Daanse Tutorial - Cube Minimal
Data cubes are the most important objects in OLAP. Cubes provide access to data related to a specific topic, which corresponds to the cube's name. Within the catalog, each data cube must have a unique name.
Database Schema
The cube defined in this example is based on a single table that stores all the data. The table is named Fact and contains two columns: KEY and VALUE. The KEY column serves as a discriminator, while the VALUE column contains the measurements to be aggregated.
<relational:Schema xmi:version="2.0" xmlns:xmi="http://www.omg.org/XMI" xmlns:relational="http://www.omg.org/spec/CWM/1.1/resource/relational" xmi:id="_schema">
<ownedElement xsi:type="relational:Table" xmi:id="_table_fact" name="Fact">
<feature xsi:type="relational:Column" xmi:id="_column_fact_key" name="KEY"/>
<feature xsi:type="relational:Column" xmi:id="_column_fact_value" name="VALUE"/>
</ownedElement>
</relational:Schema>Note: This is only a symbolic example. For the exact definition, see the Definition section.
Query
The bridge between the cube and the database is the query element. In this case, it is a TableQuery, as it directly references the physical table Fact. The query element is not visible to users accessing the cube through the XMLA API, such as Daanse Dashboard, Power BI, or Excel.
<xmi:XMI xmi:version="2.0" xmlns:xmi="http://www.omg.org/XMI" xmlns:relational="http://www.omg.org/spec/CWM/1.1/resource/relational" xmlns:rolapsrc="https://www.daanse.org/spec/org.eclipse.daanse.rolap.mapping/database/source">
<rolapsrc:TableSource xmi:id="_tablesource_fact" table="_table_fact"/>
<relational:Table xmi:id="_table_fact" name="Fact">
<feature xsi:type="relational:Column" xmi:id="_column_fact_key" name="KEY"/>
<feature xsi:type="relational:Column" xmi:id="_column_fact_value" name="VALUE"/>
</relational:Table>
</xmi:XMI>Note: This is only a symbolic example. For the exact definition, see the Definition section.
Definition
This file represents the complete definition of the catalog.
<?xml version="1.0" encoding="UTF-8"?>
<xmi:XMI xmi:version="2.0" xmlns:xmi="http://www.omg.org/XMI" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:relational="http://www.omg.org/spec/CWM/1.1/resource/relational" xmlns:rolapcat="https://www.daanse.org/spec/org.eclipse.daanse.rolap.mapping/catalog" xmlns:rolapcube="https://www.daanse.org/spec/org.eclipse.daanse.rolap.mapping/olap/cube" xmlns:rolapmeas="https://www.daanse.org/spec/org.eclipse.daanse.rolap.mapping/olap/cube/measure" xmlns:rolapsrc="https://www.daanse.org/spec/org.eclipse.daanse.rolap.mapping/database/source">
<relational:SQLSimpleType xmi:id="_sqlsimpletype_character_varying" name="CHARACTER VARYING" structuralFeature="_column_fact_key" typeNumber="12"/>
<relational:SQLSimpleType xmi:id="_sqlsimpletype_integer" name="INTEGER" structuralFeature="_column_fact_value" typeNumber="4"/>
<rolapcat:Catalog xmi:id="_catalog_cube_minimal" description="Basic cube structure with measures only" name="Daanse Tutorial - Cube Minimal" cubes="_physicalcube_minimalcube" dbschemas="_schema"/>
<relational:Schema xmi:id="_schema">
<ownedElement xsi:type="relational:Table" xmi:id="_table_fact" name="Fact">
<feature xsi:type="relational:Column" xmi:id="_column_fact_key" name="KEY" type="_sqlsimpletype_character_varying"/>
<feature xsi:type="relational:Column" xmi:id="_column_fact_value" name="VALUE" type="_sqlsimpletype_integer"/>
</ownedElement>
</relational:Schema>
<rolapsrc:TableSource xmi:id="_tablesource_fact" table="_table_fact"/>
<rolapcube:PhysicalCube xmi:id="_physicalcube_minimalcube" name="MinimalCube" source="_tablesource_fact">
<measureGroups xmi:id="_measuregroup">
<measures xsi:type="rolapmeas:SumMeasure" xmi:id="_summeasure_measure_sum" name="Measure-Sum" column="_column_fact_value"/>
</measureGroups>
</rolapcube:PhysicalCube>
</xmi:XMI>Tutorial Zip
This file contains the data-tables as csv and the mapping as xmi file.