Opaque types

• US 6,470,348 B1
• Filed: 07/31/2000
• Issued: 10/22/2002
• Est. Priority Date: 09/08/1998
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle Corporation
• Inventors: Krishnamurthy, Viswanathan, Govindarajan, Rajagopalan, Nori, Anil
• Primary Examiner(s): Shah, Sanjiv
• Application Number:
  US09/629,541
• Time in Patent Office: 813 Days
• Field of Search: 707/101, 707/102, 707/103, 707/100, 707/104
• US Class Current: 1/1
• CPC Class Codes: G06F 16/289 Object oriented databases
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users

Abstract

A method and apparatus are provided for handling within a database system data items that are associated with data types whose native structure is not known to the database system. The data items are stored within the database system in their native structure, even though it is not understood by the database system. To store the data items, the database system calls a pickling routine that is provided by the user, or by the runtime subsystem of the programming environment that is native to the data item. To retrieve the routine from storage, the database system calls an unpickling routine, also provided by the user or the appropriate runtime subsystem. Because the database maintains the data items in their native format, no conversions are required as the data items are passed between the database system and external routines that manipulate the data items. Techniques are also provided for declaring attributes of the data item that can be accessed within the database system. The user provides routines for the database system to call in order to access the declared attributes, which may be different than the actual attributes that the data item has in its native environment.

Claims

1. A method for handling within a database system a data item that is associated with a data type whose native structure is not known to said database system, the method comprising the steps of:

said database system receiving user input that specifies a set of attributes;

said database system receiving user input that specifies a data type that is supported by said database system for each attribute in said set of attributes;

said database system receiving user input that specifies an external routine for accessing a first attribute of said set of attributes, wherein said external routine expects said data item to have said native structure;

said database system invoking said external routine to access a first attribute; and

in response to invoking said external routine, said database system receiving from said external routine a value that is structured according to the data type associated with said first attribute.

2. The method of claim 1 further comprising the step of maintaining said data item in said native structure as the data item is passed between said database system and routines that expect said data item to be in said native structure.

3. The method of claim 1 wherein said native structure has a plurality of attributes, and said plurality of attributes do not have a one-to-one correspondence with said set of attributes.

4. The method of claim 3 wherein the at least one attribute does not correspond to any of said plurality of attributes.

5. The method of claim 1, wherein:

said external routine is written in a computer language; and

said data type of said first attribute is not a primitive data type defined by the computer language.

6. A computer-readable medium carrying one or more sequences of instructions for handling within a database system a data item that is associated with a data type whose native structure is not known to said database system, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

said database system receiving user input that specifies a set of attributes;

said database system receiving user input that specifies a data type that is supported by said database system for each attribute in said set of attributes;

said database system receiving user input that specifies an external routine for accessing a first attribute of said set of attributes, wherein said external routine expects said data item to have said native structure;

said database system invoking said external routine to access said first attribute; and

in response to invoking said external routine, said database system receiving from said external routine a value that is structured according to the data type associated with said first attribute.

7. The computer-readable medium of claim 6, the steps further comprising the step of maintaining said data item in said native structure as the data item is passed between said database system and routines that expect said data item to be in said native structure.

8. The computer-readable medium of claim 6 wherein said native structure has a plurality of attributes, and said plurality of attributes do not have a one-to-one correspondence with said set of attributes.

9. The computer-readable medium of claim 8 wherein the at least one attribute does not correspond to any of said plurality of attributes.

10. The computer-readable medium of claim 6, wherein:

said external routine is written in a computer language; and

said data type of said first attribute is not a primitive data type defined by the computer language.

11. A database system for processing a data item that is associated with a data type whose native structure is not known to said database system;

said database system configured to receive user input that specifies a set of attributes;

said database system configured to receive user input that specifies a data type that is supported by said database system for each attribute in said set of attributes;

said database system configured to receive user input that specifies an external routine for accessing a first attribute of said set of attributes, wherein said external routine expects said data item to have said native structure;

said database system configured to invoke said external routine to access said first attribute; and

in response to invoking said external routine, said database system configured to receive from said external routine a value that is structured according to the data type associated with said first attribute.

12. The database system of claim 11, further configured to maintain said data item in said native structure as the data item is passed between said database system and routines that expect said data item to be in said native structure.

13. The database system of claim 11, wherein said native structure has a plurality of attributes, and said plurality of attributes do not have a one-to-one correspondence with said set of attributes.

14. The database system of claim 13, wherein the at least one attribute does not correspond to any of said plurality of attributes.

15. The database system of claim 11, wherein:

said external routine is written in a computer language; and

said data type of said first attribute is not a primitive data type defined by the computer language.