SQL> connect localhost:c:\data\damage.fdb user SYSDBA password masterkey;
Statement failed, SQLSTATE = 08006
Unable to complete network request to host "localhost".
-Error writing data to the connection.

SQL> connect c:\data\damage.fdb user SYSDBA password masterkey;
Statement failed, SQLSTATE = 08006
connection lost to database

C:\FireBird\bin>gfix -mend -user SYSDBA -password masterkey c:\data\damage.fdb
connection lost to database

Unsupported RDB$FORMATS record length: 20

Unsupported RDB$FORMATS record length: 20

WDWS12 (Client)	Wed Feb 10 10:51:00 2016
	INET/inet_error: read errno = 10054


WDWS12 (Client)	Wed Feb 10 10:54:07 2016
	XNET error: Server shutdown detected


WDWS12 (Client)	Wed Feb 10 10:55:35 2016
	INET/inet_error: read errno = 10054


WDWS12 (Client)	Wed Feb 10 11:13:31 2016
	XNET error: Server shutdown detected

update SOME_TABLE
   set NOT_NUL_INT = 0;

SQL> create table TEST ( ID integer not null primary key );
SQL> insert into TEST values( 1 );
Statement failed, SQLSTATE = 42S02
Dynamic SQL Error
-SQL error code = -204
-Table unknown
-TEST
-At line 1, column 13
SQL>

SQL> alter table TEST add VC varchar(16) not null;
SQL> update TEST set VC = ID;
Statement failed, SQLSTATE = 42S22
Dynamic SQL Error
-SQL error code = -206
-Column unknown
-VC
-At line 1, column 17
SQL>

create generator GEN_TEST_ID;

create table TEST (
    ID     integer not null,
    VAL    varchar(10),
    CALC   computed by ((ID + 100) / 10.0),
    STR    computed by (VAL || '=' || CALC),
    INS    timestamp,
    UPD    timestamp
);

alter table TEST
  add constraint PK_TEST primary key (ID);

set term ^ ;

create trigger TEST_BI for TEST
active before insert position 0
as
begin
  new.ID = gen_id( GEN_TEST_ID, 1 );
  if (new.VAL is null) then
    new.VAL = '<NULL>';
  new.INS = current_timestamp;
end ^

create or alter trigger TEST_BU for TEST
active before update position 0
as
begin
  new.UPD = current_timestamp;
end ^

set term ; ^