What is "key" element good for?

ko5tik · **Posted:** Thu Dec 04, 2003 12:56 pm

Hi all,
while lookin deeply into mapping DTD, it seems strange to me that <key/> is needed.

It has only 2 implied properties, which could be elements of parent
tag...

( do not wonder, I'm just rewriting xdoclet 2 template :) )

emmanuel · **Posted:** Thu Dec 04, 2003 1:14 pm

Key can contain column element

ko5tik · **Posted:** Thu Dec 04, 2003 1:24 pm

epbernard wrote:

Key can contain column element

More than one? For example for composite IDs?

emmanuel · **Posted:** Thu Dec 04, 2003 1:50 pm

Yep,

Code:

<class name="eg.Foo">
    ....
    ....
    <set name="dates" lazy="true">
        <key>   <!-- a collection inherits the composite key type -->
            <column name="foo_string"/>
            <column name="foo_short"/>
            <column name="foo_date"/>
        </key>
        <element column="foo_date" type="date"/>
    </set>
</class>

same for subclasses.