Restructuretableex example on Manual does not work?

[Enrico]

HI

Nexusdb 2 vers. 2.0803.

On the manual, there is an example "How to restructure a table?".
I made a simplified copy of the code (did not know what the Tablelist was, so I use directly the table name).
Everything seems to go smooth. I get no errors, and when I check the datetime stamp of the table (on disk) I see that it was accessed and somewhat modified.
But the new field is not added!
What am I missing?
In the example of the manual there is a variable NeedRestruct: Boolean;
which is never used. Maybe i should set something to true? but what, where?
Thanks for any help.
This is the code (the database is opened outside the procedure)

procedure restructuretable(nxDatabase1: Tnxdatabase);
var

NewDict, Dict: TnxDataDictionary;
TaskInfo: TnxAbstractTaskInfo;
Completed: Boolean;
TableMapper: TnxTableMapperDescriptor;
TaskStatus: TnxTaskStatus;

begin
Dict := TnxDataDictionary.Create;
TableMapper := TnxTableMapperDescriptor.Create;
try
nxDatabase1.GetDataDictionary('test', '', Dict);
NewDict := TnxDataDictionary.Create;
NewDict.Assign(Dict);
NewDict.fieldsdescriptor.ADDFIELD('NewFieldName',' ',nxtshortstring,10,0,false,nil);
TableMapper.MapAllTablesAndFieldsByName(Dict, NewDict);
nxCheck(nxDatabase1.RestructureTableEx('test', '', Dict, TableMapper, TaskInfo));
try
if Assigned(TaskInfo) then begin
repeat
TaskInfo.GetStatus(Completed, TaskStatus);
if not Completed then begin
Sleep(500)
end;
until Completed;
nxCheck(TaskStatus.tsErrorCode);
end;
finally
if Assigned(TaskInfo) then
TaskInfo.Free;
end;
finally
Dict.Free;
TableMapper.Free;
end;

end;

> nxCheck(nxDatabase1.RestructureTableEx('test', '', Dict,
> TableMapper, TaskInfo));

Pass the *new* dictionary in, not the old.


--
Eivind Bakkestuen [NDD]

[Enrico]

Thanks, Eivind
I will try that tomorrow (it's 1 AM here now).
In the meantime, while waiting for an answer, I tried the code shown below
and it seems to work fine.
Is that code ok? Why do I need to create a new Datadictionary and map the files/fields, if I can do anything using the current table data dictionary and modify it and then use tablerestructureEX passing the "empty" Table mapper (i.e. not mapped, just created)?
Thanks

procedure restructuretable(nxDatabase1: Tnxdatabase; t1:TnxTable);
var

NewDict, Dict: TnxDataDictionary;
TaskInfo: TnxAbstractTaskInfo;
Completed: Boolean;
TableMapper: TnxTableMapperDescriptor;
TaskStatus: TnxTaskStatus;
NeedRestruct: Boolean;
var AR : TnxResult;
begin
Dict := TnxDataDictionary.Create;
TableMapper := TnxTableMapperDescriptor.Create;
try
t1.Open;
dict := tnxDataDictionary.Create;
dict.Assign(t1._Dictionary);
t1.Close;
Dict.fieldsdescriptor.ADDFIELD('ddd','',nxtshortst ring,20,0,false,nil);
nxCheck(nxDatabase1.RestructureTableEx(t1.tablenam e, '', Dict, TableMapper, TaskInfo));
try
if Assigned(TaskInfo) then begin
repeat
TaskInfo.GetStatus(Completed, TaskStatus);
if not Completed then begin
Sleep(500)
end;
until Completed;
nxCheck(TaskStatus.tsErrorCode);
end;
finally
if Assigned(TaskInfo) then
TaskInfo.Free;
end;
finally
Dict.Free;
TableMapper.Free;
end;

end;

[Enrico]

Yes Eivind
Your solution worked.
Is the other version (the one that I posted with only Dict without NewDict)
safe? Why do we need a NewDict and MapAllTablesAndFieldsByName when
apparently the same things can be done making all the changes on Dict and not using MapAllTablesAndFieldsByName at all? Is there a disadvantange or a 'risk' doing it without NewDict and MapAllTablesAndFieldsByName?
Thanks

On Sun, 10 Jun 2012 03:31:29 +1000, Enrico
<Enrico.5dwkfi@nx-forums.nexusdb.com> wrote:

>
>Yes Eivind
>Your solution worked.
>Is the other version (the one that I posted with only Dict without
>NewDict)
>safe? Why do we need a NewDict and MapAllTablesAndFieldsByName when
>apparently the same things can be done making all the changes on Dict
>and not using MapAllTablesAndFieldsByName at all? Is there a
>disadvantange or a 'risk' doing it without NewDict and

This combination is needed when you remove or rename fields
during your restructure process.

Regards from Germany

Franz-Leo Chomse [NexusDB Expert]
franz.leo.chomse@ndx.nexusdb_x.com (please remove "_x" to reply)

Eivind Bakkestuen [NDD] wrote:

> > nxCheck(nxDatabase1.RestructureTableEx('test', '', Dict,
> > TableMapper, TaskInfo));
>
> Pass the new dictionary in, not the old.

This error in the documentation was reported a long time ago, but it is
still present in the documentation for version 3! Download the latest
documentation from the website now and check it yourself.