&gt;&gt; It sounds like alot of extra code to write.<p>What he&#x27;s saying is more about convention than writing code. For instance, instead of adding a column &quot;abc&quot; and doing:<p>foo.abc = 123;<p>they would do something like:<p>if (foo.abc) {
  foo.abc = 123;
}<p>make sure all tests pass, and then migrate the db.<p>If you&#x27;re asking about tools to migrate code, all popular languages have one. (I.e. django comes with one that&#x27;s already really good).