Greg Alvord
Senior Data Architect, RealEC
Chairman Architecture Committee
MISMO Trimester Meeting
January 23-27, 2012 Jacksonville, Florida

• Motivation
• W3C Schema
MISMO Trimester Meeting
January 23-27, 2012 Jacksonville, Florida

• Why Did MISMO switch from DTD to
Schema?
– W3C Schema did not exist when 2.X Started
• First goal of V3 was to use schema
– DTD does not have data typing
– Most Development tools use schema
MISMO Trimester Meeting
January 23-27, 2012 Jacksonville, Florida

• V2 Approach.
– Date is a string
– Implementation Guide states format
– Many developers never saw the IG Poorly formed date data huge drain on productivity.
• V3 Approach
– Xsd:date data type format same as V2 recommendation. (ISO 8601)
– Test by schema validation
MISMO Trimester Meeting
January 23-27, 2012 Jacksonville, Florida

• Why Should Developers Understand Schema?
– Schema is your specifications
• Structure
• Data Types
• Documentation
– If your code produces XML
• Test your output with schema
– If your code accepts XML
• Require schema valid input.
• Schema validate input
– Development
– Testing
MISMO Trimester Meeting
January 23-27, 2012 Jacksonville, Florida

• NEVER make or consume XML as string.
• Better to use an XML object in whatever library you are using.
– XML Objects usually have a serialized string property.
• Best to use data model object and serialize or de-serialize to XML.
– Use .NET XSD.exe to read schema write object model.
– Use other similar tools in other platforms.
MISMO Trimester Meeting
January 23-27, 2012 Jacksonville, Florida

• XSD Extension on published Schema files
• xsd: prefix in schema files.
• Most data in xsd:element
– Security attributes
– Connecting attributes
– Other attributes.
• XML Encryption
• XML Signature
MISMO Trimester Meeting
January 23-27, 2012 Jacksonville, Florida

• Namespace used
– Root file MISMO_3.2.0_B290.xsd
<xsd:schema xmlns="http://www.mismo.org/residential/2009/schemas" targetNamespace= http://www.mismo.org/residential/2009/schemas
• Chameleon – xsd:include files
– No target namespace
– No declared namespace
MISMO Trimester Meeting
January 23-27, 2012 Jacksonville, Florida

• Why does it look like a URL?
– URL is kind of URI
– http: Means we could, but have not yet, make a page available.
• Why does it contain 2009?
– Change Namespace with release
– Fixed Namespace (X)
MISMO Trimester Meeting
January 23-27, 2012 Jacksonville, Florida

• Some data in xsd:attributes
– //LOANS/LOAN/@SequenceNumber
– //LOANS/LOAN/@LoanRoleType
• SubjectLoan – The loan that is the object of the transaction, upon which the receiving business partner will take some action.
• RelatedLoan – A loan linked to the subject loan by virtue of being collateralized by the same property.
Examples include the loan being refinanced, or a
HELOC or other subordinate lien collateralized by the same property as the subject loan.
MISMO Trimester Meeting
January 23-27, 2012 Jacksonville, Florida

• xsd:sequence
• Defines order of element children
– Order counts
– Lexicographically ordered list
• Lexicographical order is called “Dictionary order”
Capitalizations and white space is ignored. “_” is treated like a space.
• xsd:choice
– Defines exclusive choice
– Comes before other elements
MISMO Trimester Meeting
January 23-27, 2012 Jacksonville, Florida