Regex - Matching Strings with a Single Character -

i'm new regex. i'm looking expression return results meet following criteria:

the first word must 3 letters or more
the last word must 3 characters or more
if word or words in-between first , last word contains 1 letter, return phrase
every other word in-between first , last character (apart single letter words) must 3 letters or more

i return phrases like:

'therefore a hurricane shall arrive' , 'however i know i michael smith'

there should space between each word.

so far have:

^([a-za-z]{3,})*$( [a-za-z])*$( [a-za-z]{3,})*$

any appreciated. spacing? i'm using application called 'oracle edq'.

in normal regex world you'd use \b, word boundary.

^[a-za-z]{3,}(\s+|\b([a-za-z]|[a-za-z]{3,})\b)*\s+[a-za-z]{3,}$                   ^^                       ^^

and perhaps, non-capturing groups (as anubhava shows).

from see, there no word boundaries in oracle edq regex syntax (as non-capturing groups). should rely on \s pattern, matching whitespace.

so, make obligatory, either with

^[a-za-z]{3,}(\s+|\s([a-za-z]|[a-za-z]{3,}))*\s+[a-za-z]{3,}$                   ^^

^[a-za-z]{3,}(\s+|([a-za-z]|[a-za-z]{3,})\s)*\s*[a-za-z]{3,}$                                          ^^    ^

Stadnd