Re: Code Optimization, PostgreSQL BLOBs (Cheat Method)

Frank D. Engel, Jr. Tue, 12 Oct 2004 11:32:00 -0700

I tried that before and for some reason it did not seem to work. However, at least one other app will need to access the data, and I seriously doubt that app will like the idea of the images being base64 encoded, so that idea will not work anyway.

I'm thinking about maybe translating the functions into Pascal or C and encapsulating them into an external, if I can figure out how to do it. Maybe...

On Oct 12, 2004, at 2:19 PM, Jan Schenkel wrote:

--- "Frank D. Engel, Jr." <[EMAIL PROTECTED]> wrote:

After some research and "playing," I've *finally*
found a way to get
info into and out of PostgreSQL BYTEA BLOBs through
RevDB, but it is
painfully slow.  I wrote the following functions:

function dbBLOB bdat
   put "'" into x
   repeat for each char c in bdat
     put format("\\\\%03o", charToNum(c)) after x
   end repeat

   return x & "'::bytea"
end dbBLOB

function dbUNBLOB adat
   put empty into x
   put 0 into y
   put 0 into n
   put false into esc
   repeat for each char c in adat
     if esc then
       if c is "\" then
         put "\" after x
         put false into esc
       else
         put (8 * y) + c into y
         add 1 to n
         if n is 3 then
           put numToChar(y) after x
           put 0 into y
           put 0 into n
           put false into esc
         end if
       end if
     else if c is "\" then put true into esc
     else put c after x
   end repeat

   return x
end dbUNBLOB


dbBLOB encodes binary data stored in strings (such
as the text property
of an image) into a BYTEA literal which can be used
in an INSERT or
UPDATE statement:

on mouseUp
   revExecuteSQL the database of this stack, "INSERT
INTO table1 VALUES
(" & dbBLOB(image "Image 1") & ")"
end mouseUp


dbUNBLOB decodes binary data returned from the
server back into a
string:

on mouseUp
   put revQueryDatabase(the database of this stack,
"SELECT * FROM
table1") into q
   if q is an integer then
     if revNumberOfRecords(q) > 0 then
       put dbUNBLOB(revDatabaseColumnNumbered(q, 1))
into image "Image 1"
     else answer "No Records"
     revCloseCursor q
   else answer q titled "Error"
end mouseUp


Perhaps the functions will help someone else in a
similar situation;
also, if anyone can find a way to speed these up, I
would certainly
appreciate it...

Frank D. Engel, Jr.


Hi Frank,

If no other applications needs to access the data, you
could just store a Base64 copy of the image data in a
field of type text.

A bit late now, I know...

Jan Schenkel.

===== "As we grow older, we grow both wiser and more foolish at the same time." (La Rochefoucauld)


            
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Re: Code Optimization, PostgreSQL BLOBs (Cheat Method)

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