I trying to create a data-aware component that is a single field , multi-record control , something like TDBLoookupList , but with the KeyField only.
I cannot figure how to iterate through the dataset correctly .
private
FFieldDataLink:TFieldDataLink;
FDataList:Tlist;
if FFieldDataLink.DataSet.Active and (FFieldDataLink.FieldName<>'' ) then
begin
try
FFieldDataLink.DataSet.GetFieldList(FFDataList,FieldDataLink.FieldName);
except
DatabaseErrorFmt(SFieldNotFound, [Self.Name,FFieldDataLink.FieldName]);
end;
end;
the above code snippet should return a list of the fields in the buffer, but it returns only the first record .
thanks
Related
I have tables on my database Tb_barang and Tb_jenis. Tb_jenis the following columns kd_jenis (primary key) and jenis. I use TDBLookupComboBox to show the items from the Tb_jenis table. There are 6 items (Mie, Susu, etc). I want to save item selected as kd_jenis not jenis.
How to I save jenis in table to kd_jenis?
Sample data: Tb_jenis
jenis kd_jenis
Mie J1
Susu J2
Here it the code I've tried.
if (kd.Text='') or (jenis.Text='Pilih') then
ShowMessage('Data Tidak Lengkap, Silakkan Dilengkapi !')
else
begin
with dm.Qbarang do
begin
sql.Clear;
SQL.Add('select * from Tb_barang where kd_barang='+quotedstr(kd.text)+'');
open;
end;
if DM.Qbarang.Recordset.RecordCount > 0 then
ShowMessage('Data Sudah Ada, Silakkan Isi Yang Lain!')
else
begin
try
DM.koneksi.BeginTrans;
with DM.QU do
begin
close;
SQL.Clear;
SQL.Add('insert into Tb_barang values('+QuotedStr(kd.Text)+','
+QuotedStr(jenis.Text)+')');
ExecSQL;
end;
DM.koneksi.CommitTrans;
ShowMessage('Data Berhasil Disimpan');
except
DM.Qbarang.Close;
DM.Qbarang.Open;
FormShow(sender);
end;
end;
end;
As i understand you want to get Key Value of table from DBLookupComboBox.
so in it is 2 important property in DBLookupComboBox ListField and KeyField
if you set them correctly For Example KeyField set as kd_jenis and List Field Set as jenis then you will see Jenis on List and you can access to jenis in DBLookupCombobox.text and also you can access to KeyField (in this case kd_jenis) by DBLookupCombobox.KeyValue
you should fallow this steps.
Put a TADOConnection to your form for connecting to a database.
build connection string for connecting to Database.
add a ADO table to your form.
Set Connection property to AdoConnection1(Default Name Of ADOCOnnection).
On ADOTable open the Table name Property and select One of your database table and then set active property as true.
Add a DataSource to your form and set Dataset Property as ADOTable1(Default Name of ADOTable)
Add DBLookupCombobox to your form and Set ListSource as DataSource1(the default name of datasource)
Open ListField Property and Select witch field do you want to show in Combobox.
Open the keyField Property and Select witch field is Key field.
All of above Steps should done at Design time. for testing your application add to edit box on your form as edit1 and edit2 then write a small code for OnCloseUp Evwnt of DBLookupCombobox like this
Edit1.Text:=DBLookUpCombobox1.KeyValue;
Edit2.Text:=DBLookupCombobox1.Text;
If you have problems with DBLookupComboBox you may use normal combobox and fill it like the example here.
After someone selects something in your DBLookupComboBox...The cursor to the table is moved.
You can access the value directly:
jenis.ListSource.DataSet.FieldByName('kd_jenis').AsString
This assumes that jenis is a TDBLookupComboBox.
That ListSource.DataSet points to Tb_jenis.
As Craig stated...you have a serious bug in your code...you need a RollbackTrans on exception...other wise you will never release the lock...
DM.koneksi.CommitTrans;
ShowMessage('Data Berhasil Disimpan');
except
DM.koneksi.RollbackTrans;
DM.Qbarang.Close;
DM.Qbarang.Open;
FormShow(sender);
end;
I do something like this...if I need to guarantee saving info and rolling back if fails.
procedure TForm8.SaveData;
begin
Assert(not ADOQuery1.Connection.InTransaction, 'Code problem-We should not be in a Transaction');
ADOQuery1.Connection.BeginTrans;
try
ADOQuery1.ExecSQL;
ADOQuery1.Connection.CommitTrans;
finally
if ADOQuery1.Connection.InTransaction then
begin
{If you are here...your in an ErrorState...and didn't Commit your Transaction}
ADOQuery1.Connection.RollbackTrans;
HandleError(ADOQuery1);
end;
end;
end;
I have a TSQLDataset, Im using the livebindings to bind it to a listbox. When I click on the listbox item, I want to be able to access the other fields of data from the record, but I cannot figure out how to do it because I cannot get the dataset to the corresponding item.
I know that I could possibly take the ID Field and maybe assign it to Selected.Tag using live bindings but can't figure that out either, but if I could then I could have another a SQLQuery and then just return the result of the query
SELECT * FROM Dataset WHERE ID=(Tag value)
That would work, but I don't know how to get livebindings to set the items tag value when live bindings populates the Listbox.
Does anyone know how to make this work?
It is easier to link Tag property of the ListBox with the ID of the record.
There's a Sensor Info demo application from Embarcadero in XE5 Samples directory...
There you have OnItemClick = lbMainItemClick in TListBox events then you have to define the event handler:
procedure TfrmAboutSensors.lbMainItemClick(const Sender: TCustomListBox; const Item: TListBoxItem);
begin
if Assigned(Item.OnClick) then
Item.OnClick(Item);
end;
And then for every item on the list:
for LItem in LListBox do
begin
//LItem.ItemData.Accessory := TListBoxItemData.TAccessory.aDetail; // my code
//LItem.ItemData.Accessory := TListBoxItemData.TAccessory.aNone; // my code
LItem.OnClick := ListBoxItemClick;
end;
Please give us callback if that helps.
Basic Scenario:
User clicks 'edit item'
Edit dialog opens
A combobox 'item type' should be populated with items form a table 'item_type'. The combobox should display 'item_type.name', but also know about 'item_type.id'
User edits other item stuff and selects an item type, then clicks ok
My program does some input validation
if everything is ok, get the 'item_type.id' from the selected combo item and save it to the foreign key column of the item table ('item.fk_item_type').
If I understand this component correctly, I should set DataSource to point to the destination table 'item' and DataField to 'item.fk_item_type'. But that would immediately edit my item table before I get a chance the validate all the other input.
It feels like I am missing something here. Somewhere I read that I need to use a classic ComboBox and fill it manually. But then I don't understand how to get to the id of the selected item.
Thank you for any pointers.
Edit:
I am starting to suspect that maybe I am missing a fundamental thing. All these DB* components, do they load values from that database automatically, but I have to call Post() myself? Meaning they do not automatically change values in the database?
If I understand you correctly, you want to use a DBLookupComboBox. You have to supply values for the following properties
datasource - linked to the table which you are editing, presumably 'items'
datafield - the name of the field in the table which you are editing, presumably 'item_type'
listsource - linked to the table which populated the combobox, presumably 'item_types'
list field - the name of the field from 'item_types' which you want to display, presumably 'name'
key field - the name of the field from 'item_types' which will be inserted into the items record, presumably 'item_type'
The table which populated the combobox is never edited.
You can validate the values before posting the new/edited 'items' record.
I can show you how to use a non-data aware combobox if necessary, but it's easier to use the data aware version.
Regarding validation, I use the following code template in edit dialogs.
Function TEditQuestion.Execute (n: longint): boolean;
var
gen: longint;
begin
sdsEditQuestion.params[0].asinteger:= n; // TSQLDataSet
with qEditQuestion do // TClientDataSet
begin
open;
if n = -1 then // new record
begin
caption:= 'New record';
insert;
fieldbyname ('alive').asinteger:= 1;
// initialise necessary fields in the dataset
end
else caption:= 'Editing record ' + inttostr (n);
edit;
if showmodal = mrOK then
begin
// validation code comes here. Set 'result' to true if everything is ok
if result then
begin
if n = -1 then
begin
with qGenID do
begin
open;
gen:= fields[0].asinteger; // get new value from generator
close
end;
FieldByName ('id').asinteger:= gen;
end;
post;
applyupdates (0)
end
else cancel // showmodal = OK, result = false
else // showmodal cancelled
begin
cancel;
result:= false
end;
end // with qEditQuestion
end;
I've been trying to make a creative thing to avoid the dbgrids, and i've found the Tlistview (using the one from alphaskins, tslistview), and seems to be a nice way!
The problem is, I don't want to code the event onclick on every tlistview to position a record/dataset according to the item I selected on the tlistview .. and I'm doing it with the tlistview item's caption.. and there could be records with the same names
Here is one of the codes I want to avoid:
with q_find_process do
begin
close;
sql.Clear;
sql.Add('Select * from t_process where process_name like '+quotedstr(streeview1.Selected.Text)+');
open;
end;
And no, I don't want to put the ID of the Record on the item caption..!
Any ideas?
Does anyone know other way of showing a lot of records without being only text text and more text? I don't know all components on the tool palette, maybe someone could suggest me other one..
I have sometimes used listviews which have been loaded from database tables - only for small amounts of data. I don't understand what you mean by I don't want to code the event onclick on every tlistview to position a record/dataset according to the item I selected on the tlistview, so I'm going to show you how I solved this problem.
Basically, I create a sub-item which holds the primary key of each record. All the user interface code uses two list views, and at the end, the database is updated. There is no interaction with the database between loading and storing (which might be where I avoid your 'onclick' problem). The widths of each fields are set in the Object Inspector; the final subitem's width is 0 (ie not displayed).
Loading the list view:
srclist.items.clear;
with qSrcList do
begin
close;
params[0].asdate:= dt; // use date of deposit
open;
while not eof do
begin
ListItem:= srclist.Items.Add;
ListItem.Caption:= fieldbyname ('kabnum').asstring;
ListItem.SubItems.Add (fieldbyname ('price').asstring);
ListItem.SubItems.Add (fieldbyname ('duedate').asstring);
ListItem.SubItems.Add (fieldbyname ('docket').asstring);
ListItem.SubItems.Add (fieldbyname ('id').asstring);
next
end;
close
end;
Saving data:
with dstlist do
for index:= 1 to items.count do
with qInsert do
begin
dstlist.itemindex:= index - 1;
lvitem:= dstlist.selected;
parambyname ('p1').asinteger:= deposit;
parambyname ('p2').asinteger:= strtoint (lvitem.SubItems[3]);
parambyname ('p3').asfloat:= strtofloat (lvitem.SubItems[0]);
execsql;
end;
I hope that this helps you. The context of this code (not that it matters too much) is in a financial application where the user wishes to populate a bank deposit form with cheques. SrcList holds the cheques which have yet to be deposited (there will only be a few per given date) and DstList holds the cheques which have already been connected to a given deposit form.
I am trying to use auto incremental fields in dbx4 with a black fish database
I have a simple table Structure:
CREATE TABLE tblTABname (
ID int AUTOINCREMENT Primary Key,
Description varchar(100) NOT NULL );
Before Open I am doing the :
qryTAB.FieldByName( ‘ID’).AutoGenerateValue := arAutoInc;
cdsTAB.FieldByName( ‘ID’).AutoGenerateValue := arAutoInc;
After Open:
qryTab.FieldByName('ID').ProviderFlags := [pfInWhere, pfInKey];
cdsTab.FieldByName('ID').ProviderFlags := [pfInWhere, pfInKey];
If I do:
cdsTAB.Edit;
cdsTAB.FieldByName(‘Description’).value := ‘Test’;
cdsTAB.Post;
Or if I use this in a DBGRID, it fails with the error :
“Field ‘ID’ must have a value”
Witch should have been generated .
If I run an INSERT Query it works fine, with or without the “AutoGenerateValue := arAutoInc” lines.
How can I overcome this problem?
Instead of calling CDSTab.EDIT, call CDSTab.INSERT to add a new row, only call CDSTab.EDIT when your cursor is on a record already, and to edit the value of that record.