title: MS SQL creating many-to-many relation with a junction table
body: <p>I'm using Microsoft SQL Server Management Studio and while creating a junction table should I create an ID column for the junction table, if so should I also make it the primary key and identity column? Or just keep 2 columns for the tables I'm joining in the many-to-many relation?</p>
  
  <p>For example if this would be the many-to many tables:</p>
  
  <pre><code>MOVIE
  Movie_ID
  Name
  etc...
  
  CATEGORY
  Category_ID
  Name
  etc...
  </code></pre>
  
  <p>Should I make the junction table: </p>
  
  <pre><code>MOVIE_CATEGORY_JUNCTION
  Movie_ID
  Category_ID
  Movie_Category_Junction_ID
  </code></pre>
  
  <p>[and make the <code>Movie_Category_Junction_ID</code> my Primary Key and use it as the Identity Column] ?</p>
  
  <p>Or:</p>
  
  <pre><code>MOVIE_CATEGORY_JUNCTION
  Movie_ID
  Category_ID
  </code></pre>
  
  <p>[and just leave it at that with no primary key or identity table] ? </p>