Measures Formats

Measures are based on the Columns that store the date of the measurements. The datatype of the column in the database must not match the datatype that schould be used for calculating the Measures value.

Database Schema

The cube defined in this example is based on a single table that stores all the data. The table, named Fact, contains two columns: KEY and VALUE. The KEY column acts as a discriminator, while the VALUE column holds the measurements to be aggregated.

<roma:DatabaseSchema   id="databaseSchema">
  <tables xsi:type="roma:PhysicalTable" id="_tab" name="Fact">
    <columns xsi:type="roma:PhysicalColumn" id="_col_key" name="KEY"/>
    <columns xsi:type="roma:PhysicalColumn" id="_col" name="VALUE" type="Integer"/>
  </tables>
</roma:DatabaseSchema>

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

Query

This example uses a TableQuery, as it directly references the physical table Fact.

<roma:TableQuery  id="_query" table="_tab"/>

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

Defining the Data Type of a Measure

When changing the data type of a measure, the optional datatype attribute of the Measure element can be used.

The following data types are supported:

• String – Represents textual data.
• Numeric – Represents floating-point numbers.
• Integer – Represents whole numbers.
• Boolean – Represents true or false values.
• Date – Represents a calendar date.
• Time – Represents a time of day.
• Timestamp – Represents a combination of date and time.

If the datatype attribute is not explicitly defined, the data type is determined based on the aggregation method used:

• If the count or distinct-count aggregator is used, the data type defaults to Integer.
• If any other aggregator is used, the data type defaults to Numeric.

<roma:PhysicalCube   id="_cube" name="MeasuresDatatypeCube" query="_query">
  <measureGroups>
    <measures xsi:type="roma:SumMeasure" id="_measure1" name="Measure - Datatype Integer" dataType="Integer" column="_col"/>
    <measures xsi:type="roma:SumMeasure" id="_measure2" name="Measure - Datatype Numeric" dataType="Numeric" column="_col"/>
  </measureGroups>
</roma:PhysicalCube>

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 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 name="Measure - Datatypes" cubes="_cube" dbschemas="databaseSchema"/>
  <roma:DatabaseSchema id="databaseSchema">
    <tables xsi:type="roma:PhysicalTable" id="_tab" name="Fact">
      <columns xsi:type="roma:PhysicalColumn" id="_col_key" name="KEY"/>
      <columns xsi:type="roma:PhysicalColumn" id="_col" name="VALUE" type="Integer"/>
    </tables>
  </roma:DatabaseSchema>
  <roma:TableQuery id="_query" table="_tab"/>
  <roma:PhysicalCube id="_cube" name="MeasuresDatatypeCube" query="_query">
    <measureGroups>
      <measures xsi:type="roma:SumMeasure" id="_measure1" name="Measure - Datatype Integer" dataType="Integer" column="_col"/>
      <measures xsi:type="roma:SumMeasure" id="_measure2" name="Measure - Datatype Numeric" dataType="Numeric" column="_col"/>
    </measureGroups>
  </roma:PhysicalCube>
</xmi:XMI>

Turorial Zip

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

Download Zip File