SHOW CHECKs
SHOW CHECKs table_name
This command displays all user-defined check constraints defined for a specific table.Unlike other show commands, there is no option to display a list of all check constraints in the database.You must always provide a table name as part of the command.
SQL> show check employee;
CONSTRAINT INTEG_30:
CHECK ( salary >= (SELECT min_salary FROM job WHERE
job.job_code = employee.job_code AND
job.job_grade = employee.job_grade AND
job.job_country = employee.job_country) AND
salary <= (SELECT max_salary FROM job WHERE
job.job_code = employee.job_code AND
job.job_grade = employee.job_grade AND
job.job_country = employee.job_country))