Writing to Mysql database

[Noobie]

Maybe this is a stupid question but if somebody could help.

How do I write a variable into mysql database?

If I try to...
INSERT INTO table (column1, column2, column3, ...)
VALUES (1, 2, 3);
... everything works

but when I use variables like...
INSERT INTO table (column1, column2, column3, ...)
VALUES (a, b, c);
... I will get an error.

[lucamar]

I'm not entirely sure (we use this format only for simple DB apps) but I think you have to use a parameterized "query", like:

Code: [Select]

INSERT INTO table (column1, column2, column3, ...)
VALUES (:a, :b, :c); and then add the values with something like:

Code: Pascal  [Select][+][-]

1. SQLQuery1.Params.ParamByName('a').AsInteger := a;

[MacWomble]

As
INSERT INTO table (column1, column2, column3, ...)
VALUES (a, b, c);
has to be a string it only works this way:
'INSERT INTO table (column1, column2, column3, ...)
VALUES ('+IntToStr(a)+','+IntToStr(b)','+IntToStr(c)+')';

So you can see, it's really better to use parameters like described before.
This is also better for strings, where you have to insert "Text..."

I use classes for this and a sample is:

Code: Pascal  [Select][+][-]

1.        Self.Items[i].fIsChanged := False;
2.         if Self.Items[i].fID = 0 then
3.         begin {Insert}
4.           DebugLn('  Datensatz wird neu angelegt');
5.           SQL.Clear;
6.           SQL.Add('INSERT INTO Artikel');
7.           SQL.Add(
8.             '(fk_artikelgruppe,  art_nummer, art_herstellernummer, art_name, art_beschreibung, art_datei)');
9.           SQL.ADD('VALUES');
10.           SQL.ADD(
11.             '(:fk_artikelgruppe,  :art_nummer, :art_herstellernummer, :art_name, :art_beschreibung, :art_datei);');
12.           Prepare;
13.         end
14.         else
15.         begin {Update}
16.           DebugLn('  Datensatz ' + IntToStr(Self.Items[i].fID) + ' wird aktualisiert');
17.           SQL.Clear;
18.           SQL.ADD('UPDATE Artikel Set');
19.           SQL.ADD('fk_artikelgruppe := :fk_artikelgruppe,');
20.           SQL.ADD('art_nummer := :art_nummer,');
21.           SQL.ADD('art_herstellernummer := :art_herstellernummer,');
22.           SQL.ADD('art_name := :art_name,');
23.           SQL.ADD('art_beschreibung := :art_beschreibung,');
24.           SQL.ADD('art_datei := :art_datei');
25.           SQL.ADD('WHERE idartikel = :idartikel;');
26.           Params.ParamByName('idartikel').AsInteger := Self.Items[i].fID;
27.         end;
28.         Params.ParamByName('fk_artikelgruppe').AsInteger :=
29.           Self.Items[i].fIDArtikelgruppe;
30.         Params.ParamByName('art_nummer').AsString := Self.Items[i].fArtikelnummer;
31.         Params.ParamByName('art_herstellernummer').AsString :=
32.           Self.Items[i].fHerstellernummer;
33.         Params.ParamByName('art_name').AsString := Self.Items[i].fBezeichnung;
34.         Params.ParamByName('art_beschreibung').AsString := Self.Items[i].fBeschreibung;
35.         Params.ParamByName('art_datei').AsString := Self.Items[i].fDatei;
36.  
37.         try
38.           ExecSQL;
39.           DebugLn('    Gespeichert !');
40.         except
41.           On E: Exception do
42.             debugln(' ' + E.Message);
43.         end;

[Noobie]

Thanks guys! I'll try that.