Help!! Database Schemas

Question

I'm a newbie in Oracle and OracleAS Portal, i'm doing my professional practices and i need a guidence.
I have a lot of questions but I'll start with this:
I don't completely understand what are the database schemas, I created one and I create tables in that schema and added data to those tables, bur I can use them...
so by creating an schema did I create sort of a database or not?
why do i have trouble connecting to that schema? like i tried to create a database link but this error came out:
The database link was created successfully, however, connection to the remote database using the link TRY2 cannot be established. (WWV-17135)
ORA-12154: TNS:could not resolve the connect identifier specified (WWV-11230)
Failed to parse as PRUEBA - Select 'Passed' from dual@TRY2 (WWV-08300)
or when i try to connect using SQL throws this error:
Connection wasn't stablished. [Listener refused the connection with the following error: ORA-12505, TNS:listener does not currently know of SID given in connect descriptor The Connection descriptor used by the client was: desarrollo06:1521:PRUEBA ]
DunkelBlume

Answer 1

Dunkel,
A database can contain many schemas. If you created a schema in Portal, you will not have created a new database. You do have a private space in the Portal database that you can use to create tables, as you have found out.
From elsewhere within Portal you don't need to create a database link. You can refer to the tables you created using the syntax SCHEMA_NAME.TABLE_NAME
You will have to grant access privileges to the tables to the user you are using to access them.
The easiest way to build a portal application is to create a database provider that is based on the schema you have created (if the schema is in the Portal database). Then all your tables are instantly available to any portal objects you care to create.
If your schema exists on a remote database server, then you will have to create a database link. My preferred way to do this is to create a schema on the Portal application server to contain the database link. I then create synonyms of the remote database tables, which effectively fools Portal into thinking they are local objects. The only exception to this are tables with LOB columns (BLOB, CLOB, etc) which won't work across a database link.
Hope this helps,
Patrick.