swift 3 – swift optionals

the best way to take care of the optionals mark variable in the swift,

var lotSelected: Int?

if let lot = lotSelected {

always use “if let” sentence to check then use the new constant.


parse-ruby-client installation on OS X

after following the official guide of parse-ruby-client,

gem install parse-ruby-client

I still got some complain like this

Snip20150310 6

here you go,
make you osx keep your env in even sudo,

sudo visudo

Snip20150310 5

setup your GEM_PATH and GEM_HOME

# check path first
gem env
# export them
export GEM_HOME="/Users/Nil/.gem/ruby/2.0.0"
export GEM_PATH="/Library/Ruby/Gems/2.0.0:/Users/Nil/.gem/ruby/2.0.0:/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/gems/2.0.0"

then, the most important,
and parse-ruby-client missing this in dependencies,
or says they assume everyone already did before,

gem install bundler

I thought I already did before… that’s why I spent some time to figure out…

ORA-03113 ERROR after shutdown abort(incomplete shutdown)

if you got error ORA-03114 like this

Snip20141228 1

you can simply try to fix by following commands
go to service.msc, restart the service of the instance
after restart the service.
should be able to get in by sqlplus as sysdba

shutdown abort

re-login sqlplus as sysdba

startup mount
recover database 
until time '2014-12-27 0:00:00'; -- TODAY's DATE
alter database open resetlogs;

that’s it!

good luck!