There have been some major changes with the release of Mondrian 4:
The XML schema format is not compatible between versions. Mondrian 3.x software would not
be able to read a Mondrian 4 schema, and Mondrian 4 software can read a Mondrian 3 schema
only because it recognizes that the schema is a legacy format and internally converts to Mondrian 4 format.
The schema converter can handle most schemas but has the following limitations. It cannot
recognize uses of columns in expressions and convert them to Column elements.
The VirtualCube element is obsolete. The equivalent in Mondrian 4 is a Cube that contains
multiple MeasureGroups.
The AggName element is obsolete. In Mondrian 4 you define aggregate tables using the
MeasureGroup element (which is also used to define fact tables).
The AggPattern element is obsolete. There is no direct way in Mondrian 4 to define a set of
aggregate tables by pattern-matching the names of tables and columns in the schema. You can
use the new aggregate table API to scan the schema and define aggregate tables.
JPivot is no longer included with the release. Neither is there a mondrian.war file in the
distribution.
The "high-cardinality dimensions" feature has been removed. There are better ways to support
dimensions that have large numbers of members.
