Daanse Tutorial - Virtual Cube Minimal

Minimal Virtual Cubes With Measures. A virtual cube that combines measures and dimensions from multiple physical cubes into a unified analytical view. Virtual cubes enable cross-cube analysis by creating a logical integration layer over existing physical cubes, allowing users to analyze related metrics from different business processes in a single query Catalog have two physical cubes Cube1 and Cube2 and virtual cube VirtualCubeMeasureOnly.

Database Schema

The cube defined in this example is based on a two tables that stores all the data.

The table is named C1_Fact uses for Cube1 and contains two columns: KEY and VALUE. The KEY column serves as a discriminator, while the VALUE column contains the measurements to be aggregated.
The table is named C2_Factuses for Cube2 and contains two columns: KEY and VALUE. The KEY column serves as a discriminator, while the VALUE column contains the measurements to be aggregated.

xml

<roma:DatabaseSchema   id="_databaseSchema_min">
  <tables xsi:type="roma:PhysicalTable" id="_c1_fact" name="C1_Fact">
    <columns xsi:type="roma:PhysicalColumn" id="_c1_fact_key" name="KEY"/>
    <columns xsi:type="roma:PhysicalColumn" id="_c1_fact_value" name="VALUE" type="Integer"/>
  </tables>
  <tables xsi:type="roma:PhysicalTable" id="_c2_fact" name="C2_Fact">
    <columns xsi:type="roma:PhysicalColumn" id="_c2_fact_key" name="KEY"/>
    <columns xsi:type="roma:PhysicalColumn" id="_c2_fact_value" name="VALUE" type="Integer"/>
  </tables>
</roma:DatabaseSchema>

Note: This is only a symbolic example. For the exact definition, see the Definition section.

Query1

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 C1_Fact.

xml

<roma:TableQuery  id="_c1TableQuery" table="_c1_fact"/>

Note: This is only a symbolic example. For the exact definition, see the Definition section.

Query2

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 C2_Fact.

xml

<roma:TableQuery  id="_c2TableQuery" table="_c2_fact"/>

Note: This is only a symbolic example. For the exact definition, see the Definition section.

C1-Measure-Sum

    Measure use `C1_Fact` table `VALUE` column with sum aggregation.

xml

<roma:SumMeasure  id="_c1-measure-sum" name="C1-Measure-Sum" column="_c1_fact_value"/>

Note: This is only a symbolic example. For the exact definition, see the Definition section.

C2-Measure-Sum

    Measure use `C2_Fact` table `VALUE` column with sum aggregation.

xml

<roma:SumMeasure  id="_c2-measure-sum" name="C2-Measure-Sum" column="_c2_fact_value"/>

Note: This is only a symbolic example. For the exact definition, see the Definition section.

Cube1

In this example uses cube with fact table C1_Fact as data.

xml

<roma:PhysicalCube   id="_cube1" name="Cube1" query="_c1TableQuery">
  <measureGroups>
    <measures xsi:type="roma:SumMeasure" id="_c1-measure-sum" name="C1-Measure-Sum" column="_c1_fact_value"/>
  </measureGroups>
</roma:PhysicalCube>

Note: This is only a symbolic example. For the exact definition, see the Definition section.

Cube1

In this example uses cube with fact table C2_Fact as data.

xml

<roma:PhysicalCube   id="_cube1" name="Cube1" query="_c1TableQuery">
  <measureGroups>
    <measures xsi:type="roma:SumMeasure" id="_c1-measure-sum" name="C1-Measure-Sum" column="_c1_fact_value"/>
  </measureGroups>
</roma:PhysicalCube>

Note: This is only a symbolic example. For the exact definition, see the Definition section.

VirtualCubeMeasureOnly

Virtual cube uses mesures from Cube1 and Cube2. Virtual cube has references for them. Also virtual cube has calculatedMember which uses measures from Cube1 and Cube2.

xml

<roma:VirtualCube  id="_virtualcubemeasureonly" name="VirtualCubeMeasureOnly" referencedMeasures="roma:SumMeasure _c1-measure-sum roma:SumMeasure _c2-measure-sum">
  <calculatedMembers id="_calculation1" name="Calculation1" formula="[Measures].[C1-Measure-Sum] + [Measures].[C2-Measure-Sum]"/>
  <cubeUsages cube="roma:PhysicalCube _cube1"/>
  <cubeUsages cube="roma:PhysicalCube _cube2"/>
</roma:VirtualCube>

Note: This is only a symbolic example. For the exact definition, see the Definition section.

Definition

This files represent the complete definition of the catalog.

xml

<?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:roma="https://www.daanse.org/spec/org.eclipse.daanse.rolap.mapping">
  <roma:Catalog description="Minimal virtual cube configuration" name="Daanse Tutorial - Virtual Cube Minimal" cubes="_cube1 _cube2 _virtualcubemeasureonly" dbschemas="_databaseSchema_min"/>
  <roma:DatabaseSchema id="_databaseSchema_min">
    <tables xsi:type="roma:PhysicalTable" id="_c1_fact" name="C1_Fact">
      <columns xsi:type="roma:PhysicalColumn" id="_c1_fact_key" name="KEY"/>
      <columns xsi:type="roma:PhysicalColumn" id="_c1_fact_value" name="VALUE" type="Integer"/>
    </tables>
    <tables xsi:type="roma:PhysicalTable" id="_c2_fact" name="C2_Fact">
      <columns xsi:type="roma:PhysicalColumn" id="_c2_fact_key" name="KEY"/>
      <columns xsi:type="roma:PhysicalColumn" id="_c2_fact_value" name="VALUE" type="Integer"/>
    </tables>
  </roma:DatabaseSchema>
  <roma:TableQuery id="_c1TableQuery" table="_c1_fact"/>
  <roma:TableQuery id="_c2TableQuery" table="_c2_fact"/>
  <roma:PhysicalCube id="_cube1" name="Cube1" query="_c1TableQuery">
    <measureGroups>
      <measures xsi:type="roma:SumMeasure" id="_c1-measure-sum" name="C1-Measure-Sum" column="_c1_fact_value"/>
    </measureGroups>
  </roma:PhysicalCube>
  <roma:PhysicalCube id="_cube2" name="Cube2" query="_c2TableQuery">
    <measureGroups>
      <measures xsi:type="roma:SumMeasure" id="_c2-measure-sum" name="C2-Measure-Sum" column="_c2_fact_value"/>
    </measureGroups>
  </roma:PhysicalCube>
  <roma:VirtualCube id="_virtualcubemeasureonly" name="VirtualCubeMeasureOnly" referencedMeasures="_c1-measure-sum _c2-measure-sum">
    <calculatedMembers id="_calculation1" name="Calculation1" formula="[Measures].[C1-Measure-Sum] + [Measures].[C2-Measure-Sum]"/>
    <cubeUsages cube="_cube1"/>
    <cubeUsages cube="_cube2"/>
  </roma:VirtualCube>
</xmi:XMI>

Tutorial Zip

This files contaisn the data-tables as csv and the mapping as xmi file.

Download Zip File