IBM DB2, create an alias to database with schemas and tables - db2

Question

I have a database (list db directory):
Database 4 entry:
Database alias = ABC
Database name = ABC
Local database directory = /data
Database release level = f.00
Comment =
Directory entry type = Indirect
Catalog database partition number = 0
Alternate server hostname =
Alternate server port number =
I need to have an alias for that database because my application tries to connect to database DEF.
I can create an alias using
catalog db ABC as DEF
then the (list db directory) shows:
Database 4 entry:
Database alias = ABC
Database name = ABC
Local database directory = /data
Database release level = f.00
Comment =
Directory entry type = Indirect
Catalog database partition number = 0
Alternate server hostname =
Alternate server port number =code here
Database 5 entry:
Database alias = DEF
Database name = ABC
Local database directory = /data
Database release level = f.00
Comment =
Directory entry type = Indirect
Catalog database partition number = 0
Alternate server hostname =
Alternate server port number =
But after I connect to aliased db using:
db2 connect DEF
I can't access any schemas and tables from original database. Of course when I connect using ABC database name everything is visible and on place.
Am I misunderstanding aliases in DB2? Or maybe there is some option like "create an alias with data" or something like that?

Answer 1

You seem to misunderstand the purpose of a database-alias produced by db2 catalog database ABC as DEF.
For Db2 for Linux/Unix/Windows, a database ALIAS is not a SCHEMA.
You cannot use the new alias in SELECT or other SQL statements.
You can only reference the database-alias in the CONNECT step. After successful connection, use SQL as if you had connected to database ABC only.
The database-alias is only a pointer to a database.
The database being pointed to (in your case ABC) does not change, and the schemas inside it do not change, and you cannot change how you refer to objects like tables and views in those schemas.
In your SELECT (or other SQL statements) you must refer to the schemas that are present inside the physical database. So there really is not schema called DEF, becase DEF is an alias known only to the command-line-processor and db2-database-directory. If you wish to make new synonyms inside the database you are free to do that , but that is NOT the purpose of database-aliases.
As you seem to be running Db2 for Linux/Unix/Windows with local databases (Directory entry type = Indirect), you should connect to each database ABC and DEF and run both of the queries below and then compare their outputs from each database, and update your question with the outputs.
select char(os_name,20) as os_name
, char(os_version,5) as os_version
, char(os_release,20) as os_release
, char(host_name,30) as host_name
from sysibmadm.env_sys_info;
select char(inst_name,15) as inst_name
,char(release_num,20) as release_num
,char(service_level,20) as service_level
,char(bld_level,20) as bld_level
,char(ptf,20) as ptf
from sysibmadm.env_inst_info;

Answer 2

#mao - You are right!
I've been connected using external software to one node, and using shell db2 to other node. That was the reason that i wasn't able to see databases.