SQLite3Connection.databasename make exception "external SIGSEGV"
lazarus / 16-Databases

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vs99 · 2014-11-20 20:05

Hello,

I have problem with copile project on Win with SQLite.

SQLite3Connection.databasename:='test.db'; - make exception "external
SIGSEGV".

If I have the same code in MainForm, all do normally. But I move code
to second unit and from Unit1 call any procedures and functions with
SQLite3connection, appears exception. 

Anyone have an idea?

Thanks
Vladimir

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fpcoder · 2014-11-20 21:58

Vladimir,

"External SIGSEGV" usually means that the object you are trying to
access is not created yet. So check where you create
SQLite3Connection. (what form and when)

DataModules are good places to keep these things and also separate
database code from the rest of the program. I usually put my
Connection (named Conn) and Transaction (named TX) in a DataModule
(named DM) and call:

Code: [Select]DM.Conn.DatabaseName:= 'somedb';
If you do that, I suggest go to project options -> Forms and move the
datamodule up in the creation-list so it is created first of all. Then
you can access all the datamodule objects from any form that has your
datamodule in its uses clause.

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tudi_x · 2014-11-20 22:00

Hi,
Had the same issue.
Switched to Zeos components and no issue.
Example below:

Code: [Select]constructor Query.Create(TheDBFile, TheSQLiteDLL :
string);
    begin
      db_filename := TheDBFile;
      db_driver   := TheSQLiteDLL;
    end;


    function Query.RunQSQLite(AQuery : string) : boolean;
    begin
        ZConnSQLite                := TZConnection.Create(nil);
        ZConnSQLite.Protocol   := 'sqlite-3';
        ZConnSQLite.Database  := db_filename;
        ZConnSQLite.LibraryLocation:= db_driver;
        ZConnSQLite.Connect;

        Result := ZConnSQLite.ExecuteDirect(AQuery);
        ZConnSQLite.CleanupInstance;
        ZConnSQLite.Disconnect;
        ZConnSQLite.FreeInstance;
    end;

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vs99 · 2014-11-20 23:51

Thansk for all! 

I went through by Kapibara. It worked.

Info for others - after moving "DB Form" over "Main form" in Project
options you must create action "OnShow" on "DBForm" and put in to
DBForm.visible:=false;
Otherwise DBForm wil show on top application.