title: Does MySQL support check constraint?
body: <p>Does MySQL support check constraint?</p>
  
  <p>I am able to execute the following script in MySQL without error.</p>
  
  <pre><code>ALTER TABLE  EMP_DB_DESIGN_EXCEL  ADD (
     CONSTRAINT CHK_EMP_IS_ACTIVE CHECK (IS_ACTIVE IN ('Y','N')));
  </code></pre>
  
  <p>But it is not reflected if I query:</p>
  
  <pre><code> SELECT * FROM information_schema.TABLE_CONSTRAINTS T where t.table_name='EMP_DB_DESIGN_EXCEL';
  </code></pre>