Schema restrictions on objects and instances

[Victor (5)]

I have a Schema with some elements which are "types" or objects, and some elements which correspond to instances of the types. How can I specify that a <locationInstance> must have an attribute "type" which equals any one of the "id" attributes of the <locationType>s?

 

[Martin Honnen]

I have a Schema with some elements which are "types" or objects, and some elements which correspond to instances of the types. How can I specify that a <locationInstance> must have an attribute "type" which equals any one of the "id" attributes of the <locationType>s?

Have a look at ID/IDREF and key/keyref.

 

[Victor (5)]

Have a look at ID/IDREF and key/keyref.

Thanks!

After a lot of looking around for working and well-explained examples, I managed to get the following (in case someone is looking for something similar):

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <xsd:element name="ImportData"> <xsd:complexType> <xsd:sequence> .. definitions of the "locationType" and "location" elements .. </xsd:sequence> </xsd:complexType>

<xsd:key name="locationTypeId">
<xsd:annotation>
<xsd:documentation>Within the whole data set, every location type must have a unique ID attribute</xsd:documentation> </xsd:annotation> <xsd:selector xpath=".//locationType"/> <xsd:field xpath="@id"/> </xsd:key>

<xsd:key name="locationId">
<xsd:annotation>
<xsd:documentation>Within the whole data set, every location must have a unique ID attribute</xsd:documentation> </xsd:annotation> <xsd:selector xpath=".//location"/> <xsd:field xpath="@id"/> </xsd:key>

<xsd:keyref name="locationIdRef" refer="locationTypeId"> <xsd:annotation> <xsd:documentation>Locations must be of an existing locationType</xsd:documentation> </xsd:annotation> <xsd:selector xpath=".//location"/> <xsd:field xpath="@type"/> </xsd:keyref>

.... The rest of the Schema ...

A few notes:

- <key> is basically the same as <unique>, except that the elements and/or attributes referenced in the <field> XPath _has_ to exist, i.e.
they cannot be empty.