title: is there concept like fact and dimension in bigquery
body: <p>As we are planning to migrate the data from Teradata to google cloud(Bigquery).
  In Teradata we have key concepts like primary and foreign with help of this keys we are able to define relation between dimension and fact.</p>
  
  <p>Say for example I have 3 dimension tables  and one fact table as shown below.</p>
  
  <p>D1 D2 D3 </p>
  
  <p>F1</p>
  
  <p>with the help of keys or indexes in Teradata we can able to fetch the data from fact table.</p>
  
  <p>When coming to Bigquery we do not have any concept like keys or indexes then how we are going to 
  define relation between the  dimension and fact </p>
  
  <p>Note: If there are no primary keys or index concept how we are going to eliminate the duplicates </p>