Question

I have a public synonym on my server for transactions: However I’d like to be able to work with my own local version of the table, so as not to disturb other users.

Does Oracle’s SQL resolve naming conflicts like this in a predictable fashion?

In other words, if another user creates a public synonym called TRANSACTION and I do this:

CREATE TABLE TRANSACTION (

ID NUMBER

);

When I write

select * from TRANSACTION

Do I have any guarantee that Oracle will always resolve the synonym or my local table?

(I know I could technically specify schema.TRANSACTION to force the issue, but in my case that would require me to modify/rebuild an application and I’m hoping to save some work.)

Answer 1

Your understanding of name resolution is correct. Oracle will first look in the current schema to find an object with that name. So, In case of a conflict, It will choose an object in the current schema instead of the object referred to by the public synonym.

http://docs.oracle.com/cd/B28359_01/server.111/b28310/general008.htm

Oracle Database attempts to qualify the first piece of the name
referenced in the SQL statement. For example, in scott.emp, scott is
the first piece. If there is only one piece, the one piece is
considered the first piece.

In the current schema, the database searches for an object whose name
matches the first piece of the object name. If it does not find such
an object, it continues with step b.

The database searches for a public synonym that matches the first
piece of the name. If it does not find one, it continues with step c.

The database searches for a schema whose name matches the first piece
of the object name. If it finds one, it returns to step b, now using
the second piece of the name as the object to find in the qualified
schema. If the second piece does not correspond to an object in the
previously qualified schema or there is not a second piece, the
database returns an error.

If no schema is found in step c, the object cannot be qualified and
the database returns an error.

Having said that, this is one of the problems with public synonyms. Having objects like this will lead to confusion down the road, both for development and support. You are better off referencing the object by owner and name in both cases