Help! How to determine the actual data size in a BLOB field (long raw)

Hi,

In one of the tables of my database there is a BLOB field, say image_file, in which I save various image files.

I have implemented the database and its client software by using MS SQL server 6.5 and RDO 2.0, in which before I get the image file from image_file filed,
I'm using "SELECT DATALENGTH(image_file) ..." to create a resultset and get the actual size of the image file, then get the image by GetChunk() method. It works OK.

Now, I need to change the database into an Oracle DB, and still use RDO for connection. As in Oracle's PL/SQL there is no DATALENGTH( ) function, my question is: is there a relevant function like DATALENGTH in PL/SQL?

BTW, I have tried VSIZE( ), unfortunately, it can't be used on a LONG type field, and LENGTH( ), LENGTHB( ) are not for such usage. I also know if I use
Oracle's oo4o, Ican solve the problem easily. But at present I don't want to migrate my code from RDO to oo4o.

Please help me and thanks in advance.

I posted this message to other newgroup aboout Oracle, but got no response yet. I apologize for my cross-posting, but I urgently need an answer as I have
no any documetation on Oracle at hand.

Huiqun Zhou Received on Fri Oct 02 1998 - 22:24:13 CDT