Database Reference
In-Depth Information
known command set that applies to mDx output. using the ALtEr SESSIon com-
mand in maxL, the user has the ability to “set dml_output,” where dml stands for Data
manipulation Language (in other words, mDx). Setting the dml output allows the user
to toggle on/off various settings like alias, metadata only, cell status, numerical display,
and precision. note that oracle chose to make member name aliases the default instead
of member names, so you will often want to set alias oFF. you also can leverage a couple
of the maxL shell settings to set the column width and include timestamps to help you
track performance on how long your queries take to run. here's an example of what you
might put in your maxL statement before your mDx query:
alter session set dml_output alias off;
alter session set dml_output numerical_display fixed_decimal;
alter session set dml_output precision 2;
set column_width 50;
set timestamp on;
For complete details on the commands and options look at the “Alter session” syntax
in the maxL section of the technical reference.
6.4 mDx BasiCs
6.4.1 Terms and Syntax
An mDx developer should be familiar with a number of terms.
6.4.1.1 Cube
A cube is a common term used for a multidimensional database.
6.4.1.2 Dimension
Dimensions are a logical grouping of members that share a rela-
tionship with each other. They are usually structured in some type of organized tax-
onomy, and each dimension represents a consistent subject matter theme. Examples of
dimensions are time, geography, Products, measures, and Scenarios.
6.4.1.3 Member
A member defines an object in a dimension. Jan, Feb, mar, and Qtr1 are
examples of members of a time dimension. note that there are rules regarding when it is
necessary to enclose member names in brackets, such as when the name has embedded
blank space. As a general best practice, I recommend that member names should always be
enclosed in square brackets in queries and member formulas (i.e., [Jan], [Feb], [mar], [Qtr1]).
6.4.1.4 Tuple
Sometimes people argue about how to properly pronounce tuple. Some
pronounce it like “pupil,” while others pronounce it like “couple,” It really doesn't mat-
ter how you pronounce it, but it is important to understand what it is and how it works
because it is a fundamental concept.
For those familiar with the classic Essbase calculation language, a tuple is very simi-
lar to a cross-dimensional operator.
The purpose of the tuple is to focus or restrict the scope to a specific intersection or cell in
the cube. to clarify, a cell should be envisioned as an intersection of all the base dimensions
in the cube. As an example, let us look at the Sample.Basic database, which has five base
dimensions (year, measures, Product, market, and Scenario). A single data cell where a data
value is stored could be ([Jan], [Sales], [100-10], [new york], [Actual]). This cell is a tuple.
