[FireDAC](Comp)[DS]-306. Command [FDTable] text must be not empty. (solved)

[JohnLM 22]

I'm trying really hard to figure this message out, but can't. 

 

What part of the TFDTable 'text must not be empty' that i need to fill in ?

 

1. I have a form with a memtable and stringgrid on left side of form.

2. Also have a dbgrid with (con, table, query, datasource) components on right side of form.

3. a button to [import] the data from the stringgrid into the dbgrid.

 

Below, is code to import data into the FDTable. I am just trying to learn how to import data through this method. Not trying to do it another method or way. So, I want to know what is the meaning and solution to the 'text must not be empty' part. I don't know what text the message is refering to when i run this code and click on the [import] button, below... thanks.

procedure TForm1.btnImportClick(Sender: TObject);
begin
  //
  ftable.CopyDataSet(memtable, [coStructure, coRestart, coAppend]);
end;

 

solved... (partially) - see my posts below, I explained why it was happening and what I did to resolve it. -- 12/29/2022 Friday pm 

Edited December 29, 2022 by JohnLM

[programmerdelphi2k 237]

John

look, StringGrid (FMX/VCL) /Grids (in FMX) works like a mem-Repository! All data, in fact, will be "string" values!

Then, if you need export data to "FDTable", you'll go needs a "converter"!

You can use "TBatchMove" components: BatchMove, BatchMove(Dataset/Text)Writer, BatchMove(Dataset/Text)Reader to work "directly" on Datasets: TFDMemTable and FDTables!

So, in FDMemTable you create the same "fields" that you need export to FDTable: same names (or not), same types.

BatchMove do the magic: read data-sources on FDMemtable and write on target-FDTable

see sample on 

https://en.delphipraxis.net/topic/7991-batchmove-using-firedac-missing-fieldnames-and-tablename-solved/?tab=comments#comment-67218

 

NOTE: FDMemTable can store your data in XML, JSON and FD binary... and you can define it using property:

• ResourceOptions ->PersistentFileName ....  (check the property Persistent[x] ) and right-click on component and save to file...  (before, you need create your fields)

Edited December 29, 2022 by programmerdelphi2k

[weirdo12 21]

Do you have a SELECT query in the Command property of the TFDTable component?

[JohnLM 22]

After some more investigating, it seems that which ever component I use, (fdquery or fdtable), I have the have its SQL text filled out, as in something like "select * from tblBarcodes" for instance. 

 

So, the CopyDataSet(memtable, [coStructure, coRestart, coAppend]) feature is not compatible with the TFDMemTable in some way. 

 

I already know about and how to use batchmove and other methods for this process above.  I was simply trying the copydataset() to see how that works because I've read about it many times and being in this particular case/situation I thought I would try it out. 

 

So, working with the TMemTable and FDQuery/FDTable together, is not a good idea for any projects then, if you can't copy from it, the table structure, etc., if I want to then create a actual database file, i.e., SQLite db. 

Edited December 29, 2022 by JohnLM

[weirdo12 21]

15 minutes ago, JohnLM said:

So, working with the TMemTable and FDQuery/FDTable together, is not a good idea for any projects then, if you can't copy from it, the table structure, etc., if I want to then create a actual database file, i.e., SQLite db. 

 

From what I gather, you were assuming CopyDataSet would automatically create a new table in an SQLite database. Is that correct?

[JohnLM 22]

Not quite. 

 

The goal was to have a stringgrid and populate it with barcodes that I would scan with my smartphone (android). Then, if I need the data finalized (stored) then I would export it out to a sqlite database on the phone.  But first, I would need to visualize the data in some similar grid. And if I like it, I would [save] to a sqlite db on the phone. I might want to edit the data before I export it out, so the second grid would serve that purpose. 

 

Yes, I know, I could and should do it in one table/grid but I will be doing a lot of what-ifs and not needing to export or update data in real-time. I feel, in my opinion, that this is my prefered route for this project, until I decide otherwise.., this will do. 

 

 

[JohnLM 22]

And, by the way, I found the solution, just before you posted before my previous post above.

[JohnLM 22]

The solution I found (through trial and error) through the steps below, works. 

 

In the fdquery->SQL I added the following: 

 

drop table if exists tblBarcodes;
create table if not exists tblBarcodes (
IDNo integer,
Barcode varchar(255),
isle integer,
LFRT varchar(2),
Row integer,
Type varchar(2),
Date varchar(21),
Desc varchar(255)
)

 

In my form create section, I have this bit of code: 

var
  DATABASE_FILE: string;
begin
  DATABASE_FILE := TPath.Combine(TPath.GetDocumentsPath, 'mydb.db');
  DATABASE_FILE := 'f:\datasets\mydb.db'; // <-- rem this line out when compiling over to android. <-- 
  Con.Params.Clear;
  Con.Params.Add('DriverID=SQLite');
  Con.Params.Add('Database=' + DATABASE_FILE); //DATABASE_FILE);
  con.Params.Add('create database'+database_file);
  Con.ResourceOptions.DefaultParamType := ptOutput;
  Con.Connected := True;

 

In my [import] tbutton, I have following code:

procedure TForm1.btnImportClick(Sender: TObject);
begin
  // import the database into the second grid for review.
  qry.Close;
  qry.data := mtable.Data;
  qry.open;
end;

Note, the second grid is a dbgrid.  Once I convert this portion of code over to the FMX platform (and then Android) the grid will be a stringgrid.

 

 

The left side grid is the scanned barcodes, the right side grid is the copied grid/contents from the left side grid.

 

Thus, while I debug my actual mobile barcode scanner app (at my job site), I will be running various scanning tests. So, I will be creating and deleting a number of times the contents in the left side grid, and sometimes I may be import it to right side grid, and then posibly save it out to an sqlite db for further review.

 

Note, I have not tested it for mobile. But I plan to soon. 

 

Edited December 29, 2022 by JohnLM

[weirdo12 21]

On 12/29/2022 at 3:33 PM, JohnLM said:

In my [import] tbutton, I have following code:

procedure TForm1.btnImportClick(Sender: TObject);
begin
  // import the database into the second grid for review.
  qry.Close;
  qry.data := mtable.Data;
  qry.open;
end;

 

 

I was going to point out the Data property but you said you only wanted to discuss CopyDataSet() 😄 Good to hear you've got a solution.