Creating a database link to another schema in the same database

Question

Hello,
I'm trying to create a database link to another schema in the same database. It was created without errors, but when I try to use it I receive "ORA-12154: TNS:could not resolve the connect identifier specified" message...
I'm trying to do it because on my production enviroment the databases are separated, so there I can use database links without problem, but in my development environment it's all in one database separated by schemas...
So I'm trying to simulate the same system to not need to rewrite the query every time I move from development to production environment.
Any ideas?
Thanks

Answer 1

Hi,
Yes, you can create a database link to your own database. I've done it before for exactly the same reason you want to.
(By the way, I think it's a good reason. What are the alternatives?
Having different versions of code for Development and Production? Absolutely not! Terrible idea!
Using synonyms or substitution variables that are set differently in the different databases? That might be more efficient than a database link, but efficiency probably isn't such a big issue in Development.
[Conditional compilation|http://download.oracle.com/docs/cd/B28359_01/appdev.111/b28370/fundamentals.htm#sthref250]? This might be good; it has all the efficienty of the above options, with more clarity.)
Assuming you do want to stick with a database link, not all errors are caught when you create the link.
Is the Development database in the tnsnames.ora file of the Development server? Do you have other database links, either in the Development server or pointing to it, that work? What is different about the ones that work, and the one that doesn't?
Edited by: Frank Kulash on Oct 14, 2009 1:58 PM
The more I think about this, the more I agree with the earlier respondent: synonymns are a good solution for this.
To that suggestion you replied:
On this way I might use "select * from SCHEMA.table" instead of "select * from table@SCHEMA"... I looking for an option to use the second way...Actually, the suggestion was that you say:
select  *
from    SCHEMA_table_ptr;where schema_table_ptr is a synonym.
In Development, that synonym is defined as schema.table.
In Production, that synonym is defined as table@SCHEMA
Why are you "looking for an option to use the second way"?
If you think that people reading the code should realize that the query is being done via a database link (at least in Production), then add a comment.