Query->Post() does not work - why?

[Minotaurus007]

Migrating directly from microOLAP to MyDAC I found that Post() isn't working anymore. I guess some properties have to be switched. But which?

Code: Select all

    Query->First();
    for( int i = 0; i RecordCount; i++, Query->Next() ) {
       Query->Edit();
       Query->FieldValues["Flag"] = true;
       //Query->FieldByName("Flag")->AsBoolean = true;
       //Query->FieldValues["nWDH"] = 7;
       Query->Post();
    }
    Query->Close();

No(!) variables are actually posted, as verified with Navicat.
It is not a boolean problem and another field (nWDH) also does not work (outcommented above).
What am I missing???

[eduardosic]

Migrating directly from microOLAP to MyDAC I found that Post() isn't working anymore. I guess some properties have to be switched. But which?

Code: Select all

    Query->First();
    for( int i = 0; i RecordCount; i++, Query->Next() ) {
       Query->Edit();
       Query->FieldValues["Flag"] = true;
       //Query->FieldByName("Flag")->AsBoolean = true;
       //Query->FieldValues["nWDH"] = 7;
       Query->Post();
    }
    Query->Close();

No(!) variables are actually posted, as verified with Navicat.
It is not a boolean problem and another field (nWDH) also does not work (outcommented above).
What am I missing???

Any Exception Message?
What the value of Query.SQL property?
What Version of MyDAC and C++ Builder?
What Version of MySQL?
The Table Have a Primary key? See DDL of Table

[Minotaurus007]

Any Exception Message?

None.

What the value of Query.SQL property?

Empty.

What Version of MyDAC and C++ Builder?
What Version of MySQL?

mydac555cb6pro
C++Builder 6
MySQL 4.0.13

The Table Have a Primary key? See DDL of Table

Yes, called "ID" in my case.

Meanwhile I managed to Post() by switching the queries' CachedUpdate to OFF. I do not understand why it works now, but it works. However, another problem is being persistent: I still cannot Post() the "nWDH" field:

Code: Select all

Query->First();
    for( int i = 0; i RecordCount; i++, Query->Next() ) {
       Query->Edit();
       Query->FieldValues["Flag"] = true;
       Query->FieldValues["nWDH"] = 7; // doesn't work, remains zero "0".
       Query->FieldValues["nWDH"] = Query->FieldValues["nWDH"] + 7; 
          // doesn't work either, remains zero "0".
       Query->Post();
    }
Query->Close(); 

What's going wrong?!

[eduardosic]

Hi, you need open the table..

In Delphi

Code: Select all

  Query.Close;
  Query.SQL.Text := 'Select * from TableName';
  Query.Execute;
  Query.First;
  While not Query.Eof do begin
    Query.Edit;
    Query.FieldValues["Flag"] = true;
    Query.FieldValues["nWDH"] = 7; // doesn't work, remains zero "0".
    Query.FieldValues["nWDH"] = Query.FieldValues["nWDH"] + 7;
    Query.Post;
    Query.Next;
  end;
    
  Query.Close; 

[Minotaurus007]

Of course, the table(query) was open. But meanwhile I found the strange and surprising solution:

I formerly had set the field "nWDH" to unsigned int. The microOLAP-package tolerated this obviously. Setting this back to int solved the problem immediately for MyDAC. Now Post() updates this field like it should. Perhaps I could have also used a cast like:

Code: Select all

Query->FieldValues["nWDH"] = (unsigned int) 7;

Don't know if it is a bug or a feature in MyDAC. Anyway,

thx again from Germany!
-Mino

[eduardosic]

Of course, the table(query) was open. But meanwhile I found the strange and surprising solution:

I formerly had set the field "nWDH" to unsigned int. The microOLAP-package tolerated this obviously. Setting this back to int solved the problem immediately for MyDAC. Now Post() updates this field like it should. Perhaps I could have also used a cast like:

Code: Select all

Query->FieldValues["nWDH"] = (unsigned int) 7;

Don't know if it is a bug or a feature in MyDAC. Anyway,

thx again from Germany!
-Mino

Hi, i don't know C++ Builder Only Delphi...

i go to test Query.FieldValues["nWDH"] := 7; in Delphi..

i use Query.FieldByName( 'xx' ).AsInteger := 7;

please wait the Dimon goes to answer of correct form.

[Dimon]

I formerly had set the field "nWDH" to unsigned int. The microOLAP-package tolerated this obviously. Setting this back to int solved the problem immediately for MyDAC. Now Post() updates this field like it should. Perhaps I could have also used a cast like:

Code: Select all

Query->FieldValues["nWDH"] = (unsigned int) 7;

I could not reproduce the problem. Please specify how you have set the field "nWDH" to unsigned int.

[Minotaurus007]

Hi Dimon,

since the column "nWDH" is a simple counter, I once had set this MySQL(!) column to unsigned int. In my C++-program however, I used int to do those calculations everywhere. The old software tolerated this, MyDAC doesn't. To keep things simple, I changed the MySQL column to int. Now everything is working fine.

And no, I did not yet a test with unsigned int, because there are way too many occurences in my C++code and I don't want to rewrite the whole thing.

-Mino

[Dimon]

The problem appears because there is created TLargeInt field for MySQL unsigned int field. In Delphi and in C++Builder this field type does not assign value via the Value property.
In order to solve this problem you should use the following code:

Code: Select all

Query->FieldByName("nWDH")->AsInteger = 7;