dba_tables，dba_all_tables,user_tables,all_tables有什麼區別

oracle官方文件的說明
1.DBA_ALL_TABLES describes all object tables and relational tables in the database. Its columns are the same as those in ALL_ALL_TABLES.

2.ALL_ALL_TABLES describes the object tables and relational tables accessible to the current user.

3.USER_ALL_TABLES describes the object tables and relational tables owned by the current user. Its columns (except for OWNER) are the same as those in ALL_ALL_TABLES.