can some body provide help me to use TFDTable.FireDac is completely new for me. I have used TTable in delphi 2010 for memory database. So i would like to use TFDTable in xe7 for temporary hold.
Well you need to read up on FireDAC generally if you are completely unfamiliar with it, and look at the examples that come with recent versions of Delphi.
But if you just want to know how to copy data from a FireDAC dataset that's connected to a database to an in-memory table, you can do it very simply, like this:
procedure TForm1.btnCopyToMemTableClick(Sender: TObject);
begin
FDMemTable1.Data := FDQuery1.Data;
FDQuery1.Close; // don't need it open any more
end;
Here, FDQuery1 is a TFDQuery, which is similar to a TQuery, in that it has a SQL TStrings property to allow you to specify what Sql query to execute to retrieve the data.
Related
The TSQLQuery class is unidirectional, so for it to be used as a source for a data-bound TDBGrid, a TClientDataSet needs to be linked between the TSQLQuery and the TDataSource that the TDBGrid is bound to.
I can connect the TSQLConnection and make the TSQLQuery active at design-time, with specified params, and then I can right-click on the CDS and choose the "Assign Local Data..." option to have it grab the data from the TSQLQuery, which then appears in the TDBGrid via the linked TDataSource.
The amount of time between choosing "Assign Local Data..." and the data actually appearing in the grid is very short, so I am looking for the way to replicate this at run-time.
Supposedly, I can set the Data property of the CDS to the Data of the source, but a TSQLQuery has no Data property. There was a post about using a provider, but
DataSetProvider1.DataSet := SQLQuery1;
ClientDataSet1.Data := DataSetProvider1.Data;
throws an access violation,
I did implement the data copy by looping through the TSQLQuery and appending the records to the TClientDataSet, but that was a lot slower than the "Assign Local Data...".
[Edit 1]
All the components I need are hooked up at design-time, and I can make the TSQLConnection active, then the TSQLQuery, then the TClientDataSet and the TDBGrid displays the data from the parameterised query defined in the TSQLQuery.
In the OnChange event of a TComboBox, I need to refresh the query using a different parameter and have the grid show the relevant results, so I Close the TSQLQuery, change the ParamByName value, Open the TSQLQuery and then call ClientDataSet1.Last to highlight the last row in the grid.
That gives me a "Cannot perform this operation on a closed dataset" error, so I use
ClientDataSet1.Active := true;
but that throws an "Access Violation".
All the examples I can find are all about dropping components onto a form, linking them together, and they work. Well, yes they do, but I need to change properties in code at run-time and still have it work, which it just refuses to do.
This is really beginning to frustrate me.
[Edit 2]
So I followed the example on the Embarcadero site for building a VCL Forms dbExpress Database Application, substituting my database connection details for the Interbase one the example uses.
http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Building_a_VCL_Forms_dbExpress_Database_Application
In the designer, everything looked fine and the grid was showing the results from the query, but when I went to run it using F9, I was getting an "Access Violation" thrown from within TCustomClientDataSet.InternalCheck.
Turns out this is a known MIDAS.DLL versioning problem and can be resolved by including MIDASLib in the uses clause of the form. It is just unfortunate that the Datasnap.DBClient code is still throwing Access Violations instead of proper messages, especially since this problem was reported in 2013.
You can use this code. Just change TUniConnection and TUniQuery to what You are using:
Procedure CdsAssignTable(aTableName:String; aCds : TClientDataSet; aCon
:TUniConnection );
Var
aQUery : TUniQuery;
aProvider : TDataSetProvider;
begin
if aCon=Nil then raise Exception.Create('aCon=Nil');
if aCds=Nil then aCds:=TClientDataSet.Create(aCon.Owner);
aQUery:=TUniQuery.Create(Nil);
aQUery.SQL.Text:='select * from '+aTableName;
aQUery.Connection:=aCon;
aQUery.Open;
aProvider:=TDataSetProvider.Create(Nil);
aProvider.DataSet:=aQUery;
aCds.Data:=aProvider.Data;
FreeAndNil(aProvider);
FreeAndNil(aQUery);
End;
I have application that has ADO connection on main form and several plugins that have ADO queries which I connect to this main connection. One problem is that I can't properly design those plugins without their personal connection which becomes messy when I connect plugins to main app. One plugin has plenty of queries.
I can use ConnectionObject to pass plugin's queries through main connection, but this is non-convenient for me, because when main connection needs to reconnect, I can't automatically reconnect all the queries. So I have to reassign those plugins' Connection property to main connection after plugin creation.
I know that one can list all active queries using ADOConnection's DataSets property. But what property should I use if I want to list both active and inactive DataSets? The IDE lists them automatically in designer, so I think there should be a generic way to do this.
Perhaps documentation regarding TADOConnection.DataSets which can be found here has confused you.
It says:
Use DataSets to access active datasets associated with a connection
component.
This might leed to thinking that DataSets keeps only active datasets which is not the case. To test this, just put one TADOConnection and one TADOQuery component on a form and set up TADOQuery.Connection to the instance of your connection, for example ADOConnection1.
To test that DataSets property keeps also inactive datasets you might use this code:
procedure TForm1.FormCreate(Sender: TObject);
var
i: Integer;
begin
for i := 0 to ADOConnection1.DataSetCount - 1 do
begin
if not ADOConnection1.DataSets[i].Active then
ShowMessage('Inactive dataset!');
end;
end;
I have been using Report Builder for some years, but I am getting tired of the cha-ching, cha-ching. It is a great reporting tool for "non database" reports.
I have started playing around with Fast Reports and I am utterly flustered with it. It seems a great reporting tool for databases but big question mark concerning complex "non database" reports. Their demos and help are horrible.
Wished I could show a report I am talking about. The report is a serial communications report that has operating system information which of course is single in nature. It has 4 distinct table which has installed serial ports and USB Serial Device tables. It also has a summary memo.
Has anyone successfully designed a report of the above configuration in Fast Reports? And yes, I have posted the same query with Fast Reports. Just want other opinions.
Thanks in advance.
I've extended the option provided by #jrodenhi's answer, which seems to be the proper way to do what you want (thus I've made this answer a community wiki). So here are the two options you can use (and I think there will be more of them):
1. Define custom variables
The answer by #jrodenhi shows how to add report variables in code. I'll try to show here, how to define them in report designer.
Open report designer
Go to menu Report / Variables...
In the Edit Variables window create a new category by clicking the Category button. Then you can rename the category the same way as you do e.g. for files in Windows Explorer:
Then you can declare a custom variable by clicking Variable button. You can give to the variable some meaningful name the same way as you do e.g. for files in Windows Explorer:
After this save your changes by clicking OK button:
Then you'll get back to the report designer, where you can find your just declared variables in the Data Tree pane tab Variables from where you can drag and drop the variables to the report:
After you refine all component positions and properties you can close the report designer and go back to the Delphi IDE. There you can write a handler for the OnGetValue event of your report and if its VarName parameter equals to your variable, change its Value parameter to the value you want to give to the associated report component:
procedure TForm1.frxReport1GetValue(const VarName: string; var Value: Variant);
begin
if VarName = 'MyVariable' then
Value := 'This is a new value!';
end;
2. Modify report components directly from Delphi code
There is an option of direct access to report components from your Delphi code. For instance, to find a certain report component by name you can use the FindObject method of the TfrxReport object. Then you can follow the usual pattern of checking if the returned reference is of type of the control you want to access and if so, you can access the instance by typecasting, as usually.
For example to find a TfrxMemoView object of name Memo1 on the frxReport1 report and modify its text you may write:
var
Component: TfrxComponent;
begin
Component := frxReport1.FindObject('Memo1');
if Component is TfrxMemoView then
TfrxMemoView(Component).Memo.Text := 'New text';
end;
Most of the reports I write are for payroll. In addition to the table based data that makes up the bulk of the report, there is usually a significant amount of singular data, such as user and employer information that is frequently most easily entered as a series of variables taken from a filter dialog that runs before the report. Once the filter has run I iterate through all of its variables and add them to the report variables. Maybe you could pick up your singular system variables and do the same.
This is my routine that runs just before I prepare a report. It not only adds variables, it also adds functions defined in Delphi that can be used in the report:
procedure TFastReportDriver.SetVariables(sVariables: String; var frxReport: TfrxReport);
var i,
iDetail: Integer;
sl: TStringList;
sVariable,
sValue: String;
begin
sl := TStringList.Create;
sl.CommaText := sVariables;
frxReport.Variables.Clear;
frxReport.Variables[' Filter'] := Null;
for i := 0 to sl.Count - 1 do begin
sVariable := sl.Names[i];
sValue := Qtd(sl.ValueFromIndex[i]);
frxReport.Variables.AddVariable('Filter', sVariable, sValue);
end;
frxReport.AddFunction('procedure CreateCheck(hPaystub, iCheckNo: Integer)');
frxReport.AddFunction('function NumberToWords(cAmount: Currency): String');
frxReport.OnUserFunction := repChecksUserFunction;
sl.Free;
end;
Then, in your code, you call frxReport.DesignReport and at run time you can drag and drop your variables onto your report:
And, if you have defined any functions like above, they show up under the functions tab.
I've had success with this method:
Use an in-memory table, such as TkbmMemTable, TdxMemTable or any in-memory table.
Link the in-memory table to the TfrDataSet.
Populate the in-memory table using usual TDataset methods and run the report.
You might want to take a look at using NexusDB as a way to hold data for the report. NexusDB is a database which besides being a full client server database can also run as a totaly in-memory database with full SQL support and no external dlls or anything required as it is compiled into your app. They have a free embedded version that will satisfy your needs. I use it for many things, it honestly a wonderful tool to have in your toolbox.
I have been asked by my company to update the reporting functionality of a paticular application written in delphi and using Quick reports to use FastReports instead.
The current implementation pulls all the data out of the database, does a lot of work to organise and calculate the required data for the reports and stores all this in several different objects. The Quick Report OnNeedData events are then used to fill out the bands until there is no more data (signified by setting MoreData = false)
The problem I'm having is Fast Reports seems to need a band to be connected to an actual data source, which I don't have. Also fastReports doesn't seem to have an event similar to OnNeedData.
Is there anyway to fill out the values of a data band in code and have it print again until all data is printed without connecting the band to a dataset?
I appologise for the vagueness of this question, I am very new to reporting software and any suggestions of where to go and what to look at would be greatly appreciated.
Fast reports use a intermediary object descending from _TFrxDataSet to connect the report engine which the data it prints.
To connect a report to a data source managed by the program itself, you use a TfrxUserDataSet component, which let's you see a data set inside the report, but you manually specify the column names in the Fields (TStrings) property and manage and supply values programatically writing event handlers for the following events:
OnCheckEOF is functionally equivalent to the OnNeedData, if there's no more to print, you set the EOF var parameter to true
OnFirst you do whatever you have to do to start walking for the data.
OnGetValue and OnNewGetValue you provide values for each of the different columns of the current row
OnNext, OnPrior you move your current row one next or one prior position.
As you see, the row/column concept (a DataSet) is used to provide the data to the report, but you can pull your data from any structure you use to store the result of your calculations (lists, arrays, or any other object/structure/file etc.)
Inside the report, you link the band to this logical DataSet and you use standard components to print the column values of this DataSet.
If you already have the data in a DataSet, for example a in-memory DataSet after your calculations, better use a TfrxDBDataset to directly bind your report to that source of data.
you can use TfrxUserDataSet.There is a demo named 'printstringlist' under folder 'demos'.
In our project we have implemented our own class inherited from TfrxCustomQuery. This new query class simply redirects its SQL statements to our application' internal query engine. We registered this new class in FastReport palette (used frxDsgnIntf.frxObjects.RegisterObject* for FR version 3 and 4) and now it is used in all our report templates instead of TfrxADOQuery or other built-in dataset classes.
Here is another alternative:
I've been using FastReport for years. I sometimes run into a similar situation. For offline tabular reports I use an in-memory dataset. I purchased DevExpress long time ago and so I have TdxMemData. But even without it, you should be happy using the TClientDataset component.
Besides that, the TfrxUserDataset is an alternative which I use when showing lists of objects.
There is a possibility to do it like this, it is slow though ,
Code:-
var
FRX: TfrxReport;
procedure NewPage;
begin
MyPage := TfrxReportPage.Create(FRX);
MyPage.CreateUniqueName;
MyPage.PaperSize := DMPAPER_A4;
end;
procedure ...(AText: string);
var
frMemo : TfrxMemoView;
begin
frMemo := TfrxMemoView.Create(MyPage);
frMemo.CreateUniqueName;
frMemo.Text := AText;
end;
Regards
Herman
how to insert blob data into oracle xe from delphi 7 (ado component)
Check these samples using a TAdoQuery component.
loading the data directly from a file
ADOQuery1.Parameters.AddParameter.Name:='Param1';
ADOQuery1.Parameters.ParamByName('Param1').LoadFromFile('yourfilename',ftBlob);
ADOQuery1.SQL.Add('INSERT INTO TableName (FieldName) VALUES (:Param1)');
ADoQuery1.ExecSQL;
using a Stream to load the data
ADOQuery1.Parameters.AddParameter.Name:='Param1';
ADOQuery1.Parameters.ParamByName('Param1').LoadFromStream(AStream,ftBlob);
ADOQuery1.SQL.Add('INSERT INTO TableName (FieldName) VALUES (:Param1)');
ADoQuery1.ExecSQL;
you must be aware which the Microsoft Oracle oledb driver is not compatible with blob fields try instead using the Oracle OLEDB provider.
As final advice if you can, try using another components to connect to ORACLE like dbexpress, ANYDAC or the ODAC components
Be aware that Oracle has a peculiar way to handle LOBs. It uses "LOB locators" (a sort of handles) to perform operations on LOBs. An INSERT returns a LOB locator that is then used to fill the LOB, for example. That operation could be performed "behind the scenes" by the driver/library used to access Oracle, or may require some coding.