Hi Kazuaki, Firstly, be real careful about using SQL taglibs. It very much goes against the patterns discussed in class for the reasons discussed in class.
However, taglibs aside, I understand your concern. The main reason is that the ResultSet can start getting processed immediately under some conditions, thus it makes sense not to know the final number of records because the database might not have counted the final number of records. A corollary from that is that UI often only displays a certain number of records and only wants a few at a time, so we can often go a step further and use the LIMIT qualifier (available in many sql implementations for that purpose). The good news about the "SELECT COUNT(id)" syntax is that you don't need ordering, and you're usually selecting on an index, even if not the primary one, so it can do those counts pretty darn fast. The count may also prime the next initial select query, on a good db. On Wed, Sep 24, 2014 at 4:52 AM, Kazuaki Miyauchi <miyau...@gmail.com> wrote: > Hi, it seems there is no way to get the numbers of records without > issuing count sql . It is convenient to get the number as following. > > <sql:query var="rsSelect" dataSource="${example}" sql="select > firstName, address from member where id = 'aiueo';" /> > <c:if test="${rsSelect.countNum == 0}" > > ... > > Why is there no function to get record number? > > Regards, > > --------------------------------------------------------------------- > To unsubscribe, e-mail: taglibs-user-unsubscr...@tomcat.apache.org > For additional commands, e-mail: taglibs-user-h...@tomcat.apache.org > -- Stuart Thiel, P. Eng. --------------------------------------------------------------------- To unsubscribe, e-mail: taglibs-user-unsubscr...@tomcat.apache.org For additional commands, e-mail: taglibs-user-h...@tomcat.apache.org