begin
if not exists (select  1  from dba.const where short_name = 'INS_ID')
then insert into dba.const(const_id, short_name)
values ( 30 , 'INS_ID', 'Код (из справочника)');
end if;

// дальше ALTER TABLE (добавляется колонка в таблицу)
......скип.........
end;

SQL.LoadFromFile(search_path + sr.Name);
open;

insert into ...;
select @@identity

Query1->SQL->Clear();
Query1->SQL->Add("insert into MasterTable (Value) values ('10');");
Query1->SQL->Add("select @@identity");
Query1->Open();

void __fastcall TDataBases::DataModuleCreate(TObject *Sender)
{
   try
   {
      Database->AliasName="TestSybaseByODBC";
      Database->Params->Clear();
      Database->Params->Add("HOST NAME=localhost");
      Database->Params->Add("SERVER NAME=TEST_SRV");
      Database->Params->Add("DATABASE NAME=testdb");
      Database->Params->Add("USER NAME=sa");
      Database->Params->Add("PASSWORD=");
      Database->DatabaseName="testdb";
      Database->LoginPrompt=false;

      Session1->SessionName="TestSession";
      Database->SessionName=Session1->SessionName;

      Database->Open();
      if(Database->Connected)
      {
         Query1->DatabaseName="testdb";
         Query1->SessionName=Session1->SessionName;

         Query1->SQL->Clear();
         Query1->SQL->Add("if not exists (select 1 from sysobjects where (id=object_id('TestTable')) and (type='U')) create table TestTable(ID numeruc(18) identity, Name varchar(256) null) lock datarows with identity_gap=10");
         Query1->SQL->Add("go");
         Query1->SQL->Add("insert into TestTable (Name) values ('Иванов Иван Иванович')");
         Query1->SQL->Add("go");
         Query1->ExecSQL();
      }
   }
   catch(EDBEngineError &eException)
   {
      ShowMessage("EDBEngineError: Message=\""+eException.Message+"\"");
   }
   catch(EDatabaseError &eException)
   {
      ShowMessage("EDatabaseError: Message=\""+eException.Message+"\"");
   }
   catch(Exception &eException)
   {
      ShowMessage("Exception: Message=\""+eException.Message+"\"");
   }
}
//---------------------------------------------------------------------------

Query1->SQL->Clear();
Query1->SQL->Add("if not exists (select 1 from sysobjects where (id=object_id('TestTable')) and (type='U')) create table TestTable(ID numeric(18) identity, Name varchar(256) null) lock datarows with identity_gap=10");
Query1->SQL->Add("insert into TestTable (Name) values ('Иванов Иван Иванович')");
Query1->SQL->Add("insert into TestTable (Name) values ('Петров Петр Петрович')");
Query1->ExecSQL();