SQLite Lazarus
lazarus / 16-Databases

----------------------------------------------------------------------
odvesims · 2015-06-10 14:11

Hey There!!

I've recently started working with Lazarus and im having issues with
SQLite.

Thing is, i want to have a class (will call it DataBaseHerlper) that
will manage all transactions with my DB and i want to be able to call
the functions in it from other classes. I'm capable of reading/writing
to the database if i do it directly on my form unit, but i dont wanna
have to code it everywhere.

As i mentioned before, i want to have all the methods that will deal
with DB procedures in the same unit. Problem is, when i try to connect
to the database via that unit, it throws a "External:SIGSEGV" error. I
have no idea how to fix this.

In the login form i called the method that's in my DataBaseHelper unit

Code: [Select]helperDB.getCertificate();

This is the function in the DataBaseHelper unit:

Code: [Select]SQLite3Connection1.DatabaseName:='PrescoTermDB.db';
SQLite3Connection1.Connected:=true;
SQLTransaction1.Database:=SQLite3Connection1;
SQLQuery1.Database:=SQLite3Connection1;
SQLQuery1.SQL.text:='Select * FROM Certificates';
SQLQuery1.open;                               

The error is thrown at the 1st line listed above. Its the "External:
SIGSEGV" error. I read somewhere someone had the same error (though
they were using PostgreSQL) and they fixed it by instantiating the
objects (SQLite3Connection, SQLTransaction, etc) this way:

Code: [Select]SQLite3Connection1:=TSQLite3Connection.Create(nil);
OR

Code:
[Select]SQLite3Connection1:=TSQLite3Connection.Create(Application);
(This requires "Forms")

But that didnt work for me either.

Anyone knows how can i get this to work? Im sure it's something
simple, but I'm not really familiar with Pascal/Lazarus. I've done
this easily in Java/Ruby/C++, Here... No luck.

----------------------------------------------------------------------
odvesims · 2015-06-10 14:31

Agh! I knew it was something rather simple. It had to do with where i
placed my variables in the "DataBaseHelper" unit.. It was outside the
"implementation" variables section. My bad!

I guess I should do more reading about class's structures in Pascal..

----------------------------------------------------------------------
hrayon · 2015-06-10 14:41

Hi!
I don't use TSQLite3Connection, but try use full path name to
''PrescoTermDB.db'.
If you will connect to db inside a method, disconnect it there, it's
safest.
It's usual to connect to db, share the connection while needed, and
disconnect when not necessary.
Perhaps this way may change the program logic in some aspects.
Sorry my english.