Dbi question

ruby-talk
1

Hello, I was wondering if there is an elegant way of seeing if a query
is empty in ruby-dbi. Thank you for your time.

2

Jacques wrote:

Hello, I was wondering if there is an elegant way of seeing if a query
is empty in ruby-dbi. Thank you for your time.

There are two solutions, both of which are not very elegant:

  • Use COUNT(*) in your SQL statement, to see how many rows are in the
    result. Then use select_one to get this number.

  • Call method fetch once. If it returns nil, the query was empty.

If you’re using the Postgres DBD, use:

sth = dbh.execute(query)
sth[‘pg_row_count’] # returns the number of rows in the result

Try method StatementHandle#rows, if it returns the number of rows in the
result set. But pay attention that if that’s the case, it’s not the correct
behaviour of that DBD.

Regards,

Michael