SYSTEM AND METHOD FOR STORING AND RETRIEVING A FIELD OF A USER DEFINED TYPE OUTSIDE OF A DATABASE STORE IN WHICH THE TYPE IS DEFINED

• US 20080010285A1
• Filed: 09/26/2007
• Published: 01/10/2008
• Est. Priority Date: 10/23/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Raman, Balan, Rajan, Rajeev, Yan, Kangrong
• Granted Patent: US 7,765,239 B2
• Time in Patent Office: Days
• US Class Current: 707/009
• CPC Class Codes: G06F 16/20 of structured data, e.g. relational data
• CPC Class Codes: G06F 16/289 Object oriented databases
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99934 Query formulation, input preparation, or translation
• CPC Class Codes: Y10S 707/99939 Privileged access
• 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 707/99953 Recoverability

Abstract

In a database system that supports user-defined types, one or more fields of a user-defined type may be designated as containing data that is to be stored as a file outside of a database store, separate from the other fields of the type which are stored within the database. Instead of being stored within the database, the data in such a designated field of an instance of the user-defined type is stored as a file within the file system of a computer. Applications are provided “out of band” access, via the file system of the computer, to the file in which the data of such a field is stored outside the database store. A component of the system intercepts file system open requests and checks security against the database store before allowing the open request to proceed. The component also notifies the database when file system close requests are received.

Claims

1. In a computer system in which an object that is an instance of a user defined type comprising a plurality of fields is persisted in a database, wherein the data of at least one field of the object is stored outside of the database as a file within a file system of the computer system and the other fields of the object are stored within the database, and wherein the file that contains the data of said at least one field can be accessed either via the database or via an application programming interface of the file system, a method comprising:

intercepting a call from an application to the application programming interface of the file system to open the file in which the data of said at least one field of the object is stored, wherein the call identifies the field of the object by its identity within the database;

determining from the database whether the application has permission to access the data of the field of the object identified in said call; and

invoking the application programming interface of the file system to open the file only if the application has permission to do so.

2. The method recited in claim 1, further comprising, prior to invoking the application programming interface of the file system to open the file, determining from the identity of the field of the object within the database a path within the file system of the computer system to the file containing the data of that field of the object.

3. The method recited in claim 1, further comprising:

intercepting a call from the application to the application programming interface of the file system to close the file in which the data of said at least one field of the object is stored;

notifying the database that the call to close the file has been received; and

invoking the application programming interface of the file system to close the file.

4. The method recited in claim 1 wherein the file system of the computer system comprises a Microsoft NTFS file system and wherein the application programming interface of the file system comprises the Win32 application programming interface.

5. The method recited in claim 1, wherein the user defined type of the object is defined as a class in managed code.

6. The method recited in claim 1, further comprising performing a database operation on the data of said at least one field of the object that is stored as a file outside of the database, wherein the database operation is performed on the data of said at least one designated field as if it were stored within the database.

7. The method recited in claim 1, wherein the database operation may comprise one of an INSERT, UPDATE or DELETE operation.

8. A computer-readable storage medium having instructions stored thereon for use in a computer system in which an object that is an instance of a user defined type comprising a plurality of fields is persisted in a database, wherein the data of at least one field of the object is stored outside of the database as a file within a file system of the computer system and the other fields of the object are stored within the database, and wherein the file that contains the data of said at least one field can be accessed either via the database or via an application programming interface of the file system, the instructions, when executed by the computer system, causing the computer system to:

intercept a call from an application to the application programming interface of the file system to open the file in which the data of said at least one field of the object is stored, wherein the call identifies the field of the object by its identity within the database;

determine from the database whether the application has permission to access the data of the field of the object identified in said call; and

invoke the application programming interface of the file system to open the file only if the application has permission to do so.

9. The computer-readable storage medium recited in claim 8, wherein prior to invoking the application programming interface of the file system to open the file, the instructions further cause the computer system to determine from the identity of the field of the object within the database a path within the file system of the computer system to the file containing the data of that field of the object.

10. The computer-readable storage medium recited in claim 8, wherein the instructions further cause the computer to:

intercept a call from the application to the application programming interface of the file system to close the file in which the data of said at least one field of the object is stored;

notify the database that the call to close the file has been received; and

invoke the application programming interface of the file system to close the file.

11. The computer-readable storage medium recited in claim 8, wherein the file system of the computer system comprises a Microsoft NTFS file system and wherein the application programming interface of the file system comprises the Win32 application programming interface.

12. The computer-readable storage medium recited in claim 8, wherein the user defined type of the object is defined as a class in managed code.

13. The computer-readable storage medium recited in claim 8, wherein the instructions further cause the computer system to perform a database operation on the data of said at least one field of the object that is stored as a file outside of the database, wherein the database operation is performed on the data of said at least one designated field as if it were stored within the database.

14. The computer-readable storage medium recited in claim 8, wherein the database operation may comprise one of an INSERT, UPDATE or DELETE operation.

15. A computer system comprising:

a processor;

a file system having an application programming interface;

a database executing on the processor that stores an object that is an instance of a user defined type comprising a plurality of fields, wherein the database stores the data of at least one field of the object outside of the database as a file within the file system of the computer system and stores the other fields of the object within the database, and wherein the file that contains the data of said at least one field can be accessed either via the database or via the application programming interface of the file system;

a component executing on the processor and programmatically interfaced to both the database and the file system, the component operating to (i) intercept a call from an application to the application programming interface of the file system to open the file in which the data of said at least one field of the object is stored, wherein the call identifies the field of the object by its identity within the database, (ii) determine from the database whether the application has permission to access the data of the field of the object identified in said call, and (iii) invoke the application programming interface of the file system to open the file only if the application has permission to do so.

16. The computer system recited in claim 15, wherein prior to invoking the application programming interface of the file system to open the file, said component obtains, based on the identity of the field of the object within the database, a path within the file system of the computer system to the file containing the data of that field of the object.

17. The computer system recited in claim 15, wherein said component further operates to:

intercept a call from the application to the application programming interface of the file system to close the file in which the data of said at least one field of the object is stored;

notify the database that the call to close the file has been received; and

invoke the application programming interface of the file system to close the file.

18. The computer system recited in claim 15, wherein the file system of the computer system comprises a Microsoft NTFS file system and wherein the application programming interface of the file system comprises the Win32 application programming interface.

19. The computer system recited in claim 15, wherein the user defined type of the object is defined as a class in managed code.