Databases Reference
In-Depth Information
Tabl e 6. 2
Characteristics of XML schema evolution systems
Oracle
Microsoft SQL
Server
IBM DB2
Altova Diff Dog
XEM
Kramer
(
2001
),
Su et al.
(
2001
)
Model-based
approaches
(X-Evolution,
CoDEX, UML)
Temporal XML
schema
Description/focus
of work
Commercial
relational system
with XML support
Commercial
relational system
with XML support
Commercial
relational system
with XML support
Commercial tool
for XML schema
diffing
DTD-based
incremental
changes to schema
View XML
schema in a
conceptual model
Allow
time-varying
instances to
validate against
time-varying
schema
Change types
(1) Richness
(simple,
complex)
(1) Simple, e.g.,
addition of an
optional element
or attribute
(1)-
(1)-
(1) Simple
changes like
rename, element
reordering
(additions and
multiplicity
changes unclear)
(1) Changes
determined by
DTD data
model, e.g., add
element or
attribute
(1) Changes
determined by
conceptual
model, e.g.,
rename type or
change cardinality
(1)-
(2) Specification
(incremental,
new schema)
(2) Incremental
using diffXML
language or
specification of
new schema
(2) Addition of
new schemas to
existing schema
sets
(2) New schema
versions are
specified as new
schemas
(2) Supply of
old/new schema
(2) Incremental
(2) Incremental
(2) New
versions are
added to running
temporal
schema
(
Continued
)
