Changing XML schema to "Oracle" XML schema

In order to have better control over the XMLschema (or types) which is registered in Oracle DB we have to make some changes to it.
First add a new namespace xmlns:xdb="http://xmlns.oracle.com/xdb", which is the Oracle-supplied XML DB namespace. This will let you use additional "features" in XML schema:
- xdb:SQLType
- xdb:SQLName
- xdb:SQLCollType
- xdb:maintainDOM
- xdb:maintainOrder
- ...
I only wrote the ones we will need in this post.

The SQLType, SQLName, SQLCollType is used to name types, elements and collections and to overide the names given in the xsd schema. I suggest you use uppercase characters (this way you will avoid using double quotes when reffering to the elements,type,... (e.g. "Person"."Id")).
The usege of this three atributes is recommended, because this way, the names of types don't get automaticaly generated and you can be sure the name stays the same, even if you reregister the schema.

The default value of maintainDom is true. It insures DOM fidelity. Document Object Model (DOM) fidelity is the concept of retaining the structure of a retrieved XML document, compared to the original XML document, for DOM traversals. DOM fidelity is needed to ensure the accuracy and integrity of XML documents stored in Oracle XML DB.
The default value automaticaly generates a SYS_XDBPD$ element where there is a complex type. This element is of type xdb.xdb$raw_list_t.

If the XML element is declared with attribute maxOccurs > 1, then it is mapped to a collection attribute in SQL. The collection could be a varray value (default) or nested table if the maintainOrder attribute is set to false.

If you will be using the registered schema for creating objects of generated types I suggest you set the value to false for both (maintainDom and maintainOrder). It will be easier to create and manipulate objects based on their types.

The schema from the first post would now look like this:

<?xml version="1.0" encoding="utf-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            xmlns:xdb="http://xmlns.oracle.com/xdb">
<xsd:element name="Id">
  <xsd:simpleType>
   <xsd:restriction base="xsd:integer"></xsd:restriction></xsd:simpleType>
</xsd:element>
<xsd:element name="FirstName">
  <xsd:simpleType>
   <xsd:restriction base="xsd:string"><xsd:maxLength value="35" /></xsd:restriction>
  </xsd:simpleType>
</xsd:element>
<xsd:element name="LastName">
  <xsd:simpleType>
   <xsd:restriction base="xsd:string"><xsd:maxLength value="35" /></xsd:restriction>
  </xsd:simpleType>
</xsd:element>
<xsd:element name="Person" xdb:SQLType="PERSON_T" xdb:maintainDOM="false" xdb:maintainOrder="false">
 <xsd:complexType>
   <xsd:sequence>
     <xsd:element ref="Id" xdb:SQLName="ID"/>
     <xsd:element ref="FirstName" xdb:SQLName="FIRSTNAME"/>
     <xsd:element ref="LastName" xdb:SQLName="LASTNAME"/>
   </xsd:sequence>
 </xsd:complexType>
</xsd:element>
<!-- MAIN ELEMENT -->
<xsd:element name="People" xdb:SQLType="PEOPLE_T" xdb:maintainDOM="false" xdb:maintainOrder="false">
 <xsd:complexType>
   <xsd:sequence>
     <xsd:element ref="Person" minOccurs="0" maxOccurs="unbounded" xdb:SQLCollType="PERSON_C" xdb:SQLName="PERSON"/>
   </xsd:sequence>
 </xsd:complexType>
</xsd:element>
</xsd:schema>

You can get more information here.