. :
a) ;
b) ;
c) .
(a) . Autoinc.
(b) , . 䳿 OnValidate .
(c) , TDataSource .
TDataSource 䳿, :
OnDataChange;
OnStateChange;
OnUpdateData.
OnStateChange , DataSet. , Post, DataSet (dsBrowse). ϳ dsBrowse. , , . , dsBrowse .
1. ?
2. ?
3. Data Set?
4. Data Set ?
5. ?
6. ?
3
: . . Delphi.
: Delphi.
:
1. .
2. .
3. Delphi.
4. .
, , . , , FieldByName.
1:
Studinfo
Edit1.Text:= Studinfo.FieldByName (''). As String
2:
3 6 Edit1 Edit2 Button1.
Procedure TForm1.Button1Click (Sender: TObject)
Begin
ADOTable1.First;
While not (ADOTable1.EOF) do
Begin
ADOTable1.Edit;
ADOTable1.Fields [6]. Asstring:= Edit1.Text;
ADOTable1.Fields [3]. Asstring:= Edit2.Text;
ADOTable1.Post;
ADOTable1.Next;
End;
End
|
|
|
ᑺ Index. 0.
New . : Data, Calculated Lookup.
Data - ;
Calculated - , ;
Lookup - , .
. Calculated OnCalcFields ᑺ ADOTable.
:
, . "".
Procedure TForm1. ADOTable1CalcFields (Data Set: TDataSet);
Var
Cina: float;
Kilk: float;
Begin
Cina:= Table1.FieldByName('ֳ').AsFloat;
Kilk:= Table1.FieldByName('ʳ').AsFloat;
Table1.FieldByName('').AsFloat = cina*kilk;
End;
End.
1. ?
2. ?
3. Delphi.
4. Delphi ?
5. ?
4
: Delphi.
:
1. ᑺ TEdit .
2. .
1. 㳿 ADO
Locate Lookup.
Function Locate (const KeyFields:string; const KeyValues:variant; Options: TLocateOptions): Boolean;
Function Lookup (const KeyFields:string; const KeyValues:variant; const ResultFields: string): Variant;
Locate , ( ) , . . IoCaseInsensitive , IoPartialKey . , True.
ADOTable1.Locate ('Last_Name; First_Name', VarArrayOf (['Edit1.text', 'Edit2.text']), []);
Lookup , , - . , Variant, ResultFields.
ADOTable1.Lookup ('Last_Name; First_Name', VarArrayOf (['Edit1.text', 'Edit2.text']), 'Last_Name;First_Name');
, KeyFields .
., Locate Lookup
:
procedure TForm4.Button2Click(Sender: TObject);
begin
if not
Datamodule2.spojivach. Locate ('ϲ;',VArArray f (['Edit2.text','Edit1.text']),[])
then ShowMessage(' ');
end;
procedure TForm4.Button3Click(Sender:TObject);
|
|
|
begin
DataModule2.spojivach.Lookup('ϲ;'VarArrayOf(['Edit1.text','Edit2.text']),
'ϲ;');
end;
. 8
Գ
Table, . . Filter, Filtered , FilterOptions.
Գ :
- Filter ;
- - OnFilterRecord.
Գ . .
, Filter. : >,<, >=, <=, =, <>, : AND, OR, NOT.
Field1>100 AND Field2=20
.
1. Delphi?
2. Locate Lookup?
3. ?
4. ?
5. Delphi?
6. ?
7. ?
5
: . ³ 볺 .
: SQL ADOQuery.
:
1. ADOQuery, TDataSource, TDBGrid .
2. .
3. .
ᒺ ADOQuery
Delphi Local SQL, . Delphi pass through SQL ( SQL), : Oracle, MS SQL Server, My SQL, Sybase, Interbase, .
SQL LOCALSQL.HLP.
Ha ADOTable, ADOQuery .
