Re: storing graphics in oracle
Date: 1996/11/03
Message-ID: <327bfa96.2186333_at_dcsun4>#1/1
On Fri, 25 Oct 96 10:59:22 GMT, johne_at_parallax.co.uk (John Eccleston) wrote:
>In article <326D05BB.1D85_at_intelsat.int>, Rohit Saran <rohit.saran_at_intelsat.int> wrote:
>>If one stores a bit-mapped graphics in Oracle, how does one retrieve
>>it.. Can it be done using SQL or some other techniques have to be used.
>>Any pointers will be appreciated.
>>
>>Thanks/Rohit...
>
>Hi,
>
>Be aware that PL/SQL allows a maximum 32K to be read for a LONG column.
>It gives errors when attempting to read LONG columns containing more data
>than this.
>
>Pro*C can be used to insert and select from LONG columns however I think
>it must be done as one block. It would be really nice if you could read
>the LONG column in chunks (like reading a file).
>
>Regards
>
>John
>
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>
With any version of 7.x you can piecewise fetch using OCI (can be mixed with pro*c easily). With 7.3 you can piecewise insert and update in OCI as well. Pro*c, not being an API but declaritive, doesn't lend itself to piecewise fetching as OCI does.
With 7.3, you can piecewise fetch using pl/sql. the following example is a subroutine I use that takes an open cursor, assumes the first column is a long, fetches it 4k at a time and prints it out.
This works with raws as well...
procedure showlong( p_cursor in integer ) as
l_cursor integer default p_cursor;
l_n number;
l_long_val varchar2(4096);
l_long_len number;
l_buflen number := 4096;
l_curpos number := 0;
begin
dbms_sql.define_column_long(l_cursor, 1); l_n := dbms_sql.execute(l_cursor);
htp.preOpen;
if (dbms_sql.fetch_rows(l_cursor)>0)
then
loop
dbms_sql.column_value_long(l_cursor, 1, l_buflen, l_curpos ,
l_long_val, l_long_len );
l_curpos := l_curpos + l_buflen;
htp.ps( l_long_val );
exit when l_long_len = 0;
end loop;
end if;
htp.preClose;
dbms_sql.close_cursor(l_cursor);
exception
when others then
if dbms_sql.is_open(l_cursor) then
dbms_sql.close_cursor(l_cursor);
end if;
htp.preClose;
raise;
end showlong;
Thomas Kyte
Oracle Government
tkyte_at_us.oracle.com
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statements and opinions are mine and do not necessarily reflect the opinions of Oracle Corporation Received on Sun Nov 03 1996 - 00:00:00 CET