I have just started using Delphi 3.0 Client/Server version.
I am converting an existing database application to Delphi and SQL.

I have a TQuery object and am retrieving field values using the following
syntax;

string_variable := QueryObject ['field_name'];

where QueryObject is the name of my TQuery object which has a  record
active.

The problem is when the field value is null the system throws an exception.

I can go: try .... except end;
but I would have to do this several thousand times over the course of the
application and it looks messy.

Is there a way to avoid this, should I use variant data types to handle
nulls and the true string values or should I modify the Delphi libraries to
stop throwing exceptions (is this possible?).

So, either use persistent field objects (using fields editor at
desing-time) or, if the program works on volatile/unrecognized data
structures, use QueryObject.Fields[i].AsXXX format. From the above
example, it seems that you know the underlying data types, it's possible
to use any of the above:

string_variable := QueryObjectField_Name.AsString;
or
string_variable := QueryObject .FieldByName('field_name').AsString;

This will eliminate the null values problem.