title: Is it ever practical to store primary keys of one table as text in another table?
body: <p>Imagine if we had millions of rows in Table A.</p>
  
  <p>For each large row (10+ columns) of Table A, we might have 20+ rows that are exact duplicates except for a singular column where we store an ID for Table B.</p>
  
  <p>Would it be more EFFICIENT and/or MEMORY SAVING to store in Table A, the ID's for Table B in a text field ---> "B_ID1|B_ID2|B_ID3" etc and then return this data client-side, parse it, and then send it out for the actual data from Table B.</p>
  
  <p>This is assuming we had 2+ million rows of unique data in Table A and if we stored that additional column outside the text field, we would add 2 Million*20+ Rows to that individual table with all that extra wasted space.</p>
  
  <p>Or am I very naive in my approach and understanding of SQL? I literally just started using it like a week ago and taught myself the basics for my app.</p>