2
TField . - , TQuery - , , , . , .
Delphi , , .
, , , .
.
, . :
- TTable - , , abl;
- TQuery - ( ), SELECT.
FieldByName TTable TQuery:
function FieldByName(const FieldName: string): TField;
Fields [Index], TField.
, , ,
r, rt property DefaultFields: Boolean;
r (read only) , ; rt (run time) , . . . True , ; False , .
, TField Delphi. , Name TField, .
, TField, : (.. Name TTable TQuery, ) , (TTable) (TQuery).
, FIO, Students, , StudentsFIO.
TField, (, " .."), FIO . TField, , , , TField , , :
|
|
StudentsFIO. Index:= 5; // StudentsFIO. Readonly:= True; //
, StudentsFIO TField , FIO , , , .. , . Value, AsBoolean, AsString .. :
IF StudentsFIO.AsString = '' then....
, StudentsFIO TField , FIO , , , .. , . Value, AsBoolean, AsString .. :
IF StudentsFIO.AsString = '' then....
Fields Fields[N].AsString. a , . TField:
property AsBoolean
property AsFloat
property AsInteger
property AsString
property AsDateTime
( ), Delphi . , Delphi Boolean Integer Float, Integer String. String Integer, Float Integer. Date DateTime, AsString AsFloat .
, :
property FieldValues|const FieldName: string]: Variant;
, FieldName, : Tablel.FieldValues['FIO']:= '';
FieldCount . , Fields :
var
S: String;
begin
S:= Fields[0].FieldName;
end;
Fields ( ), , .. - , , .
, FieldByName :
TField
, TField, :
1. ( TTable TQuery);
2. ;
3. Field Editor ( };
4. Add Fields',
5. (TTable) , (TQuery), . Ok. TField.
6. - , , , .