title: Optional relationship in SQL Server -- How to implement in SSMS Schema Designer
body: <p>I have two cases where I would like to set 'optional' relationship inside one table or between two tables.</p>
  
  <p>First:</p>
  
  <p><img src="https://i.stack.imgur.com/9nmwQ.png" alt="enter image description here"></p>
  
  <p>I want to set this relation as optional, in other words: there will be categories and subcategories in one table, so subcategory column is only optional. </p>
  
  <p>Second:</p>
  
  <p><img src="https://i.stack.imgur.com/J8mZF.png" alt="enter image description here"></p>
  
  <p>Here I want to make sure that House cannot exist without Member (mandatory relation), but Member can be without any House (optional relation).</p>
  
  <p>I don't have any experience with Microsoft SQL Server and I don't have idea how can I modify these relations.</p>
  
  <p>Here is the end result in Oracle diagram:</p>
  
  <p><img src="https://i.stack.imgur.com/Hiuga.png" alt="enter image description here"></p>