Set default Magento page layout to 3 columns

Is there a way to set all pages (catalog,product,cart,checkout,search) as having a 3-column layout in local.xml, instead of specifying layout for each block?

I tried the following code

<?xml version="1.0"?>
<layout version="0.1.0">
        <default>
                <reference name="root">
                        <action method=&开发者_如何学编程quot;setTemplate"><template>3columns.phtml</template></action>
                </reference>
        </default>
</layout>

It's not working; the log shows

2011-08-12T07:20:10+00:00 CRIT (2): Not valid template file:frontend\base\default\template\3columns.phtml

As far as your error message is concerned, you are trying to load a file that doesn't exist. The filename in the error message was a huge giveaway. The page layout files are in template/page/*.phtml, not template/*.phtml.

You need to change:

<action method="setTemplate"><template>3columns.phtml</template></action>

to..

<action method="setTemplate"><template>page/3columns.phtml</template></action>

You should override page.xml layout and change the root block template in the default handle.

Copy app/design/frontend/base/default/layout/page.xml to app/design/frontend/default/YOURTHEME/layout/page.xml

Do the appropriate changes there :

<default translate="label" module="page">
    <label>All Pages</label>
    <block type="page/html" name="root" output="toHtml" template="page/3columns.phtml">
        <!-- ... -->
    </block>
</default>