title: phpMyAdmin: what is the parameter null?
body: <p>I have a new question, this time about the parameter null in phpMyAdmin. </p>
  
  <p>I am creating a datebase where some registers must be "Not null" and anothers I guess that it doesn't matter since my work doesn't say anything, I mean, it not say Not Null but Null either.</p>
  
  <p>For example, table student:</p>
  
  <pre><code>id - Primary Key|Int|Not Null|Auto increment
  teacher_id - Int| Not Null
  age - Int ////What I should click here?? to click Null or not?  /////
  name - Varchar(30) | Not Null
  reg_date - Datetime ////What I should click here?? to click Null or not?  /////
  </code></pre>
  
  <p>So, when I created the DB, for some registers I didn't click the checkbox Null trying to say NOT NULL but I cliked the checkbox trying to say "nothing".</p>
  
  <p>The question is, what do you think that I should do with the parameters where my work doesn't say anything?</p>
  
  <p>Thank you very much!</p>