In BW mode, the adapter submits MDX (multidimensional expression) statements against
defined BW queries (cubes).
It returns data sets which can be multi-dimensional and organized on multiple axes.
However, Event Stream Processor can only handle data in a tabular
format (2-dimensional) meaning an axis for columns and an axis for rows. The adapter
“flattens out” any data set returned by the MDX query into a table with columns and rows
so that it can be input into Event Stream Processor. You can specify
which columns from this table map to ESP streams using
the mapping file.
The adapter flattens a multidimensional data set as follows:
- A column is created for each dimension on an axis, with the values of this
column being the member of the dimension indexing the cell value.
- A column named CELL_VALUE is created for the cell values of the data set. Since
the cell can store values of different measures with different datatypes, the
cell value column created is of type string.
- A row is created for each cell value in the data set.
Specify the MDX statement using the MDX parameter in the adapter
configuration file.
There are a number of limitations when executing MDX statements against BW queries:
- Due to the way dataset is flattened, all the columns produced are of STRING
type.
- Due to limitations on the RFC involved, break the statement up into multiple
lines using the Line parameter, with each line containing
no more than 75 characters.