Oracle Plsql Troubleshooting When performing update or delete

Oracle Plsql has encountered a plsql when executing update or delete, or is causing the code to execute SQL when it dies.

When encountering this problem in development, the SQL was originally copied out, executed in Plsql, the SQL itself is spelled correctly, but there is the case that Plsql is dead,

In the code, where the execution of the SQL breaks the point debug, the discovery executes SQL, and still no response. After searching the information on the Internet, I guess the cause of this situation is

 there may be no commit,oracle to lock the record when Plsql developer executes the update.
Can be resolved by the following methods:search for locked records firstSQL codeSELECT S.sid, s.serial# from V$locked_object Lo, dba_objects ao, v$session s WHERE ao.object_id = lo.object_id and lo.  session_id = S.sid;  and then delete the locked record .SQL code

ALTER System KILL Session ' sid,serial# ';

Through the above SQL, the problem finally solved!

Summed up the hope for everyone to develop a help!