Subject Re: [firebird-support] Re: Store Blobs in Seperate Tables?
Author Ann W. Harrison
Lester Caine wrote:
>>Just for the sake of absolute and pedantic correctness, updating (or
>>inserting or deleting) a record doesn't put a "lock" on it.....
> And to complete the picture - since the BLOB is handled in the table as
> a link, all the data in the blob will not be copied until you actually
> make a change to the BLOB itself. That is if my understanding is
> correct. So when handling large volumes of data BLOB's are more
> efficient than VARCHAR fields which would be duplicated on every copy
> even if not changed.
> Is that a fair summary ?
Close but not quite. Remember that the back versions are stored as
differences when practical. If the varchar is unchanged, it doesn't
show up as a difference. If only a few bytes of the varchar change,
only those bytes appear.