I wonder why it could be useful for bfile datatype

Question

may be i do know understand exactly,
i always wonder, why we need a bfile for storage?
we also can store the path/filename as a string in any char datatype, so as to get the feaures of bfile more easily, then why oracle make up a datatype as bfile.
what is its special advantages?
thanks for your tips
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Answer 1

Hi,
Following is a very brief explanation of the BFILE data type. See the Oracle8i documentation for more information. Oracle8i Application Developer's Guide - Large Objects (LOBs) can be found at: http://otn.oracle.com/docs/products/oracle8i/doc_library/817_doc/appdev.817/a76940/toc.htm
The BFILE data type is one of the Oracle data types used to access Large OBjects or LOBs. A BFILE is an external LOB type (that is to say, the data is stored externally to the database), while BLOBs and CLOBs are internal LOB types (that is to say, the data is stored internally in the database). All the LOB types share a common API, with the methods such as open and close, read and write (write support for internal LOBs only), and others such as methods to get the LOB length. The LOB interface is the only way to access LOB data from within the database, whether the data is stored internally, as BLOBs or CLOBs, or externally, as BFILEs. (Actually, it is possible to access files on the database server using Java Stored Procedures in the database, given the right access permissions. But that's a different story and doesn't have anything to do with LOBs as such.)
An application can choose whether to store a 'reference' to an external LOB as a BFILE, or as a database directory name plus the file name. If the reference is stored as a BFILE, then the application can access the LOB data directly. If the reference is stored as a database directory name plus file name, then, before accessing the LOB data, the application must first create a BFILE LOB locator using the BFILENAME SQL function.
To sum up:
1) The Oracle BFILE LOB data type is used to specify a LOB locator using which applications access the LOB data.
2) Do applications have to use the BFILE data type to reference external LOB data? No, an application can store the database directory name plus the file name, and create a BFILE data type only when the application needs to read the LOB data.
Hope that helps,
Simon
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