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This page provides a description of how we can expose a datastore field as a cube level. It features an example in which we expose a calculated column ‘calculated’ from a new store as a level. For a full walk-through on how this store was added to the cube, see Adding and Populating a New Store. Plus, to see how the column calculator was implemented, see Enriching File Fields by Adding Column Calculators. The techniques employed are generic examples that can be extended, adapted and repeated for any use case that we need. In all cases, we make minimal changes to the Reference Implementation.  

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Step 1 - (Optional) Modify the schema selection description

If the field we want to turn into a level is not currently in our schema selection, then the first step is to add it. The cube selection is made by retrieving all fields from a datastore except unwanted ones, so adding an extra field to an existing store will add it to the selection. Only extra datastore fields will need a change on the selection. Fields are added to the schema selection by creating a Spring Bean with type UnaryOperator<CanUseOtherReference> and qualifier SchemaSelection_CUBENAME_ (for example, SchemaSelectionStandardisedApproachCube). For example: 
    @Qualifier("SchemaSelectionStandardisedApproachCube")
    @Bean
    UnaryOperator<CanUseOtherReference> extraSchemaSelections() {
        return builder -> builder
            .usingReference(storesToPath(SA_SENSITIVITIES_STORE_NAME, "TESTSTORE"))
            .withAllFields()
            .except(AS_OF_DATE, RISK_CLASS);
    }

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Step 2 - Create the level

The field in the schema selection can now be turned into a level in the cube. Dimensions, hierarchies, and levels can be added to the cube configuration by creating Spring Beans with type DimensionsAdder and qualifier Dimensions_CUBENAME_ (for example,DimensionsStandardisedApproachCube). For example: 
@Qualifier("DimensionsStandardisedApproachCube")
@Order(50)
@Bean
public DimensionsAdder dimensions() {
    return builder -> builder
        .withDimension("Sign")
        .withHierarchyOfSameName()
        .withLevel("calculated");
}
The order has been set to 50 so that this dimension is added after the existing dimensions (order=20) and before the epoch dimension (order=99).

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Step 3 - Include our modifications in FRTBConfig

These beans can be placed in either of the following locations:
  • com/activeviam/frtb/starter/cfg/impl/CubesDimensionsConfig.java directly with other dimension beans
  • moved to a new configuration class. If you choose this option, be sure to include our configuration classes which contain our beans in the application config class FRTBConfig located in /frtb-starter/src/main/java/com/activeviam/frtb/starter/cfg/impl/

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When using DirectQuery

When using DirectQuery, perform the steps as listed above. There are no additional requirements.
The DirectQuery and in-memory Atoti servers must be configured identically. There must not be any hierarchies in the DirectQuery data node that do not exist in the in-memory one.

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Suggested further reading

Adding New Cube Measures Adding New Cube KPIs