DBAccess.Create not working

[Milsa]

What's wrong? TFormMain.FormCreate calls DBAccess.Create but it's not working. Constructor will finish on begin command.

[howardpc]

You are not instantiating your classes correctly. In form_main, instead of

Code: [Select]

DBAccess.Create(Self);
you should have

Code: [Select]

DBAccess:=TDBAccess.Create(Self);
Likewise in class_db_access in place of

Code: [Select]

SQLite3Connection.Create(AOwner);
you should have

Code: [Select]

SQLite3Connection:= TSQLite3Connection.Create(AOwner);
The same applies to your 'creation' of SQLTransaction.
You've also omitted to call the inherited Create constructor in TDBAccess.Create. The first line of TDBAccess.Create after begin should be

Code: [Select]

inherited Create;
I also recommend you change the declaration of DBAccess to

Code: [Select]

var DBAccess: TDBAccess=nil;
It is never be wrong to initialise a variable, and with pointer variables especially, it can often save your bacon when you realise you've got an unexpected nil value somewhere later in the program.

[Milsa]

Code: [Select]

DBAccess.Create(Self);This is correct Lazarus syntax (not Delphi).

[Milsa]

Thank you. it works.

I've read that this syntax is correct but it's not working correctlly.

Code: [Select]

SQLite3Connection.Create(AOwner);It is reportedly same that:

Code: [Select]

SQLite3Connection := TSQLite3Connection.Create(AOwner);

[howardpc]

Code: [Select]

DBAccess.Create(Self);This is correct Lazarus syntax (not Delphi).

It is only 'correct' in the sense that it happens to compile without errors (unfortunately). It is incorrect in that it does not do what is needed, namely instantiate a new instance of the TDBAccess class.
As you have coded it, DBAccess is a global variable, and so will be set to nil by compiler code during initialization. Thereafter

Code: [Select]

DBAccess.Create(Self);
is in fact

Code: [Select]

nil.Create(Self);
Unsurprisingly this causes a SIGSEGV.