Easy way to preview BLOB field with SELECT?
Posted on 2002-05-02
Using Oracle 8i, is there any easy way to preview the contents of a BLOB as a field result within a normal select?
For instance, suppose a table t_data has two fields... item_id (integer correlating the data to a real item somewhere) and item_data (the blob). For casual debugging purposes, it would be great to be able to preview the first part of the blob's data in hex dump format. Kind of like:
SELECT (TO_HEXDUMP(item_data, 1000)) from t_data where item_id = 5
and have it print the first 1000 bytes of item_data as:
45 33 39 57 71 36 42 30 0A 0D 4D 51 3C Fake Text..Not
41 6B 52 44 39 3C 41 41 6A 0A 0D 37 30 real values..A
(I made up the hex values).
Obviously something like that would be mostly useless in a program, but it would be really helpful when trying to debug a program to quickly verify whether the right values are being written to the blob in the first place (or find out what values are being read).