Adds new field expression to the dataset.
function AddFieldExpression(const Expression: string; StrictReferences: boolean = False): TFieldExpression; overload;
The method adds new field expression to the dataset. The expression has to be specified in the string format using rules described in the article. The name of the dataset field being created will be set automatically, according to the specified expression. To explicitly specify the name for the resulting field, the overloaded AddFieldExpression method can be used.