Object views for relational data

• US 7,133,880 B1
• Filed: 04/11/2000
• Issued: 11/07/2006
• Est. Priority Date: 10/31/1997
• Status: Expired due to Term

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Hong, Chin, Cheng, Tze-Pin, Wijaya, Joyo, Nori, Anil
• Primary Examiner(s): Colbert, Ella
• Application Number:
  US09/547,191
• Time in Patent Office: 2,401 Days
• Field of Search: 707/1, 707/4, 707/10, 707/102, 707/103, 707/103.R, 707/2, 707/3
• US Class Current: 1/1
• CPC Class Codes: G06F 16/284 Relational databases
• CPC Class Codes: G06F 16/289 Object oriented databases
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99934 Query formulation, input preparation, or translation
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing

Abstract

A method and apparatus for presenting and modifying data from a set of tables in a database is provided. A view that is defined is based on a set of one or more tables that may include relational tables or object tables. The view defines a presentation of data from the one or more tables as a set of objects that reside in the database. Data is read from the one or more rows of the tables based on the view, and is presented as a set of objects that reside in the database. An object id that is based on data from the one or more rows is generated and associated with each object presented. The view may specify which columns from the one or more tables contain values used to generate the object ids. A trigger may associated with the view. The set of objects presented may be presented as objects having an attribute that is a column object. Column objects include user specified object types, collection objects (e.g. nested tables and variable arrays), or references to objects.

Claims

1. A method for presenting data from a set of one or more tables as a set of objects that belong to an object class, the method comprising the steps of:

reading data from one or more rows of the set of one or more tables, wherein said one or more rows do not store an object id used for modeling the data in said one or more rows as an object that belongs to said object class;

reading database metadata that defines how to derive object ids from values in one or more columns;

generating, in the manner defined by said database metadata, an object id derived from one or more values in the one or more columns in said one or more rows; and

presenting data from said one or more rows as an object that belongs to said object class and that has said object id.

2. The method of claim 1, wherein the step of generating a object id includes generating an object id based on values from one or more rows of a relational table that belongs to the set of one or more tables.

3. The method of claim 1, further comprising the step of generating a reference to the object based on the object id.

4. The method of claim 3, further comprising the step of accessing the object based on the reference generated for the object.

5. The method of claim 1, wherein:

the method further includes the steps of;

receiving a request to define a view, said request specifying that said object id is generated based on values in said one or more columns;

in response to receiving the request to define the view, storing specification data that specifies the one or more columns; and

the step of generating an object id includes determining how to generate the object id by inspecting said specification data.

6. The method of claim 5, wherein the step of receiving a request to define a view includes receiving a request that specifies the one or more columns as including at least one column from a relational table.

7. A method for presenting, as an object, data from a set of one or more tables residing in one or more databases, the method comprising the steps of:

reading first database matadata that indicates how to generate a column object from one or more columns;

reading a first set of data from the one or more columns of a plurality of rows from the set of one or more tables, wherein second database metadata defines said one or more tables, wherein said second database metadata does not specify how to generate said column object from said one or more columns;

generating, in the manner indicated by said first database metadata, a particular column object based on said first set of data; and

presenting a second set of data from said set of one or more tables as object oriented data by presenting said second set of data as said object that has said particular column object as an attribute.

8. The method of claim 7, wherein the step of reading a first set of data includes reading data from one or more rows of at least one relational table.

9. The method of claim 7, wherein the step of generating a particular column object includes generating a collection object.

10. The method of claim 9, wherein the step of generating a collection object includes generating said collection object as a list of elements belonging to a single data type.

11. The method of claim 9, wherein the step of generating a collection object includes generating said collection object as a nested table.

12. The method of claim 9, wherein the step of generating a particular column object includes generating a column object belonging to a user specified object type.

13. The method of claim 9, where the step of generating a particular column object includes generating a column object that is a reference to another object.

14. The method of claim 13, wherein the step of generating a particular column object includes generating a column object that is a reference to an object presented by an object view.

15. The method of claim 13, wherein the step of generating a particular column object includes generating a column object that is a reference to an object residing in a database.

16. A computer system, comprising:

a processor;

a memory coupled to said processor;

database metadata that indicates how to derive object ids from values in one or more columns;

a set of one or more tables, said set of one or more tables containing one or more rows, wherein said one or more rows do not store an object id used for modeling the data in said one or more rows as an object that belongs to said object class;

said processor configured to read data from one or more rows of the set of one or more tables;

said processor configured to generate, in the manner defined by said database metadata, an object id derived from one or more values from said one or more rows, wherein said one or more values reside in said one or more columns; and

said processor configured to present data from said one or more rows as an object that belongs to an object class and that has said object id.

17. The computer system of claim 16, wherein said values from said one or more rows include values from one or more rows of a relational table that belongs to said set of one or more tables.

18. The computer system of claim 16, further comprising:

said processor configured to receive a request to define a view, said request specifying one or more columns of the set of one or more tables containing values used to generate said object id;

said processor configured to respond to receiving the request to define the view by storing specification data that specifies the one or more columns; and

said processor configured to generate the object id based on values from said one or more rows by determining how to generate the object id by inspecting said specification data.

19. A computer system, comprising:

a processor;

a memory coupled to said processor;

one or more databases;

a set of one or more tables contained in said one or more databases;

first database metadata that defines how to generate a column object from one or more columns;

second database metadata that defines said one or more tables, wherein said second database metadata does not specify how to generate said column object from said one or more columns;

said processor configured to read a first set of data from a plurality of rows from the set of one or more tables;

said processor configured to generate, in the manner defined by said first database metadata, a particular column object based on said first set of data; and

said processor configured to present a second set of data from said set of one or more tables as object oriented data by presenting said second set of data as said object that has said particular column object as an attribute.

20. A computer-readable medium caring one or more sequences of one or more instructions for presenting data from a set of one or more tables as a set of objects that belong to an object class, wherein the execution of the one or more sequences of the one or more instructions causes the one or more processors to perform the steps of:

reading data from one or more rows of the set of one or more tables, wherein said one or more rows do not store an object id used for modeling the data in said one or more rows as an object that belongs to said object class;

reading database metadata that defines how to derive object ids from values in one or more columns;

generating, in the manner defined by said database metadata, an object id derived from one or more values in the one or more columns in said one or more rows; and

presenting data from said one or more rows as an object that belongs to said object class and that has said object id.

21. The computer readable medium of claim 20, wherein the step of generating an object id includes generating an object id based on values from one or more rows of a relational table that belongs to the set of one or more tables.

22. The computer readable medium of claim 21, wherein:

the one or more sequences of instructions includes one or more instructions for performing the steps of;

receiving a request to define a view, said request specifying one or more columns of the set of one or more tables containing values used to generate said object id;

in response to receiving the request to define the view, storing specification data that specifies the one or more columns; and

the step of generating an object id includes determining how to generate the object id by inspecting said specification data.

23. The computer readable medium of claim 22, wherein the step of receiving a request to define a view includes receiving a request that specifies the one or more columns as including at least one column from a relational table.

24. The computer-readable medium of claim 20, the steps further comprising the step of generating a reference to the object based on the object id.

25. The computer-readable medium of claim 24, wherein the steps further comprise the step of accessing the object based on the reference generated for the object.

26. A computer-readable medium carrying one or more sequences of one or more instructions for presenting, as an object, data from a set of one or more tables residing in one or more databases, wherein the execution of the one or more sequences of the one or more instructions causes the one or more processors to perform the steps of:

reading first database metadata that defines how to generate a column object from one or more columns;

reading a first set of data from the one or more columns of a plurality of rows from the set of one or more tables, wherein second database metadata defines said one or more tables, wherein said second database metadata does not specify how to generate said column object from said one or more columns;

generating, in the manner defined by said first database metadata, a particular column object based on said first set of data; and

presenting a second set of data from said set of one or more tables as object oriented data by presenting said second set of data as said object that has said particular column object as an attribute.

27. The computer-readable medium of claim 26, wherein the step of reading a first set of data includes reading data from one or more rows of at least one relational table.

28. The computer-readable medium of claim 26, wherein the step of generating a particular column object includes generating a collection object.

29. The computer-readable medium of claim 28, wherein the step of generating a collection object includes generating said collection object as a list of elements belonging to a single data type.

30. The computer-readable medium of claim 28, wherein the step of generating a collection object includes generating said collection object as a nested table.

31. The computer-readable medium of claim 28, wherein the step of generating a particular column object includes generating a column object belonging to a user specified object type.

32. The computer-readable medium of claim 28, wherein the step of generating a particular column object includes generating a column object that is a reference to another object.

33. The computer-readable medium of claim 32, wherein the step of generating a particular column object includes generating a column object that is a reference to an object presented by an object view.

34. The computer-readable medium of claim 32, wherein the step of generating a particular column object includes generating a column object that is a reference to an object residing in a database.

35. A method performed by one or more computers, comprising:

storing data in a table of a database that is managed by a database server;

wherein the table is defined by a table definition;

wherein an object class is defined by an object class definition;

maintaining, separate from the table definition and obejct class definition,

metadata that indicates how to derive object ids from values stored in the table; and

the database server deriving, based on the metadata, object ids for objects of the

object class from the values stored in table.

36. The method of claim 35, further comprising the step of generating, based on a particular object id of said object ids, an object reference.

37. The method of claim 36, further including the steps of:

presenting particular data from said table as an object belonging to the object

class and having said particular object id;

said database server executing a database statement that identifies said object

reference; and

wherein execution of said database statement causes the database server to access

said particular data as said object.

38. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 37.

39. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 36.

40. The method of claim 35, wherein said metadata defines an object view which can be referenced in query statements executable by said database server.

41. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 40.

42. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 35.