Forum > Databases

Replace substring in a field and update DB

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WJSwanepoel:
Thanks, I shall try and battle thru it on my own.

Thaddy:
You can battle, but that will probably not work soon.
As promised:
--- Code: Pascal  [+][-]window.onload = function(){var x1 = document.getElementById("main_content_section"); if (x1) { var x = document.getElementsByClassName("geshi");for (var i = 0; i < x.length; i++) { x[i].style.maxHeight='none'; x[i].style.height = Math.min(x[i].clientHeight+15,306)+'px'; x[i].style.resize = "vertical";}};} ---Program sqlite_test_tdk;{$mode objfpc}{$H+}{$ifdef mswindows}{$apptype console}{$endif} Uses SysUtils, sqldb, sqlite3conn; Const   db = 'test.db'; Var   Conn: TSQLite3Connection;  Query: TSQLQuery;  Txn: TSQLTransaction;  Id: integer = 2;  TextField: string;BeginTry  Conn := TSQLite3Connection.Create(Nil);  Try    Conn.DatabaseName := db;    Try      Txn := TSQLTransaction.Create(Nil);      Try        Conn.Transaction := Txn;        If Not FileExists(db) Then          Try            Conn.Open;            Conn.ExecuteDirect('CREATE TABLE "content" ( "topic_id" Integer NOT NULL PRIMARY KEY AUTOINCREMENT,"data" VARCHAR)');            Conn.ExecuteDirect('INSERT INTO "content" VALUES (1, "DATA 1")');            Conn.ExecuteDirect('INSERT INTO "content" VALUES (2, "DATA 2")');            Conn.ExecuteDirect('INSERT INTO "content" VALUES (3, "DATA 3")');            Txn.Commit;            Conn.Close;          Except            On E: Exception Do              writeln('Could not create database: ',db);          End;        Try          Query := TSQLQuery.Create(Nil);          Try                         Query.Database := Conn;            Query.SQL.Text := 'SELECT topic_id, data FROM content WHERE topic_id = :id';            Query.ParamByName('Id').AsInteger := Id;            Query.Open;            TextField := Query.FieldByName('data').AsString;            Writeln('The value of TextField is: ', TextField);            // Change the value of TextField            Query.Edit;            Query.FieldByName('data').AsString := 'Changed Topic '+DateTimeToStr(Now);            TextField := Query.FieldByName('data').AsString;            Writeln('The value of TextField is now: ', TextField);            // Commit the change            Try              Query.Post;              Query.ApplyUpdates;              Txn.Commit;            Except              // Usually EUpdateError              On E: Exception Do                writeln(E.Message)             End;           Finally             Query.Free;           End;         Except           On E: Exception Do           writeln('Could not Create Query:', E.Message);         End;       Finally        Txn.Free;       End;     Except        On E: Exception Do          writeln('Could not create transaction: ',E.Message);     End;   Finally     Conn.Free;   End;Except  On E: Exception Do writeln('Could not create connection: ', E.Message);End;  writeln('Press any key');  readln;End.Done. Maybe only specialize the exception objects a bit. (EDatabaseError or derived from EDatabase error, like EUpdateError)

WJSwanepoel:
Thank you for the help. I will try to apply myself and get it working.

Thaddy:
I editted the code somewhat because as an oversight I handled the try finally's not correctly. Brought the creation of the class instances outside of their subsequent try finally block. As it should be.

WJSwanepoel:
Thank you, much appreciated.

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