FireDAC SQLITE : No such table column :PRAGMA_TABLE_INFO

问题

i'm building app with delphi rio 10.3 with firedac sqlite3

pragma function not working with 'SELECT COMMAND' AS I Try Below:

procedure Tamdf.Button31Click(Sender:TObject);
begin
   MyFDQuery.Open('SELECT name FROM PRAGMA_table_info("DOCM")');
   ShowMessage(MyFDQuery.Fields[0].AsString);
end;

i receive ERROR message :"ERROR: no such table column: PRAGMA_table_info.name" what i did wrong ?

回答1:

With FireDAC you can use workaround with create temp table "table_info":

MyFDQuery.Open(
  'DROP TABLE IF EXISTS table_info;' +
  'CREATE TEMPORARY TABLE table_info AS SELECT * FROM pragma_table_info("DOCM");' + 
  'SELECT name FROM table_info');

Edit

My environment: Delphi 10.3.2 Rio, Win32, default SQLite 3.28.0 statically linked. No special settings.

Connection - TFDConnection with only:

FDConnection1.Params.DriverID := 'SQLite';
FDConnection1.Params.Database := 'D:\TMP\TEST.db';

回答2:

The following code works fine for me on a Sqlite database containing the table `MyTable'. I'm not sure the SQL you are using is correct for use in FireDAC

procedure TForm3.Button1Click(Sender: TObject);
begin
  if FDQuery1.Active then
    FDQuery1.Close;
  FDQuery1.Open('PRAGMA Table_Info(''MyTable'')');
end;

It returns

 cid    name
 0       ID
 1       NAME

If nothing else, you could use FireDAC's LocalSQL to extract the Name from the returned result set.

I'll see if I can get SELECT working with the PRAGMA query ...

This query works fine in FireFox's Sqlite Manager add-in

select * from PRAGMA_table_info('mytable')

but returns the error

no such table: PRAGMA_Table_Info'.

when executed by FDQuery1.

来源：https://stackoverflow.com/questions/58661727/firedac-sqlite-no-such-table-column-pragma-table-info

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