My application using Oracle 11g as backend. We have a multiple BLOB Columns in Different tables. We are using these columns to store files such as .Doc,.excel,etc. First question is whether storing as BLOB supports Full-text search?
My second question is whether keeping a single table for storing all BLOB data and create a single text index that can be used to search the documents? Is it will be better than keep it in different table columns and separate full-text search indexes? If I keep all the files in a single table shall I exculde the group of rows from Full text search?
Yes, you can store your documents in BLOB columns and then index them with Oracle Text (see manual).
And I’m not sure if multiple BLOB columns are supported (multiple text columns are fine though, I’ve used it myself).
It might be more difficult to have a single text index over different tables. This could be the answer to your second question that you in fact need to merge all documents into a single table.
When using Oracle Text, it seems as if the text index is just an additional index on your table. However, the text index consists of several additional tables that Oracle creates automatically. You cannot change that.