ORACLE PL/SQL

ConstraintCommands.sql

-- Select constraint 
select * from all_constraints
where constraint_name = 'T_CUST_PASS_CK'

ListnerCommands.sql

-- To change lisetner port ..
SQLPLUS /NOLOG

At the SQL Command Line prompt, enter the following command:

CONNECT SYSTEM/password

--where password is the SYSTEM password that you set upon installation (Windows) or configuration (Linux) of Oracle Database XE.

At the SQL Command Line prompt, enter the following command:

EXEC DBMS_XDB.SETHTTPPORT(nnnn);

--where nnnn represents the new port number to use for HTTP connection requests. Be certain that you select a port number that is not already in use.

--For example, to use port number 8087 for HTTP connection requests, enter this command:

EXEC DBMS_XDB.SETHTTPPORT(8087);

--If the command is successful, the following message is displayed:

--PL/SQL procedure successfully completed.

UserCommands.sql

sqlplus /nolog
connect / as sysdba
Once connected, you can change the SYS password to something you know:
ALTER USER sys IDENTIFIED BY new_password;