How can I tell what tablespace a particular Oracle table or index resides in?

Resolution:
If the table or index is in the library's $data_root/file_list, that should show you the tablespace. If it is not, you should be able to see it in the util a/17/10/2 Merged file list (which gets its values from the file_list.xxx template in the $aleph_root/tab/ directory -- in addition to the $data_root/file_list).

Also, you can do the following SQL. (Note: you can be connected to any library in doing this.)
To get the tablespace for a particular Oracle table:

SQL> select tablespace_name from all_tables where owner = 'USR00' and table_name = 'Z303';

To get the tablespaces for all Oracle tables in a particular library:

SQL> select table_name, tablespace_name from all_tables where owner = 'USR00';

To get the tablespace for a particular Oracle index:

SQL> select tablespace_name from all_indexes where owner = 'USR00' and index_name = 'Z303_ID';

To get the tablespaces for all Oracle indexes in a particular library:

SQL> select index_name, tablespace_name from all_indexes where owner = 'USR00';

https://knowledge.exlibrisgroup.com/Aleph/Knowledge_Articles/How_Can_I_Tell_What_Tablespace_a_Particular_Oracle_Table_or_Index_Resides_In%3F