Re: Patch to add support of "IF NOT EXISTS" to others "CREATE" statements

<div dir="ltr">On 13 June 2013 04:30, Peter Eisentraut <span dir="ltr"><<a href="mailto:peter_e@gmx.net"
target="_blank">peter_e@gmx.net</a>></span>wrote:<br /><div class="gmail_extra"><div class="gmail_quote"><blockquote
class="gmail_quote"style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im"><span
style="color:rgb(34,34,34)">I'mwondering where "IF NOT EXISTS" and "OR REPLACE" will meet.</span><br
/></div></blockquote></div><br/></div><div class="gmail_extra">CREATE OR REPLACE (or ALTER / UPDATE ?) would definitely
beuseful for enums, where it would be nice if we could teach an ORM to generate DDL based on the current values of the
enumin code, and know that after the operation had completed, the database enum type matched the code enum type. I
don'tthink a sequence of ALTER TYPE ADD VALUE IF NOT EXISTS quite does the trick, as it doesn't guarantee that the db
enumis in the same order as the code enum, which may or may not be important. I'd expect a CREATE OR ALTER for enums to
raisean error if any of the elements were out of order.</div><div class="gmail_extra"><br /></div><div
class="gmail_extra">Currentlyto get to a known state for enums you have to write manual migration scripts, and while
thattends to be how I roll anyway, often when starting projects in rails / grails / hibernate etc people rely on db
schemasgenerated by the framework as it lets them prototype with less mucking around. It would be nice for those
frameworksto be able to generate enum types in a known state.</div><div class="gmail_extra"><br /></div><div
class="gmail_extra">Cheers</div><divclass="gmail_extra"><br /></div><div class="gmail_extra">Tom</div></div>