SQL> 
SQL> --register schema
SQL> begin
  2  dbms_xmlschema.deleteSchema('http://www.example.com/schemas/ipo.xsd',4);
  3  end;
  4  /

PL/SQL procedure successfully completed.

SQL> begin
  2  dbms_xmlschema.registerSchema('http://www.example.com/schemas/ipo.xsd',
  3  '<schema targetNamespace="http://www.example.com/IPO"
  4           xmlns="http://www.w3.org/2001/XMLSchema"
  5           xmlns:ipo="http://www.example.com/IPO">
  6    <annotation>
  7     <documentation xml:lang="en">
  8      International Purchase order schema for Example.com
  9      Copyright 2000 Example.com. All rights reserved.
 10     </documentation>
 11    </annotation>
 12    <element name="purchaseOrder" type="ipo:PurchaseOrderType"/>
 13    <element name="comment" type="string"/>
 14    <complexType name="PurchaseOrderType">
 15     <sequence>
 16      <element name="shipTo"     type="ipo:Address"/>
 17      <element name="billTo"     type="ipo:Address"/>
 18      <element ref="ipo:comment" minOccurs="0"/>
 19      <element name="items"      type="ipo:Items"/>
 20     </sequence>
 21     <attribute name="orderDate" type="date"/>
 22    </complexType>
 23    <complexType name="Items">
 24     <sequence>
 25      <element name="item" minOccurs="0" maxOccurs="unbounded">
 26       <complexType>
 27        <sequence>
 28         <element name="productName" type="string"/>
 29         <element name="quantity">
 30          <simpleType>
 31           <restriction base="positiveInteger">
 32            <maxExclusive value="100"/>
 33           </restriction>
 34          </simpleType>
 35         </element>
 36         <element name="USPrice"    type="decimal"/>
 37         <element ref="ipo:comment" minOccurs="0"/>
 38         <element name="shipDate"   type="date" minOccurs="0"/>
 39        </sequence>
 40        <attribute name="partNum" type="ipo:SKU" use="required"/>
 41       </complexType>
 42      </element>
 43     </sequence>
 44    </complexType>
 45    <complexType name="Address">
 46     <sequence>
 47      <element name="name"    type="string"/>
 48      <element name="street"  type="string"/>
 49      <element name="city"    type="string"/>
 50      <element name="state"   type="string"/>
 51      <element name="country" type="string"/>
 52      <element name="zip"     type="string"/>
 53     </sequence>
 54    </complexType>
 55    <simpleType name="SKU">
 56     <restriction base="string">
 57      <pattern value="\d{3}-[A-Z]{2}"/>
 58     </restriction>
 59    </simpleType>
 60  </schema>',
 61     TRUE, TRUE, FALSE);
 62  end;
 63  /

PL/SQL procedure successfully completed.

SQL> 
SQL> -- create table to hold XML instance documents
SQL> DROP TABLE po_tab;

Table dropped.

SQL> CREATE TABLE po_tab (id number, xmlcol xmltype)
  2   XMLTYPE COLUMN xmlcol
  3   XMLSCHEMA "http://www.example.com/schemas/ipo.xsd"
  4   ELEMENT "purchaseOrder";

Table created.

SQL> 
SQL> desc po_tab
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 ID                                                 NUMBER
 XMLCOL                                             SYS.XMLTYPE(XMLSchema "http:
                                                    //www.example.com/schemas/ip
                                                    o.xsd" Element "purchaseOrde
                                                    r") STORAGE Object-relationa
                                                    l TYPE "PurchaseOrderType82_
                                                    T"

SQL> 
SQL> INSERT INTO po_tab VALUES(1, xmltype(
  2  '<?xml version="1.0"?>
  3  <ipo:purchaseOrder
  4    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  5    xmlns:ipo="http://www.example.com/IPO"
  6    xsi:schemaLocation="http://www.example.com/IPO
  7                           http://www.example.com/schemas/ipo.xsd"
  8    orderDate="1999-12-01">
  9      <shipTo xsi:type="ipo:Address">
 10          <name>Helen Zoe</name>
 11          <street>121 Broadway</street>
 12          <city>Cardiff</city>
 13          <state>Wales</state>
 14          <country>UK</country>
 15          <zip>CF2 1QJ</zip>
 16      </shipTo>
 17      <billTo xsi:type="ipo:Address">
 18          <name>Robert Smith</name>
 19          <street>8 Oak Avenue</street>
 20          <city>Old Town</city>
 21          <state>CA</state>
 22          <country>US</country>
 23          <zip>95819</zip>
 24      </billTo>
 25      <items>
 26          <item partNum="833-AA">
 27              <productName>Lapis necklace</productName>
 28              <quantity>1</quantity>
 29              <USPrice>99.95</USPrice>
 30              <ipo:comment>Want this for the holidays!</ipo:comment>
 31              <shipDate>1999-12-05</shipDate>
 32          </item>
 33      </items>
 34  </ipo:purchaseOrder>'));

1 row created.

SQL> declare
  2    xmldoc xmltype;
  3    begin
  4    select xmlcol into xmldoc from po_tab p;
  5    --   select value(p) into xmldoc from po_tab p;
  6    --   validate against XML schema
  7    xmldoc.schemavalidate();
  8  
  9    if xmldoc.isschemavalidated() = 1 then
 10                        dbms_output.put_line('Data is valid');
 11    else
 12                        dbms_output.put_line('Data is invalid');
 13    end if;
 14  end;
 15  /
Data is valid                                                                   

PL/SQL procedure successfully completed.

SQL> spool off