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So really happy with connecting to the DB and all that. My Grid object is fine and showing all records etc. Really happy with SQL. And the concept "DBs are all about sets"

My issue is:

I create an ADO query or dataset object where the SQL returns one record only. I know I have done that by interrogating MyFrame.ADOQuery1.RecordCount (it returns 1) But how do I then get access to the record fields simply ?

I want to write

MyRecord[] := MyFrame.ADOQuery1.ReturnRecord; // could be current record as I know there is only one

Questions are : is there/can I create a var type I can use to read that record into ? And how do I do that ? Kinda thought there would be a ADOQuery method that would return a record into an array of the same type (though not sure how to specify that type) (emphasises to show reserved words versus natural english)

Anyway, I have been trying to do this for days and clearly missing something. Help, as ever, appreciated.

AlwaysLearning
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  • [dbGo overview](http://docwiki.embarcadero.com/RADStudio/en/DbGo_Overview) has links to tutorial pages regarding database programming in Delphi. – Ken White Feb 27 '18 at 13:26

1 Answers1

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All Delphi dataset types are descended from TDataSet. This implements a data access model in which the dataset has a logical "cursor" which, if the dataset contains any data rows at all, is positioned on exactly one data row, initially the first one immediately after the dataset is opened. The Fields property of the dataset, or its FieldByName method can be used to access the field values of the data row which the dataset curor is pointing to.

Navigating or traversing the dataset is a simple matter of using one of the dataset's navigation methods (e.g. Next, Prior, MoveBy and Locate). For example

DataSet.First;
while not DataSet.Eof do begin
  Memo1.Lines.Add(DataSet.FieldByName('Country').AsString);
  DataSet.Next;
end;

If you've followed what I've said above, it should be obvious what this code does - if not, ask.

For your "age" example, just do this:

var
  Age : Integer;
[...]
  Age := DataSet.FieldByName('Age').AsInteger;
  • it's as simple as that.

It is generally not a good idea to try to use a record as you seem to be envisaging to store a copy of the current data row's contents. It makes an unnecessary and avoidable copy of the row data.

Equally, using an array to store the current row's data is unnecessary and not really the "Delphi" way of working with dataset rows, it's more like the sort of thing you might (be forced to) do in VB or similar. It has little or no bebifit with Delphi datasets.

Rudy Velthuis
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MartynA
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  • Hi MartynA. thanks for your quick response. I simply want to get to a DB record field e.g. "age" into an integer variable so I can work with it doing a simple check. Oddly, I can do all sorts of DB things but cannot get a simple command that extracts a field value from the record (at the cursor position). Searched hi and lo but cannot get any code that does that. – AlwaysLearning Feb 26 '18 at 22:32
  • I've added an example of retrieving the Age field to an integer variable. – MartynA Feb 26 '18 at 22:42
  • Well, that was on the button. var Age : Integer; [...] Age := DataSet.FieldByName('Age').AsInteger; that's really helpful. – AlwaysLearning Feb 26 '18 at 22:57
  • In that case, please feel free to accept my answer. – MartynA Feb 26 '18 at 22:59
  • MartynA : a most helpful post - very greatful – AlwaysLearning Feb 26 '18 at 23:02
  • In case you're not familiar with it, there is a "tick" icon at the top LHS of the answer. Clicking it marks the answer as accepted. – MartynA Feb 26 '18 at 23:05
  • Not sure how to do this or if it is in the commercial model of stackoverflow but I would send £10 via paypal to you for this answer and happy if stackoverflow got 1 of them for enabling your excellent answer. Anyhow Really appreciated. – AlwaysLearning Feb 26 '18 at 23:26
  • sorry if £10 sounded too little for your expertise. – AlwaysLearning Feb 26 '18 at 23:28
  • @AlwaysLearning: Thanks but that really isn't necessary. Payment isn't part of the SO ethos, and contributors are strictly volunteers operating on an f.o.c. basis. – MartynA Feb 27 '18 at 09:07