[DUG] Creating fields at runtime

[Alister Christie]

For those interested in a solution:

   q := TQuery.Create(Nil);
   try
     q.DatabaseName := 'Rezy';
     q.SQL.Add('Select Surname, Tit_Init, Greeting, StNo, Street, Add2, 
Add3, Ph1, Ph1Type, Ph2, Ph2Type, Ph3, Ph3Type, Fax, Price, Bedrooms, 
email, LookingFor');
     q.SQL.Add('from contact where status = ''A''');
     q.Name := 'Contact';
     q.Open;  //fill fielddefs
     q.Close;
     for i := 0 to pred(q.FieldDefs.Count) do
       q.FieldDefs[i].CreateField(q);
     strfield := TStringField.Create(q);
     strfield.FieldKind := fkCalculated;
     strfield.FieldName := 'RequirementsDesc';
     strfield.Size := 200;
     strfield.DataSet := q;


     q.OnCalcFields := qContactCalcField;
     q.Open;

....

Open and Close needs to be called to fill the fielddefs property.  This 
is probably similar to what the IDE does to add fields in the fields 
editor.  I hope someone else finds this useful.


Alister Christie
Computers for People
Ph: 04 471 1849 Fax: 04 471 1266
http://www.salespartner.co.nz
PO Box 13085
Johnsonville
Wellington


Alister Christie wrote:
> No it's created at runtime:
> 
>   q := TQuery.Create(Nil);
>     q.DatabaseName := 'Rezy';
>     q.SQL.Add('Select Surname, Tit_Init, Greeting, StNo, Street, Add2, 
> Add3, Ph1, Ph1Type, Ph2, Ph2Type, Ph3, Ph3Type, Fax, Price, Bedrooms, 
> email');
>     q.SQL.Add('from contact where status = ''A''');
>     q.Name := 'Contact';
> //    q.OnCalcFields := qContactCalcField;
> //    strfield := TStringField.Create(q);
> //    strfield.FieldName := 'RequirementsDesc';
> //    strfield.FieldKind := fkCalculated;
> //    strfield.DataSet := q;
>     q.Open;
> 
> The commented out bit creates the calculated field which obscures the 
> other fields once created.  I want to be able to add all the other 
> fields to the q.Fields property, but not have to write the code to add 
> each field individually.
> 
> Any Suggestions?
> 
> Alister Christie
> Computers for People
> Ph: 04 471 1849 Fax: 04 471 1266
> http://www.salespartner.co.nz
> PO Box 13085
> Johnsonville
> Wellington
> 
> Todd Martin wrote:
> 
>> Are your existing fields in the dataset create at design time?
>>
>> ----- Original Message ----- From: "Alister Christie" 
>> <alister at salespartner.co.nz>
>> To: "NZ Borland Developers Group - Delphi List" <delphi at ns3.123.co.nz>
>> Sent: Tuesday, May 31, 2005 1:29 PM
>> Subject: [DUG] Creating fields at runtime
>>
>>
>>> I'm creating a TQuery (descriptively called q) at runtime with a with 
>>> a query such as "select * from contact".  However I want to add a 
>>> calculated field to this using the following code
>>>     strfield := TStringField.Create(q);
>>>     strfield.FieldName := 'RequirementsDesc';
>>>     strfield.FieldKind := fkCalculated;
>>>     strfield.DataSet := q;
>>> However, by adding a calculated field I hide all the fields in the 
>>> fielddefs.  Does anyone know of a way around this, either by putting 
>>> the calculated field in q.fielddefs or adding all the fields to 
>>> q.fields in some easy fashion
>>>
>>>
>>> -- 
>>> Alister Christie
>>> Computers for People
>>> Ph: 04 471 1849 Fax: 04 471 1266
>>> http://www.salespartner.co.nz
>>> PO Box 13085
>>> Johnsonville
>>> Wellington
>>> _______________________________________________
>>> Delphi mailing list
>>> Delphi at ns3.123.co.nz
>>> http://ns3.123.co.nz/mailman/listinfo/delphi
>>>
>>>
>>
>>
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