title: What is the difference between PRIMARY KEY and CONSTRAINT PRIMARY KEY?
body: <p>I'm using MySQL and I am wondering what the difference is between this:</p>
  
  <pre><code>CREATE TABLE Employees(
  E_Id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
  );
  </code></pre>
  
  <p>and:</p>
  
  <pre><code>CREATE TABLE EMPLOYEES(
  E_Id INT NOT NULL AUTO_INCREMENT,
  CONSTRAINT pk_Employee PRIMARY KEY(E_Id));
  </code></pre>
  
  <p>Are they the same? </p>