Bookshelf v7.5: XML Schema, IAA-XML, and IFX Data Types

The W3C committee is defining a schema to be used for XML message definition and validation. One of the advantages of using the XML schema over DTDs is the ability to use and validate data types. The schema implementation is not yet available, however, forcing the first implementation of IAA-XML to use DTDs.

Siebel System has examined the XML schema draft specification of data types, found at http://www.w3c.org/TR/2000/WD-xmlschema-2-20000225, and compared them with the IFX data types, as shown in Table 28.

Table 28. XML Schema Draft Specification Comparison
IAA-XML Data Types	IFX Data Type	XML Schema Primitive Data Type
String	Character	String
Text
Not supported	Narrow Character	String with a length attribute specified
Binary	Binary	Binary
Boolean	Boolean	Boolean
Not supported	YrMon	TimeInstant with the with the day, hour, minute, and second omitted
Date	Date	TimeInstant with the hour, minute, and second omitted
Time	Time	TimeInstant with the year, month, and day omitted
Not supported	DateTime	TimeInstant with seconds expressed as integers
Timestamp	Timestamp	TimeInstant with decimal values included in seconds
Amount
Currency	Amount Currency	Amount Not supported
Not supported	Closed Enum	Supported by enumeration attribute of each data type
Enumeration	Open Enum	Supported by enumeration attribute of each data type
Short	Long	Supported by length attribute on decimal, with scale attribute of 0
Identifier	Identifier	ID
Not supported	Phone Number	Not supported
Decimal	Decimal	Decimal
Not supported	Universally Unique Identifier (UUID)	Not supported
Not supported	URL	URI-reference

XML schema has additional primitive data types for float (floating point number), double (double precision floating point number), TimeInstant, TimeDuration, RecurringInstant, IDREF (like IDREF in DTDs), ENTITY (like ENTITY in DTDs), and NOTATION (like NOTATION in DTDs). In addition, XML schema has derived data types that are specializations of primitive data types, such as language, integer, date, time, and name. In addition it supports user-defined data types.

Furthermore, the date and time formats for IFX, although functionally equivalent, are implemented differently. The IFX timestamp specification is the same as the XML schema format. If IAA-XML users choose to implement IFX conventions for other date and time formats in adapters, those adapters will have to change when XML schema has been adopted. Except for timestamp, IAA-XML DTDs will not use the IFX date and time data types at this time; they are defined only for consistency.