title: Comparing Databases and Inserting values
body: <p>I am working on databases and now I need some advice's from you guys..</p>
  
  <p>I have 2 databases with many rows and columns and these db's contain addresses of customers.
  Lets name the databases a A,B.</p>
  
  <p>Now the problem is I have to search the addresses of B in A using a primary key lets say email.</p>
  
  <p>If the address exist then its ok.
  Else we have to insert the address in to the other database.</p>
  
  <p>Please tell me how can we do this and which language we can use to do this??</p>
  
  <p>Thank you very much for your time to read my question.</p>