On-the-fly format conversion
Techniques are provided for accessing data stored in a database. According to one technique, a request is received from an application for a stored file that is currently stored in a database. The stored file is associated with a first file type. One or more database commands are issued to retrieve data associated with the stored file from the database. A renderer is selected from a plurality of renderers based on a first set of selection criteria. The renderer is used to generate an outbound file from the data. The outbound file corresponds to a second file type. The outbound file is provided to the application.
1. A method for accessing data stored in a database, the method comprising:
receiving a request, from an application to an operating system, for a stored file that is currently stored in a database, said stored file being associated with a first file type,
in response to receiving the request for the stored file that is currently stored in the database, the operating system issuing a command to a translation engine;
in response to receiving the command from the operating system, the translation engine issuing one or more database commands to retrieve data associated with said stored file from said database;
selecting a renderer from a plurality of renderers based on a first set of selection criteria;
using said renderer to generate an outbound file from said data, wherein said outbound file corresponds to a second file type,
wherein said first file type is different than said second file type; and
providing said outbound file to said application.
2. The method of claim 1 further wherein:
the method further includes the step of determining that the application supports a plurality of file types; and
said renderer selects said second file type from said plurality of file types based on a second set of selection criteria.
3. The method of claim 2 wherein:
the method further includes the step of determining values of one or more attributes of said stored file; and
said second set of selection criteria includes a selection criterion that is based on the values of said one or more attributes.
4. The method of claim 2 wherein the step of determining that the application supports a plurality of file types includes the steps of:
determining an identity of said application; and
reading data from said database that indicates capabilities of said application.
5. The method of claim 1 wherein the first set of selection criteria includes a selection criterion that is based on the file type of said stored file.
6. The method of claim 1 wherein:
the step of generating said outbound file includes combining into a single file values from a plurality of columns of one or more tables in said database.
7. The method of claim 1 further comprising performing the following steps before receiving said request:
receiving an original file of said first data type;
parsing said original file to generate one or more metadata values for said original file;
storing said original file in said database as said stored file; and
storing said one or more metadata values in said database in a manner that associates said one or more metadata values with said stored file.
8. The method of claim 7 wherein:
the step of receiving said original file is performed by receiving data transmitted according to a first protocol;
the step of providing said outbound file to said application is performed by transmitting data according to a second protocol;
said first protocol being different from said second protocol.
9. The method of claim 8 wherein:
the first protocol is an I/O protocol supported by a first operating system; and
the second protocol is an I/O protocol supported by a second operating system.
10. The method of claim 8 wherein at least one of said first protocol and said second protocol belongs to a set of protocols that consists of HTTP, FTP, IMAP4 and POP3.
11. A computer-readable medium bearing instructions for accessing data stored in a database, the computer-readable medium comprising instructions for performing:
receiving a request, from an application to an operating system, for a stored file that is currently stored in a database, said stored file being associated with a first file type;
in response to receiving the request for the stored file that is currently stored in the database, the operating system issuing a command to a translation engine;
in response to receiving the command from the operating system, the translation engine issuing one or more database commands to retrieve data associated with said stored file from said database;
selecting a renderer from a plurality of renderers based on a first set of selection criteria;
using said renderer to generate an outbound file from said data, wherein said outbound file corresponds to a second file type,
wherein said first file type is different than said second file type; and
providing said outbound file to said application.
12. The computer-readable medium of claim 11 further wherein:
the computer-readable medium further includes instructions for performing the step of determining that the application supports a plurality of file types; and
said renderer selects said second file type from said plurality of file types based on a second set of selection criteria.
13. The computer-readable medium of claim 12 wherein:
the computer-readable medium further includes instructions for performing the step of determining values of one or more attributes of said stored file; and
said second set of selection criteria includes a selection criterion that is based on the values of said one or more attributes.
14. The computer-readable medium of claim 12 wherein the step of determining that the application supports a plurality of file types includes the steps of:
determining an identity of said application; and
reading data from said database that indicates capabilities of said application.
15. The computer-readable medium of claim 11 wherein the first set of selection criteria includes a selection criterion that is based on the file type of said stored file.
16. The computer-readable medium of claim 11 wherein:
the step of generating said outbound file includes combining into a single file values from a plurality of columns of one or more tables in said database.
17. The computer-readable medium of claim 11 further comprising instructions for performing the following steps before receiving said request:
receiving an original file of said first data type;
parsing said original file to generate one or more metadata values for said original file;
storing said original file in said database as said stored file; and
storing said one or more metadata values in said database in a manner that associates said one or more metadata values with said stored file.
18. The computer-readable medium of claim 17 wherein:
the step of receiving said original file is performed by receiving data transmitted according to a first protocol;
the step of providing said outbound file to said application is performed by transmitting data according to a second protocol;
said first protocol being different from said second protocol.
19. The computer-readable medium of claim 18 wherein:
the first protocol is an I/O protocol supported by a first operating system; and
the second protocol is an I/O protocol supported by a second operating system.
20. The computer-readable medium of claim 18 wherein at least one of said first protocol and said second protocol belongs to a set of protocols that consists of HTTP, FTP, IMAP4 and POP3.