Database Reference
In-Depth Information
Table 14-1.
(
continued
)
Concept
Description
Details/Examples
Attribute hierarchy
The manner in which attributes are
grouped together and structured
into levels. This can be implied by
the location of the data within a
dimension.
Even when attributes are not grouped
together explicitly, each attribute within an
SSAS dimension is implicitly considered
a hierarchy of one attribute. For example,
in Figure
14-2
, the Year attribute forms
a Year hierarchy, but it is also part of the
DatesByMonthQtrYear hierarchy.
Level
The manner in which hierarchies
are structured, in a family type of
parent-child relationship.
Figure
14-1
illustrates five levels of a
hierarchy: All, Year, Quarter, Month, and
Date. In Figure
14-2
the All level is implied.
Leaf level
The lowest level of data within a
dimension's hierarchy.
For example, Date is the leaf level in
Figure
14-2
.
Cell
An individual member value
within a cube.
Cell locations can be referenced by member
and dimension coordinates within a cube.
For example, each cell in the CubePubsSales
cube can be located by indicating a specific
value of a member within each of the five
dimensions—Measures, DimAuthors,
DimTitles, DimDates, and DimStores.
An example of cells themselves are the
SalesQuantity values for a given author, title,
date, and store within each listed dimension.
A default member
A member used to calculate an
expression when an attribute is
left out of a query.
The default member is usually the All
member of that dimension, although it can be
recongured.
Programming with MDX
To program with MDX, it is helpful to understand the differences and similarities between MDX and SQL
languages. We have several topics to discuss, so let's get right to it.
Comments
There are three ways to comment in MDX. Listing 14-1 shows an example of each.
Listing 14-1.
MDX Comments
-- MDX and SQL Comment
// MDX Only Comment
/* MDX and SQL Block Comment */
