, or organizational information.

32. The method of claim 23, further comprising determining a caching characteristic for the virtual table at the local node.

33. The method of claim 32 in which the caching characteristics is determined by default.

34. The method of claim 32 in which the caching characteristics corresponds to no caching.

35. The method of claim 32 in which the caching characteristics corresponds to persistence of some or all of the data at the local node.

36. The method of claim 35 in which an index is formed against the data that is persisted at the local node.

37. A computer program product comprising a volatile or non-volatile computer usable medium having executable code to execute a process that involves use of a virtual table at a local node, the virtual table corresponding to data that is centrally stored at a central storage location independent of a schema for the virtual table, the process comprising:

receiving at the local node a command with a format that is compliant with the schema for the virtual table, wherein the schema for the virtual table comprises rows and columns;

in response to the received command, determining a converted command using a processor based at least in part on a mapping between the schema for the virtual table at the local node and a structure for the data that is centrally stored at the central storage location; and

issuing the converted command to the central storage location to access the data.

38. The computer program product of claim 37 in which the data is stored in the LDAP protocol and the central storage location comprises a LDAP directory.

39. The computer program product of claim 37 in which the virtual table corresponds to a view.

40. The computer program product of claim 37, wherein the process further comprises determining a caching characteristic for the virtual table at the local node.

41. The computer program product of claim 38 in which the caching characteristics corresponds to persistence of some or all of the data at the local node.

42. A system for executing a process that involves use of a virtual table at a local node, the virtual table corresponding to data that is centrally stored at a central storage location independent of a schema for the virtual table, the system comprising:

means for receiving at the local node a command with a format that is compliant with the schema for the virtual table, wherein the schema for the virtual table comprises rows and columns;

a processor for, in response to the received command, determining a converted command based at least in part on a mapping between the schema for the virtual table at the local node and a structure for the data that is centrally stored at the central storage location; and

means for issuing the converted command to the central storage location to access the data.

43. The system of claim 42 in which the data is stored in LDAP protocol and the central storage location comprises a LDAP directory.

44. The system of claim 42 in which the virtual table corresponds to a view.

45. The system of claim 42, further comprising means for determining a caching characteristic for the virtual table at the local node.

46. The system of claim 45 in which the caching characteristics corresponds to persistence of some or all of the data at the local node.