CODEWITHSUNDEEP
joinxsd
David Thielen
David Thielen

Reputation: 32926

Can you do a "join" in an XML schema

I'm pretty sure the answer to this is no but it never hurts to ask. Is there a way to do a join in an XML schema?

Here's what I mean. You can have employees/employee/@office_id and elsewhere in the xml have /offices/region/office/@office_id. Is there a way in the schema to tell it that these two attributes map to each other?

I ask because then we can automatically for an employee get their office info without requiring the user to specify this relationship.

Upvotes: 0

Views: 798

Answers (3)

LJB
LJB

Reputation: 1

External references and connections between XML entities can be specified with XLINK.

Upvotes: -2

T. Cowart
T. Cowart

Reputation: 65

Are you asking if you can set up a schema such that every employee/@office_id has a corresponding office/@office_id?

If you know the possible office ids you could create a type like so:

<xsd:simpleType name="OfficeIDType">
    <xsd:restriction base="xsd:integer"> <!-- or whatever type an office id is -->
        <xsd:enumeration value="1"/>
        <xsd:enumeration value="2"/>
        <xsd:enumeration value="3"/>
    </xsd:restriction>
</xsd:simpleType>

And then when declaring your attributes, make them this type and required, like so:

<xsd:attribute name="office_id" type="OfficeIDType" use="required"/>

Upvotes: 0

duffymo
duffymo

Reputation: 308763

JOIN is a relational concept. You'd have to code the equivalent in XPATH. I don't believe there's any mechanism to help you with it. You'll have to get the office instances and loop over them for a given individual's office, all in your code or XSLT.

Upvotes: 4

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