Mike Matrigali wrote:
Suresh Thalamati wrote:
Daniel John Debrunner wrote:
Suresh Thalamati wrote:
BLOB:
....
1) Allow import/export of blob data only when they it is stored
in an external file.
2) Write the blob data to the export file along with other data
types during export, assuming the blob data does not contain any
delimiters and throw an error if on import if it finds delimiters
inside the data, by interpreting it using the same code-set as the
other character data.
I say option 1) and I assume it's for all binary data, not just BLOB,
e.g. VARCHAR FOR BIT DATA etc. Seems like with binary data the chance
of having a problematic character in the text file is close to 100%.
Dan.
Thanks for reading the proposal, Dan. I agree with you , chance of
finding delimiter character inside a binary data is very high. I will
go with the option 1. Your assumption is correct , it applies to all
the binary data.
I also agree, it seems like a reasonable first step to default binary
export/import to external files.
I am probably missing something here though. I thought for char data
there is an algorithm that handles delimiter data within it. Why does
that not work for binary data also? Is it a codeset issue?
Yes. For character data, double delimiters are used if there are
delimiter characters inside the data. i.e say if a column contains
'he said "derby is solid database" ' , then it is written to the
export file as "he said ""derby is a solid database "" " . So on
export of the data, data is modified before writing to the file.
It may be possible to do the same thing by interpreting the binary
data in specified code-set and add an extra delimiter for every
delimiter found on export and do the reverse on import. But unlike
the character data , if the binary data is changed and if user import
it to some other application, the data may mean/look completely
different if the added extra delimiter characters are not removed.
Another thing to note here is in a character data user knows there
might be delimiter characters inside and specify a delimiter character
that is not in the data, if he/she does not want data to modified on
export. Where as with binary data that is not possible at all.
If you think modifying a binary data on export is ok, then it might
be possible to use same concept as character data. My only concern
here is if we export image of a "cat" and add delimiters to it by
interpreting it as character data, it may look like a "tiger" if
extra characters added is not removed :-)
Thanks
-suresh
