This morning I was unable to access my Oracle database which runs on my laptop. It’s the first time I have had this problem.

When I tried to login I saw this.

$ sqlplus foo/foo@dev01

SQL*Plus: Release 10.2.0.1.0 - Production on Thu Jul 3 06:38:20 2008

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

ERROR:
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

When I tried to login without the TNS alias I saw this:

$ sqlplus foo/foo

SQL*Plus: Release 10.2.0.1.0 - Production on Thu Jul 3 06:38:20 2008

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist

On the internet I saw recommendations to set your ORACLE_SID and ORACLE_HOME environment variables. But on my system ORACLE_SID is not set and ORACLE_HOME is blank. Finally I just tried restarting the OracleServiceDEV01 service and that worked.

(Photo: Dolphin Crest by jurvetson)

I was wondering how to do this and thankfully someone wrote up a nice article on the SQL update statement.

Here is their example of how to do this.

UPDATE suppliers
SET name =
  ( SELECT customers.name
  FROM customers
  WHERE customers.id = suppliers.id)
WHERE EXISTS
  ( SELECT customers.name
  FROM customers
  WHERE customers.id = suppliers.id);

Thanks to this article, Oracle/PLSQL: Change a user’s password in Oracle, it was quite simple to change a user’s password.

SQL> alter user frank identified by password;

Whenever I tried to start my local TNS Listener service, OracleOraDb10g_home1TNSListener, I would get an error like this.

The OracleOraDb10g_home1TNSListener service on Local Computer started and then stopped. Some services stop automatically if they have no work to do, for example, the Performance Logs and Alerts service.

This forum thread, Can’t start Oracle service, suggested I do the following to diagnose the problem.

1. cmd
2. lsnrctl
3. start

This worked and I saw the following error which showed my Oracle install had not been properly done, the listener was pointing to the wrong server.

LSNRCTL> start
System parameter file is
  C:\oracle\product\10.2.0\db_1\network\admin\listener.ora
Error listening on:
  (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=bad.betweengo.com)(PORT=1521)))
TNS-12545: Connect failed because target host or object does not exist
 TNS-12560: TNS:protocol adapter error
  TNS-00515: Connect failed because target host or object does not exist
    32-bit Windows Error: 1004: Unknown error

In C:\oracle\product\10.2.0\db_1\network\admin\listener.ora the listener is improperly configured for bad.betweengo.com.

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = bad.betweengo.com)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
    )
  )

I ran Oracle’s Net Configuration Assistant and updated the Listener configuration which fixed the above listener to point to my server. Now C:\oracle\product\10.2.0\db_1\network\admin\listener.ora points correctly to good.betweengo.com.

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = good.betweengo.com)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
    )
  )

Sometimes I am faced with a situation where I need to know the source for a view or a procedure or a function. Fortunately Oracle stores the source in the database.

First I check to see what kind of object whose source I need is.

SQL> select object_name,object_type,status from user_objects where object_name = 'FOO';

If the object is a table I can simply recreate the table by doing a desc on that object.

SQL> desc FOO;

If the object is a function or stored procedure you can find its source in the user_source table.

SQL> select text from user_source where name = 'FOO' order by line;

If the object is a view you can find its source in the user_views table.

SQL> select text from user_views where view_name = 'FOO';

If the output seems to be truncated it is because text is of type LONG which is a big binary field. To allow more output do this.

SQL> set long 4000

Thanks to this article and this forum for helping me figure this out.

SQL> select privilege from user_tab_privs where lower(table_name)=’t_foo’ and lower(grantee)=’frank’;

PRIVILEGE
—————————————-
UPDATE
SELECT
INSERT
DELETE

SQL> select * from user_role_privs;

USERNAME GRANTED_ROLE ADM DEF OS_
—————————— —————————— — — —
FRANK AQ_ADMINISTRATOR_ROLE NO YES NO
PUBLIC SELECT_CATALOG_ROLE NO YES NO

To insert a text value with an ampersand, e.g. AT&T, one can do something like this.

insert into foo values(‘AT’||Chr(38)||’T’)

To learn more see How does one disable interactive prompting in SQL*Plus?

To insert a text value with a single quote, e.g. Don’t do it, one can do something like this.

insert into foo values(‘Don”t do it’)

To learn more see How does one escape special characters when building SQL queries?