Class 12_2 Oracle 11g: Alter Table Read Only

In today’s discussion, we will talk about the following.

• Alter table read only.

What is read only? Why we need to alter the table into read-only? These are some important question that comes into one’s mind.

As you know, you can alter the table as well as you can add, delete, and modify columns and their data types. However, today I’ll tell you that you can also convert the table in read-only mode. This read-only status of the table will disable the box (Object) from any modification of any record that is already available in the table.

Why we need to change table read only?

We usually do this cause we do not allow anyone to modify the information that we already have. Generally we do this for reporting tables.

Let’s make it more concrete by completing an example.

Examples:

ALTER TABLE SCOTT.EMP READ ONLY;

SELECT * FROM SCOTT.EMP;

UPDATE SCOTT.EMP SET SAL=1000 WHERE EMPNO=7369;

ALTER TABLE SCOTT.EMP READ WRITE;

First pick the table that you want to convert it into read-only. In our case we have chosen SCOTT.EMP3

ALTER TABLE SCOTT.EMP3 READ ONLY;

Note: Scott.emp3 is the table name you can replace with your table name.

ERROR at line 1:

ORA-12081: update operation not allowed on table “SCOTT”.”EMP3″

ERROR at line 1:

ORA-12081: update operation not allowed on table “SCOTT”.”EMP3″

In order to resolve this error or back table into read and write mode, you need to run the following query if you have privileges otherwise contact you DBA.

ALTER TABLE SCOTT.EMP3 READ WRITE;

Note: Scott.emp3 is a table name you can replace with your table name.

I hope today we have covered this Read only feature.