replying to my own message -
update should my myString2 - that is not an actual
error, just copied and pasted it wrong. also i noticed
a problem with i in my final for loop. i changed it to
j since i was being incremented. i still get the same
output however. just to clarify.
--- C S <[EMAIL PROTECTED]> wrote:
> Igor,
>
> thanks for all your help too man. here is what is
> in
> the table images so far when i do a select. its 3
> blobs:
>
> sqlite> select imageID, hex(imageData) from Images;
> 1|00 0003 0006 0009 000C 000F 0012 0015 0018 001B 00
> 2|00 0001 0002 0003 0004 0005 0006 0007 0008 0009 00
> 3|00 0001 0002 0003 0004 0005 0006 0007 0008 0009 00
>
*****************************************************
>
> here is what i have now:
>
> const unsigned short *image;
> int i = 0;
>
> myString2 = "select imageID, imageData from Images";
>
> int status = sqlite3_prepare_v2(db, update.c_str(),
> -1, &statement, NULL);
>
> while ((status = sqlite3_step(statement)) ==
> SQLITE_ROW)
> {
> i++
>
> if(i == 1)
> std::cout << "first row" << std::endl;
>
> else std::cout << "another row" << std::endl;
>
> num_bytes = sqlite3_column_bytes(statement, i);
> num_bytes = num_bytes / sizeof(unsigned short);
> image = new unsigned short[num_bytes];
> image = (const unsigned
> short*)sqlite3_column_blob(statement, i);
>
> for(int i = 0; i < num_bytes; i++)
> std::cout << "image " << i << ": " <<
> image[i]
> << std::endl;
>
> //delete [] image; //causes a crash so far.
> }
>
> status = sqlite3_finalize(statement);
> if (status != SQLITE_OK)
> std::cerr << "Error deleting prepared SQL
> statement" << std::endl;
>
> else std::cout << "finalized statement
> successfully"
> << std::endl;
>
> ***********************************************
>
> Output:
>
> first row
> image 0: 0
> image 1: 3
> image 2: 6
> image 3: 9
> image 4: 12
> image 5: 15
> image 6: 18
> image 7: 21
> image 8: 24
> image 9: 27
> another row
> another row
> finalized statement successfully
>
> --so for some reason i get the first
> blob(successfully, yes!) but it never increments
> after
> that. the statement is also finalized successfully.
> any reason why the other two blobs are not printing
> out?
>
> as a side note i commented out the deleting of the
> image because i got a major abort crash, no doubt
> memory leaks/forbidden access issues.
>
> thanks!!
>
>
>
>
>
>
> --- Igor Tandetnik <[EMAIL PROTECTED]> wrote:
>
> > C S <[EMAIL PROTECTED]> wrote:
> > > thanks for the tip on the hex. now i can see my
> > > entry of the blob. my original loop to fill the
> > > dynamic array with unsigned shorts was this:
> > >
> > > imageArray = new unsigned short[10];
> > >
> > > for(int i = 0; i < 10; i++)
> > > imageArray[i] = i;
> > >
> > > so now if i run the program then do a:
> > >
> > > select imageID, hex(imageData) from Images;
> > >
> > > i get the result:
> > >
> > > 1|0000010002000300040005000600070008000900
> > >
> > > i am not sure where the first 2 leading zeros
> are
> > > coming from
> >
> > The first value (the one at index 0) in imageArray
> > is zero, represented
> > by two zero bytes.
> >
> > > now i need to be able to extract the data back
> out
> > of
> > > the blob with sqlite3_column_blob and
> > > sqlite3_column_bytes so that i can repopulate an
> > > unsigned short array.
> > >
> > > if i have multiple blobs in the table Images how
> > would
> > > i go about retrieving back all this information?
> >
> > You prepare a select statement, e.g.
> >
> > select imageID, imageData from Images;
> >
> > Then you loop over all rows in the resultset with
> > sqlite3_step call
> > (each call advances to the next row), and for each
> > row call
> > sqlite3_column_* once for each column you are
> > interested in.
> >
> > Igor Tandetnik
> >
> >
> >
> > _______________________________________________
> > sqlite-users mailing list
> > [email protected]
> >
>
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
> >
>
>
>
>
>
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