How to define check constraint in oracle?

@aniya.jaskolski 

In Oracle, a check constraint is a condition that must be met before a row is inserted or updated in a table.

To define a check constraint in Oracle, you can use the following syntax:

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ALTER TABLE table_name 
ADD CONSTRAINT constraint_name 
CHECK (condition);

For example, if you have a table named "employees" and you want to create a check constraint that ensures that the salary of an employee is greater than 0, you can use the following query:

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ALTER TABLE employees 
ADD CONSTRAINT check_salary 
CHECK (salary > 0);

This will create a check constraint named "check_salary" on the "employees" table that ensures that the "salary" column has a value greater than 0.