Daily Archives: March 2, 2012

Friday Fixes

It’s Friday, and time again for some Friday Fixes: selected problems I encountered during the week and their solutions.

CSS – Space Matters

Guess you could say I was “lost in [a] space” wondering why my browser didn’t pick up my div’s CSS class.  Turns out, I wrote the selector as #myid .myclass (descendent selector) but really meant #myid.myclass (combined selector). Thank you, 2.5x reading glasses and Chris Coyier, for the quick save.

Point of No Return

JavaScript and jQuery iterator functions are awfully convenient, but it’s easy to overlook scope.  While refactoring some code today, I wrapped a function around some iterator code for reuse and broke it. Here’s a simplified example to demonstrate the problem:

     function myFunction() {
        $.each(['a', 'b', 'c'], function(idx, ea) {
           if (ea === 'b') {
              return ea;
           }
        });
     }

At a glance, you’d think myFunction returns b, but since the inner function’s result is never passed out, it returns undefined.  And jQuery’s each method just returns the collection, so adding a return in front doesn’t help.  jQuery does have some alternatives (like filter) that can help, but those aren’t as flexible as each.

The simple solution is to just carry the value to the outer scope, like so:

     function myFunction() {
        var result;
        $.each(['a', 'b', 'c'], function(idx, ea) {
           if (ea === 'b') {
              result = ea;
              return false;
           }
        });
        return result;
     }

Adding the “return false” stops the iteration at the first match.

Is this Thing Used?

My current project has this DB2 LUW fan coding against a DB2 for z/OS database.  While I give up a some things, I also gain a lot.  For example, while working on a DAO, I had questions about a particular table’s indexes.  Fortunately, DB2 for z/OS has SYSINDEXPLANSTATS which, among other things, keeps track of the last time an index was used (even for dynamic SQL) to help determine its merits.  So I first checked to see if this was at least version 9:

select getvariable('SYSIBM.VERSION') from sysibm.sysdummy1;

… and then answered my questions with a simple query like the following:

select i.name, i.tbname, i.creator, i.uniquerule, i.colcount, i.clustering, s.lastused
from sysibm.sysindexes i, sysibm.sysindexspacestats s
where i.name = s.name
and i.creator = s.creator
and i.dbname = 'MYDB'
and i.tbname like 'MYPREF%'
order by s.lastused

Can’t wait for this to make its way to DB2 LUW.

VSSibility

Yes, I presently have to use Microsoft Visual SourceSafe (VSS).  I’m over it now.  When using this “lock first” VCS against a deep project hierarchy, I often need to see a quick list of my check-outs.  I can use View->Search->Status Search (with subprojects selected) from the VSS GUI, but that’s often too slow over a remote VPN connection.  So I cooked up a quick script to run over an ssh command line from a server that is “local” to the repository:

cd /d "C:\Program Files\Microsoft Visual SourceSafe"
set SSDIR=\\myserver\VSS\myvssshare
ss STATUS $/MyProject -R -Umyusername

Flexigrid Echo

Imitation isn’t always flattering; it’s often annoying.  Having two Flexigrids on one page, both with pagers enabled (usepager: true) yielded some weird mocking behavior.  For example, paging forward on one grid caused both grids to show the same “Page X of Y” message.  After debugging, I found that similar bugs had been reported and fixed in the latest release.  Upgrading Flexigrid resolved that one.