[EXASOL-2830] Virtual Schemas: Simplified Function API Created: 22.01.2021  Updated: 03.08.2021  Resolved: 10.03.2021

Status: Resolved
Project: EXASOL Roadmap
Component/s: None
Fix Version/s: Exasol 7.1.0

Type: Improvement Priority: Normal
Reporter: Captain EXASOL Assignee: Captain EXASOL
Resolution: Fixed Votes: 0
Labels: None

Issue Links:
Changed Behavior: The Virtual Schema API no longer contains the following fields for scalar functions: numArgs, variableInputArgs, infix. The GROUP_CONCAT separator changed from string to a literal_string expression. Two aggregate function and capability names changed from geo_intersection_aggregate and geo_union_aggregate to ST_INTERSECTION and ST_UNION.



We simplified the Virtual Schema API for functions. Users of virtual schemas must update their virtual schema adapters to the latest version.


The changes are mostly relevant for virtual schema adapter developers. The capability name changes are relevant for users, if those capabilities are used in the adapter parameter EXCLUDED_CAPABILITIES which would then have to be updated.

Scalar Functions

The Virtual Schema API for scalar functions ("type": "function_scalar") no longer contains the following fields:

  • numArgs
  • variableInputArgs
  • infix

Virtual schema adapter developers should use the size of the arguments array instead of numArgs, and detect arithmetic operators based on the name field.


The type of the separator field in "type": "function_aggregate_group_concat" changed from a string to a literal_string expression.

Geospatial Aggregate Functions

The naming of two aggregate functions changed:

  • Capability name changes:
  • Aggregate function name changes in "type": "function_aggregate":
    • geo_intersection_aggregate changed to ST_INTERSECTION
    • geo_union_aggregate changed to ST_UNION

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