For example:

Suppose you just create a new user called test1.
Then test1 logins and tries to create a simple table called t1.

But as the user does not yet have privilege to create an object (even in his own schema),
the error ORA-01031: insufficient privileges will be encountered.

[oracle@HOST1 ~]$ sqlplus / as sysdba

SQL> create user test1 identified by test1;

User created.

SQL> grant connect to test1;

Grant succeeded.

SQL> exit

[oracle@HOST1 ~]$ sqlplus test1/test1

SQL*Plus: Release 11.1.0.7.0 – Production on Wed Jan 19 12:47:45 2011

Copyright (c) 1982, 2008, Oracle.  All rights reserved.

Connected to:
Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 – 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> create table t1(num number);
create table t1(num number)
*
ERROR at line 1:
ORA-01031: insufficient privileges

SQL> exit;

Solution:

Grant appropriate privilege to the user.

[oracle@HOST1 ~]$ sqlplus / as sysdba

SQL> grant resource to test1;

SQL>  create table t1(num number);

Table created.

SQL> drop table t1;

Table dropped.

SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 – 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
[oracle@HOST1 ~]$

Actions to take: Make sure that the table or view or synonym that you are referencing exists in the database and ensure they have necessary privileges.

For example if you try to access a table or view from another schema and you do not have select privilege to that table or view then you will get this error message. Even if you specify the table or view name using the schema name- you will still get this error.

Lets’ say there is a table called table1 in a schema called schema1. There is another schema called schema2. At the moment you are in Oracle schema2 and want to execute an Oracle select statement on table1 such as

select * from schema1.table;

But if you do not have Oracle select privilege granted to you then you will get ORA-00942.

To fix that login to Oracle in your schema1 schema and then run the following statement to grant select privilege to schema2.

SQL> grant select on schema1.table1 to schema2;

Now you should be able to access table1 data from schema2 as long as you qualify the Oracle table name with the schema name i.e. schema1.table1. This query should return you data now.

select * from schema1.table;

However you may find that specifying the schema name of the table owner each time is quite problematic/time consuming – i.e. the schema name is not easy to spell or quite long. In that case you can to use Oracle synonyms.

Creating an Oracle synonym allows you to specify the name of an Oracle object from another Oracle schema as if they are in your current schema.

To know how it works / see example Click here for Oracle Synonym examples

I hope this post helped. Please leave your comments below.

Today I encountered an error in my oracle database which displays the error ORA-01552: cannot use system rollback.

I do not recollect experiencing this error before.

Investigation:

So I went to Google looking for an answer. In most of the posts in various forums the recommendation is

1. To create rollback segments

2. To make existing rollback segments online.

So I suspected my rollback segments are offline. But when I run the query

select segment_name, owner, tablespace_name, status from dba_rollback_segs;

I found that all the rollabck segments online and there are 6 rollback segments in my database. So it can not be the offline  rollback segment. Also as I have 6 rollback segments I don’t need any extra rollback segments anymore.

Then I questioned myself:  is there enough space in the tablespace used for the rollback segments. After running the query:

SELECT tablespace_name, sum((bytes/1024)/1024) free FROM DBA_FREE_SPACE group by tablespace_name;

Solutions:

What I found is that the tablespace used for rollback segments have only 4M free space left. Considering the number of transactions that were running on the database – I felt like this is not enough, so I increased the size of the tablespace by running the commands (to increase datafile size):

ALTER DATABASE DATAFILE ‘/u01/oradata/datafile/ora_rollback_db1.dbf’ RESIZE 500M;

Then I tried again and I still keep getting ORA-01552: cannot use system rollback error. So the change did not take effect on the fly.

Then I restarted Oracle database. This time it is gone.

So – what I learned is that, it is not always just the non existence of rollback segments or offline rollback segments that could cause this error to occur. In this case I found that the error occurred because there was not enough space on the tablespace where rollback segments are based.

I hope this will help readers to understand this defect a bit more clearly.

If you like this post or just want to add more on the defect please leave your comment.

Example 1:

declare
l_fname varchar2(3);
begin
l_fname := ‘abcd’;
end;
/
declare
*
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error
ORA-06512: at line 4

Notice here that the actual error occurred is actually ORA-065 02. But the 2nd error code ORA-06512 helps us to understand/locate the exact location where the error occurred.

Example 2:

Create three stored procedure as

create or replace procedure p_test11(p_empno number, p_sal number)
is
begin
p_test22(11,10);
end;
/

create or replace procedure p_test22(p_empno number, p_sal number)
is
begin
p_test33(p_empno, p_sal);
end;
/

create or replace procedure p_test33(p_empno number, p_sal number)
is
l_num number;
l_num2 number;
l_num3 number;
begin
null;
l_num := p_empno;
l_num2 := p_sal;
l_num3 := ‘abc’;
end;
/

Note that the stored procedure p_test33 has got an error condition at line 10, we are assigning characters to a numeric field. But the stored procedure compile happily as we don’t check the validity of pl/sql statements at this point.

Now when you call p_test11 with correct parameters you will get this error:

SQL> exec p_test11(1,2);
begin p_test11(1,2); end;

*
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error
ORA-06512: at “TPASS.P_TEST33″, line 10
ORA-06512: at “TPASS.P_TEST22″, line 4
ORA-06512: at “TPASS.P_TEST11″, line 4
ORA-06512: at line 1

Notice the ORA-06512, it is correctly identifying exactly where the errors are occurring.

How to Fix:

identify the line number and the root error code ( in this case ORA-06502: PL/SQL: numeric or value error)

and fix the prolem.

Learn more on ORA-06502: PL/SQL: numeric or value error

Example 1:

declare
l_name varchar2(3);
begin
l_name := ‘abcd’ ;
end;
/

declare
*
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error
ORA-06512: at line

Explanation: ORA-06502 occurred at line  4 because the variable l_name is defined as varchar2(3). But at line 4 we am assigning a value which is four character long ( larger than the variable can accommodate). That’s why the error is encountered.

Example 2: Iin a stored procedure

create or replace procedure p_test(p_empno number, p_sal number)
is
begin
null;
end;
/

Now called the stored procedure as

SQL> exec p_test(‘abc’, 200);

You will get the following output

begin p_test(‘abc’, 200); end;

*
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error
ORA-06512: at line 1

Explanation: the stored procedure p_test is expecting two parameters both of which are numeric types. But while calling the procedure I am passing a character value. The pl/sql engine can not convert characters to numbers so it returns ORA-06512.

How to Fix:

This problem can be fixed by changing the data type or by passing correct type of data.