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 7,284,010 B2
• Filed: 10/23/2003
• Issued: 10/16/2007
• Est. Priority Date: 10/23/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Raman, Balan Sethu, Yan, Kangrong, Rajan, Rajeev B.
• Primary Examiner(s): Breene; John
• Assistant Examiner(s): Ehichioya; Fred I
• Application Number:
  US10/692,227
• Publication Number:
  US 20050091255A1
• Time in Patent Office: 1,454 Days
• Field of Search: 707 1- 10, 707/100, 707/101, 707/102, 707/103.R, 707/104.1, 707/206, 707/103.Y, 705/7, 705/34, 705/35, 709/201, 709/203, 709/226, 709/227, 709/229, 715/501.1, 715/530, 715/835, 719/310
• US Class Current: 1/1
• 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

A type of an object that can be persisted in a database store is defined by a user. The type definition comprises fields and behaviors, each field having a respective data type. One or more fields of the type definition may be designated as containing data of a type that is to be stored as a file outside of the database store and separately from the other fields of the type definition. When a request is received to store an object that is an instance of the user defined type, the data in any so designated field of the object is stored in a file outside of the database store, preferably within a file system of the computer on which the database store is implemented. The data in each of the other fields of the object is stored within the database store in the usual manner. The database store maintains a link, or reference, between the persisted object and the data of the field that is stored as a file outside of the database store. Applications are provided “out of band” access, via the file system of the computer, to the file in which the data of given field is stored outside the database store.

Claims

1. In a computer system in which an object that is an instance of a user defined type can be persisted in a database store, wherein a definition of the user defined type comprises a plurality of fields, each of said plurality of fields being assigned any one of a plurality of data types supported by the database store, at least one of said plurality of fields of the definition being designated as containing data that is to be stored as a file outside of the database store separately from the data of the other of said plurality of fields of the type definition while maintaining the assigned data type of said at least one designated field, a method comprising:

creating a unique dedicated directory within a file system of the computer system for storing files containing the data of said at least one designated field of instances of the user defined type;

receiving requests to store objects that are different instances of the user defined type, and for each such request to store an object that is an instance of the user defined type;

determining from the designation of said at least one field of the instance of the user defined type that the data of that field is to be stored as a file outside of the database

storing the data of said at least one designated field of the instance of the user defined type as a respective file within the created directory; and

storing the data in each of the other fields of said plurality of fields of the instance of the user defined type within the database store.

2. The method recited in claim 1, wherein a location of the created directory within the file system of the computer system is based at least in part upon a logical structure of the database store.

3. The method recited in claim 2, wherein the logical structure of the database store comprises one or more tables, and wherein the location of said created directory within the file system is associated with one of said one or more tables.

4. The method recited in claim 2, wherein the logical structure of the database store comprises one or more tables, each comprising one or more columns, and wherein the location of said created directory within the file system is associated with one of said columns.

5. In a computer system in which an object that is an instance of a user defined type can be persisted in a database store, wherein a definition of the user defined type comprises a plurality of fields, each of said plurality of fields being assigned any one of a plurality of data types supported by the database store, at least one of said plurality of fields of the definition being designated as containing data that is to be stored as a file outside of the database store separately from the data of the other of said plurality of fields of the type definition while maintaining the assigned data type of said at least one designated field, a method comprising:

receiving a request to store an object that is an instance of the user defined type;

determining from the designation of said at least one field that the data of that field is to be stored as a file outside of the database store;

storing the data in said at least one designated field of said plurality of fields of the instance of the user defined type as a file outside of the database store;

storing the data in each of the other fields of said plurality of fields of the instance of the user defined type within the database store;

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

determining from the identity of the field of the object within the database store a path within the file system of the computer system to the file containing the data of that field of the object; and

executing the call to open the file using the determined path.

6. The method recited in claim 5, further comprising providing a link between the data of the fields of the object that are stored within the database store and the data of the field that is stored as a file outside of the database store.

7. The method recited in claim 5, wherein the data of the fields of the object that are stored within the database store are stored as fragments within a column of a table of the database, the column having been designated as the user defined type.

8. The method recited in claim 7, wherein a unique identifier associated with the object is stored in another column of the table in a same row as the data of the fields of the object.

9. The method recited in claim 5 wherein the file system of the computer system comprises a Microsoft NTFS file system and wherein the application programming interface to the file system comprises the Win32 application programming interface.

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

11. The method recited in claim 5, further comprising:

performing a database operation on the data of said at least one designated field of the instance of the user-defined type, wherein the database operation is performed on the data of said at least one designated field as if it were stored within the database store.

12. The method recited in claim 11, wherein the database operation may comprise one of an INSERT, UPDATE or DELETE operation.

13. A computer readable storage medium having program code stored thereon for use in a computer system in which an object that is an instance of a user defined type can be persisted in a database store, wherein a definition of the user defined type comprises a plurality of fields, each of said plurality of fields being assigned any one of a plurality of data types supported by the database store, at least one of said plurality of fields of the definition being designated as containing data that is to be stored as a file outside of the database store separately from the data of the other of said plurality of fields of the type definition while maintaining the assigned data type of said at least one designated field, said program code, when executed on a computer system, causing the computer system to:

create a unique dedicated directory within a file system of the computer system for storing files containing the data of said at least one designated field of instances of the user defined type;

receive requests to store objects that are different instances of the user defined type, and for each such request to store an object that is an instance of the user defined type;

determine from the designation of said at least one field that the data of that field is to be stored as a file outside of the database store;

store the data of said at least one designated field of the instance of the user defined type as a respective file within the created directory; and

store the data in each of the other fields of said plurality of fields of the instance of the user defined type within the database store.

14. The computer-readable storage medium recited in claim 13, wherein a location of the created directory within the file system of the computer system is based at least in part upon a logical structure of the database store.

15. The computer-readable storage medium recited in claim 14, wherein the logical structure of the database store comprises one or more tables, and wherein the location of said created directory within the file system is associated with one of said one or more tables.

16. The computer-readable storage medium recited in claim 14, wherein the logical structure of the database store comprises one or more tables, each comprising one or more columns, and wherein the location of said created directory within the file system is associated with one of said columns.

17. A computer readable storage medium having program code stored thereon for use in a computer system in which an object that is an instance of a user defined type can be persisted in a database store, wherein a definition of the user defined type comprises a plurality of fields, each of said plurality of fields being assigned any one of a plurality of data types supported by the database store, at least one of said plurality of fields of the definition being designated as containing data that is to be stored as a file outside of the database store separately from the data of the other of said plurality of fields of the type definition while maintaining the assigned data type of said at least one designated field, said program code, when executed on a computer system, causing the computer system to:

receive a request to store an object that is an instance of the user defined type;

determine from the designation of said at least one field that the data of that field is to be stored as a file outside of the database store;

store the data in said at least one designated field of said plurality of fields of the instance of the user defined type as a file outside of the database store;

store the data in each of the other fields of said plurality of fields of the instance of the user defined type within the database store;

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

determining from the identity of the field of the object within the database store a path within the file system of the computer to the file containing the data of that field of the object; and

executing the call to open the file using the determined path.

18. The computer readable storage medium recited in claim 17, wherein the program code further causes the computer system to provide a link between the data of the fields of the object that are stored within the database store and the data of the field that is stored as a file outside of the database store.

19. The computer readable storage medium recited in claim 17, wherein the program code further causes the data of the fields of the object that are stored within the database store to be stored as fragments within a column of a table of the database, the column having been designated as the user defined type.

20. The computer readable storage medium recited in claim 19, wherein the program code further causes the computer system to store a unique identifier associated with the object in another column of the table in a same row as the data of the fields of the object.

21. The computer readable storage medium recited in claim 17 wherein the file system of the computer system comprises a Microsoft NTFS file system and wherein the application programming interface to the file system comprises the Win32 application programming interface.

22. The computer readable storage medium recited in claim 17, wherein the type of the object is defined as a class in managed code.

23. The computer readable storage medium recited in claim 17, wherein the program code further causes the computer system to:

perform a database operation on the data of said at least one designated field of the instance of the user-defined type, wherein the database operation is performed on the data of said at least one designated field as if it were stored within the database store.

24. The computer readable storage medium recited in claim 23, wherein the database operation may comprise one of an INSERT, UPDATE or DELETE operation.