How to find schema name in Oracle ? when you are connected in sql session using read only user

Call SYS_CONTEXT to get the current schema. From Ask Tom "How to get current schema:

select sys_context( 'userenv', 'current_schema' ) from dual;

To create a read-only user, you have to setup a different user than the one owning the tables you want to access.

If you just create the user and grant SELECT permission to the read-only user, you'll need to prepend the schema name to each table name. To avoid this, you have basically two options:

1. Set the current schema in your session:

ALTER SESSION SET CURRENT_SCHEMA=XYZ

2. Create synonyms for all tables:

CREATE SYNONYM READER_USER.TABLE1 FOR XYZ.TABLE1

So if you haven't been told the name of the owner schema, you basically have three options. The last one should always work:

1. Query the current schema setting:

SELECT SYS_CONTEXT('USERENV','CURRENT_SCHEMA') FROM DUAL

2. List your synonyms:

SELECT * FROM ALL_SYNONYMS WHERE OWNER = USER

3. Investigate all tables (with the exception of the some well-known standard schemas):

SELECT * FROM ALL_TABLES WHERE OWNER NOT IN ('SYS', 'SYSTEM', 'CTXSYS', 'MDSYS');