XHTML DTD and XML Schema
By Mark Gleason - Web Developer at Xapsis Integrated Marketing
Coming from a guy that is
completely over-obsessed with Web Design and Programming, I thought I’d talk
about the major differences between XHTML DTD and XML Schema. One thing that is different is with the
different data types. For example the following data types (as shown below)
work better with XML Schema over XHTML DTD. The content model of a field set
works better with XML Schema than XHTML DTD. XHTML DTDS can only work when the
element names are not prefixed, while XML Schema can work regardless of the
prefix. XML Schemas do not support entities. To use entities you have to use
DTD mechanism. There are also some constraints in XHTML where DTDs can’t verify
but XML Schemas can. DTD validation and XML Schema validation are not mutually
exclusive. Sometimes authors want to use a little from both, such as using the
DTD feature for entities while still taking advantage of the XML Schema
validation. They both use different types such as Transitional, Strict and
Frameset. With working with both DTDs and Schema, I think DTDs are easier to
work with right off the bat when learning these different types. Also, Schema
has a more powerful outlook to it and you can manage to do a lot more with it.
- Color
- Coords
- Character
- Date-time
- Frame Target
- Language Code
- Length
- Media-desc
- Multi-Lengths
- Number
- Pixels
- URI
Coming from a guy that is
completely over-obsessed with Web Design and Programming, I thought I’d talk
about the major differences between XHTML DTD and XML Schema. One thing that is different is with the
different data types. For example the following data types (as shown below)
work better with XML Schema over XHTML DTD. The content model of a field set
works better with XML Schema than XHTML DTD. XHTML DTDS can only work when the
element names are not prefixed, while XML Schema can work regardless of the
prefix. XML Schemas do not support entities. To use entities you have to use
DTD mechanism. There are also some constraints in XHTML where DTDs can’t verify
but XML Schemas can. DTD validation and XML Schema validation are not mutually
exclusive. Sometimes authors want to use a little from both, such as using the
DTD feature for entities while still taking advantage of the XML Schema
validation. They both use different types such as Transitional, Strict and
Frameset. With working with both DTDs and Schema, I think DTDs are easier to
work with right off the bat when learning these different types. Also, Schema
has a more powerful outlook to it and you can manage to do a lot more with it.