title: Defining size of tables without data (Oracle)
body: <p>My problem is a little bit complicated, so please bear with me when I try to explain it ^_^.</p>
  
  <p>I work on automatically generating several (a big number) DW snowFlake schemas, from a star schema input. In the other hand, i have a set of queries, that change according to the schema of course.</p>
  
  <p>My purpose is to calculate the cost model of each query on each schema, knowing that I have only statistics about table sizes, row sizes, page sytem sizes, etc (all the parameters needed to calculate the cost model). if there would be data, I could use the "explan plan of the dbms" to generate  the "best" plan of each query in order to calculate the cost model, and this will save me a lot of time :) </p>
  
  <p>But unfortunately, I have no data, and I wonder if I could use the "explain plan", just by setting the parameters without data, in other words, defining size of tables without data. Is it possible on Oracle, or any other DBMS??</p>
  
  <p>Thanks in advance.</p>
  
  <p>P.S : i could just ask the question : "Can i set the size of tables in oracle (or any other DBMS) (without having data), but i prefered to explain the whole problem, hoping that i'll have alternative proposals.</p>