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
  • Turn off/modify the trigger
  • Remove the unique constraint

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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

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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 some console like this:

Database 
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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
startup;

shutdown immediate

Everytime you … Read the rest “How to start & stop Oracle databases (startup & shutdown)”