How to interpret trigger meta data?

The values that you're getting are object identifiers (OID). CUBRID is an object-relational database. All tables in CUBRID are classes and they can be inherited or can inherit from other classes, also you can aggregate tables. The owner column from  db_trigger is an object of type db_user (the table db_user) and the value that you're seeing there is the OID (object identifier). 

For your actual question, the schema of the class db_trigger is described here:

http://www.cubrid.org/manual/841/en/db_trigger

It has two object columns: 

• the field owner is an object of type db_user
• the field target_class is an actual class

 SELECT * FROM db_trigger where target_class = class x;

If you want to get the name of the owner (the user) of the trigger, you can run the query:

SELECT owner.name from db_trigger where target_class = class x; 

You can find all the names of the tables which have triggers, you have to join db_trigger class with _db_class class

 SELECT c.class_name FROM _db_class c inner join db_trigger t ON t.target_class = c.class_of

See also:

http://www.cubrid.org/manual/821/en/Class%20Inheritance

and

http://www.cubrid.org/questions/318023