title: Update SQL tables using PK-less data from Excel spreadsheet
body: <p><strong>Background</strong></p>
  
  <p>I have an app that (using typescript) has already inserted Excel data into a SQL db. All tables have PKs that are set up when populating the excel data. It's basically going from a Primary Keyless flatfile db, to a 3 table relational db, so the data is being separated among the tables.</p>
  
  <p>Unfortunately, the excel spreadsheet can't be thrown away so we can just update data using only the app, because it is updated daily and the app must grab from it to update the rows for the respective tables. (This is an experiment, I know it's not the best way of doing this).</p>
  
  <p>The only table that doesn't have anything that needs updating is the first table, but the second and third tables do. </p>
  
  <p>One thing that stumps me is the fact that one of the columns (belonging to the third table) that is a strong identifier (isn't unique, but close) that I place in one of the tables can have missing data one day, then pop up the next.</p>
  
  <p><strong>Question</strong></p>
  
  <p>In this scenario...</p>
  
  <ul>
  <li>If a change occurs to a row in the excel spreadsheet that was already inserted into the db, how can I detect that change without a primary key? Any workarounds people have done in past situations?</li>
  </ul>