update on table buffer is not working after 'buf 2con' 'con2buf'

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Posted on by Matthias Ulbricht

Hello,
I want to convert an buffer into a container and for this I used buf2con() function. Then I use this container for a second buffer with the con2buf() function.
Now I want change some values and write the data back to the database using the update() function. But it is not working. No error message, no exception, just nothing happened. An insert() worked. Any suggestions?

Here is my example

{
    MyTable        buf1;
    MyTable        buf2;
    container      c;
    str 10         keyId = "1";
    ;
    
    buf1.KeyId  = keyId;
    buf1.Text   = "Hello World";
    buf1.insert();

    select * from buf1 where buf1.KeyId == keyId;
    
    c = buf2con(buf1);
    
    con2buf(c, buf2);

    if(buf2)
    {
        buf2.selectForUpdate(true);
        ttsbegin;
        buf2.Text = "Hello! Need Help :)";
        buf2.update();
        ttscommit;
    }

    //reread buf1 but the value of field 'text' is still 'Hello World'
    select * from buf1 where buf1.KeyId == keyId;
    info(buf1.Text);
}

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AX 2012 r3 2,426 on at

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1.You are Updating Buf2.Text

(

buf2.selectForUpdate(true);

ttsbegin;

buf2.Text = "Hello! Need Help :)";

buf2.update();

ttscommit;

)

2.At last you are printing Buf1.Text.

(

select * from buf1 where buf1.KeyId == keyId;

info(buf1.Text);

)

3.you are not again Updating Buf1.Text.

4.With out Updating in Buf1 how can changes get reflected.

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Martin Dráb 237,801 Most Valuable Professional on at

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It shouldn't work, although I would expect an exception at runtime.

You can't update buf2, because you never selected it. Calling selectForUpdate(true) merely says that the next select should be with the "for update" flag, but there is no subsequent select.

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Matthias Ulbricht on at

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Hello,
the requirement is that we have built a website which is managed by AX (via business connector). For this reason we have a state machine in AX which controls the process and serializes the required data. I have extended all required classes with pack and unpack functions. In this way, all table buffers are also packed into a container and written to the database as a session with the rest of the data. If the user then enters a message on the web page, the session in AX is then restored and processed.
This works well except for the update.
And we wanted to avoid reloading all data records from the database again for performance reasons.

After some trial and error I found another solution today. If you call the data () function with the same buffer after con2buf (), the update () works afterwards. I don't know why.

con2buf(c, buf2); buf2.data(buf2);

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Vilmos Kintera 46,149 on at

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You are not using the con2buf correctly, it is an empty buffer. Check the documentation, it has a record return type (Common).

https://msdn.microsoft.com/en-us/library/global.con2buf.aspx

https://blogs.msdn.microsoft.com/axperf/2011/09/07/improvements-on-the-global-methods-buf2con-and-con2buf-in-microsoft-dynamics-ax-2012/

So your line should look like this:

buf2 = con2buf(c);

No second parameter is required to determine the return type, since that is already available in the packed buffer. This way a new record is created.

If you intend to replace the value in just the variable, then you do not need a TTS block and an update, just a value assignment.

If you intend to update the record in the DB too, then your approach again is incorrect, and you must select the buffer from the DB first running a select statement on buf2 based on the unique identifiers, then you could do the whole TTS/update steps.

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Matthias Ulbricht on at

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Hello, Vilmos,

thanks for your hint, but the function con2Buf () has no return value. At least not in AX2009.

static void con2Buf(container c, Common common) { fieldId fieldId; int i; DictTable dictTable; if (common.TableId == conpeek(c,1)) { dictTable = new DictTable(common.TableId); fieldId = dictTable.fieldNext(0); i = 2; while (fieldId) { common.(fieldId) = conpeek(c,i); i++; fieldId = dictTable.fieldNext(fieldId); } } }

In my opinion, the use of con2Buf () was correct.

With the rest you will probably be right and the buffer needs to be reloaded.

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Vilmos Kintera 46,149 on at

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It looks different in AX 2012 indeed, did not know that. You may notice how they use makeRecord to create a new empty buffer.

You may implement your version using that code if you want, like con2buf2012.

static Common con2Buf(container _container, Common _rec = null) { Common thisRec = null; TableId tableId; DictTable dictTable; FieldId fieldId; int i; boolean convert = false; if ( prmisDefault(_rec) ) { tableId = conPeek(_container,1); dictTable = new DictTable(tableId); if (dictTable) { thisRec = dictTable.makeRecord(); convert = true; } } else { thisRec = _rec; } if(Types::Container == typeOf(conPeek(_container, conLen(_container)))) { // delegate to kernel API thisRec.con2buf(_container); } else { // backward compatibility: unpack container packed with previous versions of AX tableId = conPeek(_container,1); dictTable = new DictTable(tableId); if(dictTable) { if (convert || tableName2id(_rec.getInstanceRelationType()) == tableId || _rec.TableId == tableId) { fieldId = dictTable.fieldNext(0, TableScope::IncludeBaseTables); i = 2; while (fieldId) { thisRec.(fieldId) = conPeek(_container,i); i++; fieldId = dictTable.fieldNext(fieldId, TableScope::IncludeBaseTables); } } } } return thisRec; }

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Vilmos Kintera 46,149 on at

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Please kindly mark the answers which you have found to be helpful with the checkbox next to each post, in order to resolve the thread and assist others.

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Matthias Ulbricht on at

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Hello, Vilmos,

also the AX2012 variant of the function con2Buf () does not work as expected. So I think Martin Drab is right and the update () is causing problems because the record was never selected.
As I wrote before, it is only a little bit surprising that after the call

buf2.data(buf2);

the update () worked. But since I didn't find any documentation about what exactly is done by the system in the function data (Common _cursor), I can't judge if there is a problem with the unselected data set or if there is a bug. But it should be usable as a workaround.

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Vilmos Kintera 46,149 on at

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Again, you are trying to update an uninitialized buffer. Calling the data method does the initialization.

You could simply remove your new line with the data assignment, and instead of update, call write() on the buffer. Then place a breakpoint both in the overridden insert and update method, and you will see what we have meant. It will stop the debugger in the insert method, since update operation only works for EXISTING record that is already SELECTED.

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