length 2048 too long for datatype nvarchar2. Length of nvarchar as i think depends on NLS_LANG. Max length is 4000 <b>Bytes</b>. But if NLS is UTF8 then we get error when try to create field with nvarchar2(2048) - We must decrease 2048 to 2000 because one symbol=2 bytes.
This is oracle error:

ERROR: ORA-00910: specified length too long for its datatype

Query
= CREATE TABLE triggers (
triggerid
number(20) DEFAULT '0' NOT NULL,

expression nvarchar2(255) DEFAULT
'' ,
description nvarchar2(255)
DEFAULT '' ,
url nvarchar2(255)
DEFAULT '' ,
status number(10)
DEFAULT '0' NOT NULL,
value
number(10) DEFAULT '0' NOT NULL,

priority number(10) DEFAULT
'0' NOT NULL,
lastchange number(10)
DEFAULT '0' NOT NULL,
dep_level
number(10) DEFAULT '0' NOT NULL,

comments nvarchar2(2048)
DEFAULT '' ,
error nvarchar2(128)
DEFAULT '' ,
templateid number(20)
DEFAULT '0' NOT NULL,
type
number(10) DEFAULT '0' NOT NULL,

PRIMARY KEY (triggerid)
);