title: How to update all collection in firebase firestore in flutter
body: <p>I have two collections. One collection &quot;User&quot;, who contains the user info (name...) And one collection &quot;Post&quot; who contains all posts of my flutter application. A post document contains many fields like a &quot;Title&quot;, &quot;Name&quot; of the user. I add an option in my application to allow the user to change his name. But I must change the name in the &quot;User&quot; collection and in all posts it creates in the &quot;Post&quot; collection. How should I do it? Can anyone help me with an example?</p>