ORA-00001: Unique constraint (string.string) violated explained & solution

Code: ORA-00001

Description: Unique constraint (string.string) violated

Causes:

  • A DML command like UPDATE, INSERT attempt to insert duplicated keys
  • A trigger trying to insert/update duplicated keys

Solutions:

  • Abort update/insert the key
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How to create bootable Ubuntu USB from ISO file in Windows

To install Ubuntu/Lubuntu or many Linux distros from USB stick, in this post, I will show you how to create bootable Ubuntu USB from ISO file.

Step 1: Download the ISO file

For Ubuntu server, you can go to https://www.ubuntu.com/download/server and download desired version of … Read the rest “How to create bootable Ubuntu USB from ISO file in Windows”

How to start Oracle database ignore missing datafile(s)

Some of database datafiles are damaged or corrupted or moved to another position without modifying datafile name or datafiles are missing, … and now we need to startup the Oracle database ignoring missing datafiles.

Situation

In this case, assume that we miss

'/u01/oracle/oradata/oraerr.com/data01.dbf'

We’ll got … Read the rest “How to start Oracle database ignore missing datafile(s)”

How to start & stop Oracle databases (startup & shutdown)

In this post, I will show you all commands to start and stop Oracle databases. This is the basics but essentials while working with Oracle.

startup:

Login into database server, switch to oracle user and start sqlplus tool

su - oracle
sqlplus / as sysdba
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