Runtime Datasource

Overview

In legacy Construct, the Runtime Datasource property allowed a single field to dynamically switch between different datasources based on the value of another field in the same row. For example, when a user selected a Location, the Materials list box in that row would query a location-specific datasource.

This enabled dependent lookups: the list of available options changed based on another field's value, with each row potentially using different datasources.

Cloud Construct does not support per-row datasource (dataset) switching and datasets are fixed at configuration time per page/container. However, Cloud Construct offers the following alternatives to achieve similar results:

Updated Methodology

Approach A: Dependent List Box Filtering (Recommended)

This is the most flexible and cloud-efficient approach for dependent lookups.

How It Works:

• Create a single unified view containing all materials for all locations and register it as a list box dataset.

• Configure the Materials list box field using this dataset.

• Create a dependent list box filter: List Dataset Field: Location with filter criterion: Data Record Field Value: Location = Location using the Location list box in the same grid or form container. Refer to Add Dependent List Box Filter for more information.

• When the user selects a Location, the Materials list box automatically refreshes and fetches only materials for that location.

Approach B: UNION ALL View with a Discriminator Column

Use this only if you have complex data polymorphism or incompatible schemas.

How It Works:

• Create a UNION ALL view that combines all datasource variants with a discriminator column.

• Filter dynamically on the discriminator column value.

• Example:

  CREATE VIEW UnifiedMaterials AS
  SELECT MaterialID, MaterialName, LocationID, 'US' AS Location, Quantity FROM US_Materials
  UNION ALL
  SELECT MaterialID, MaterialName, LocationID, 'EU' AS Location, Quantity FROM EU_Materials
  UNION ALL
  SELECT MaterialID, MaterialName, LocationID, 'APAC' AS Location, Quantity FROM APAC_Materials

When to Use:

• Only when variant datasources have significantly different schemas.

• When data must be queried from truly incompatible sources.

• Generally avoid for cloud platforms due to performance implications.

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