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TTable Update

Posted on 2004-08-24
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Last Modified: 2010-04-05
Hi,

I am struggling with a real easy concept. Any help please.

I am using a TTable component to insert a blob into an Oracle database. the insert works fine, but when I want to update the table, I get a unique constraint error as the table want to insert another record with the same unique key,. instead of updating the BLOB of the existing key. I am not sure how to perform the update.

Teh database table only consist of two columns, one for a primary key and one for the blob.

My code are as follows:

with dm.tblBLOB do
  begin
    dm.Maximo.StartTransaction;
    Open;
    if blobexist = 'Y' then Insert else Update;

    FieldByName('DOCUMENT').AsString := docid;
    TBlobField(FieldByName('CPLANT_BLOB')).LoadFromFile(file2blobname);
    Post;
    dm.Maximo.Commit;

0
Comment
Question by:barnarp
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3 Comments
 
LVL 27

Expert Comment

by:kretzschmar
ID: 11879292
??

>>if blobexist = 'Y' then Insert else Update;

should be

if blobexist = 'Y' then Update else insert;
or
if blobexist = 'Y' then Insert else Edit;
or
if blobexist = 'Y' then Edit else Insert;

   

   
   
0
 
LVL 17

Accepted Solution

by:
Wim ten Brink earned 200 total points
ID: 11881117
> if blobexist = 'Y' then Insert else Update;
Why insert mode if you're going to modify an existing record? Use just Edit...

with dm.tblBLOB do
  begin
    dm.Maximo.StartTransaction;
    Open;
    Edit;
    FieldByName('DOCUMENT').AsString := docid;
    TBlobField(FieldByName('CPLANT_BLOB')).LoadFromFile(file2blobname);
    Post;
    dm.Maximo.Commit;

Then again, this code would always modify the first record that's available after opening the table. You might want to navigate to the correct record first with e.g. a locate command. If you can't locate it, then you need to insert the record. Locate it based upon the DOCUMENT key only, btw.
0
 
LVL 17

Expert Comment

by:Wim ten Brink
ID: 11881141
with dm.tblBLOB do
  begin
    dm.Maximo.StartTransaction;
    Open;
    if Locate('DOCUMENT', VarArrayOf([docid]), []) then Edit else Insert;
    FieldByName('DOCUMENT').AsString := docid;
    TBlobField(FieldByName('CPLANT_BLOB')).LoadFromFile(file2blobname);
    Post;
    dm.Maximo.Commit;

That's the code with locate. Didn't test it, though...
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