If I try to return a ResultSet the class will not compile with the message that boolean cannot be converted to a ResultSet. And this is in synch with the documentation that states the "exists" subquery will return a boolean -- not a ResultSet.
There are a number of sites that indicate the statement is the way to find out if a table exists. Are the sites for an older version of PG? I'm running on 10.
Thanks.
On Sun, Jun 10, 2018 at 1:44 PM, David G. Johnston <david.g.johnston@gmail.com> wrote: > On Sunday, June 10, 2018, Chuck Davis <cjgunzel@gmail.com> wrote: >> >> >> try { >> result = stat.execute("select exists (select 1 from >> information_schema.tables where table_name = 'entities')"); >> System.out.println("the checkEntity returned a result of " >> + result); >> } catch (SQLException ex) { >> >> Logger.getLogger(ClientConstants.class.getName()).log(Level.SEVERE, >> null, ex); >> result = false; >> return result; >> } > > > Your query is putting "false" into cell (0,0) of a ResultSet. You are > failing to even look at the resultset to see if it holds a true or false. > > The query should never fail since you aren't using the table name directly > but are checking for it as a value in another table that always exists. The > inner query returns zero records when the table doesn't exist and the EXISTS > construct converts that to false. > > David J. >
