How do I connect to the default Oracle10g instance on my PC? - oracle

Question

I have a strong SQL Server background but fairly new to Oracle. I have a Windows 10 Home Edition. I installed Oracle 10g along with Oracle SQL Developer. What credentials/settings do I need to do to specify in SQL Developer to connect to the default Oracle database (if one exists)?

Answer 1

Well, that depends on what exactly you installed. Which Oracle 10g version? XE? Standard? Enterprise? As far as I can tell, Oracle was never certified on any Windows Home edition. It's not that it won't work at all, it just depends.
By the way, why 10g? It is outdated; the most recent version is 18c (available for download on Oracle Technology Network, https://www.oracle.com/downloads/).
As you are new to Oracle, I'd suggest you to use XE (Express Edition). Even 10g would do, I presume (if that's what you installed). For amusement, I have 11gXE on my Windows 7, works well. Why? Because it is a small footprint database, fully functional, free to use. It has its restrictions (such as 1 CPU, 1 GB RAM, 8 GB of user data) (those restrictions depend on XE version), but it is OK for most purposes.
Moreover, it automatically installs the database you can start using. During the installation process, you're asked for password for SYS (and SYSTEM) users (they "own" the database). Once you know these, you're the boss.
In XE, you have pre-installed schemas (i.e. users with their objects: tables, views, ...) which are named Scott, HR (Human Resources). By default, they are locked so you'd have to connect to the database as SYS and unlock them.
As you already have SQL Developer, you'd create a connection:
username = SYS
password = you know it
connection type = Basic
role = default
hostname = localhost
port = 1521 (it is the default; if you use some other port, you'll know it)
SID = xe (by default)
Once you're connected, check which users you have
select username, account_status from dba_users;
As I've said, Scott and/or HR might be interesting for you as they already have some objects. See their status; if they are locked, you'd unlock them and set new passwords as
alter user scott account unlock;
alter user scott identified by tiger;
Now you can create a new connection to Scott, following the same instructions as above.
If you want to create your own user, no problem. Still connected as SYS, check available tablespaces (this is SQL*Plus output, command-line tool; in SQL Developer, you won't have the "SQL>" prompt):
SQL> select tablespace_name from dba_tablespaces;
TABLESPACE_NAME
------------------------------
SYSTEM
SYSAUX
UNDOTBS1
TEMP
USERS
SQL> create user sam identified by nasr
2 default tablespace users
3 temporary tablespace temp
4 quota unlimited on users;
User created.
Once the user is created, it can't do anything - you have to grant it certain privileges, such as :
SQL> grant create session, create table, create view to sam;
Grant succeeded.
Create session allows it to establish connection; another two will let you create tables and views. If you - as the time goes by - need yet another privilege, connect as SYS and grant it the same way.
Now you can connect to it (that would be yet another connection in SQL Developer) and ... do something:
SQL> connect sam/nasr
Connected.
SQL> create table test (id number);
Table created.
SQL> insert into test (id) values (100);
1 row created.
SQL>
So: if you have anything but XE, I'd suggest you to uninstall it. Use Universal Installer to do that. Then download and install XE. In my opinion, as Oracle beginner, that should make your life easier.
On the other hand, if you want to practice to be a DBA, then XE probably isn't the right choice as there can be only one - preinstalled - database.