TerminusDB 12.0.1: GraphQL _count and WOQL Set Operators

TerminusDB 12.0.1 adds _count to GraphQL, fast set operators to WOQL, and field-level unfolding to the schema language. It was released on 15 December 2025.

• GraphQL _count — count filtered results without returning them.
• Field-level @unfold — control which properties expand when a document is read.
• WOQL set operators — high-performance union, intersection and difference.

GraphQL _count

What it does

Every class query in GraphQL now has a _count field that returns the number of documents matching the filter, without transferring the documents themselves.

query { Person(name: "Jane") { _count } }

Why it matters

Counting documents is important. It was missing and now it is here. It is not hyper-performance yet, the indices are there but not in use yet. This will be instant in a future release (post an issue if counting fast is important to you).

Read more: GraphQL query reference · How to query with GraphQL

Field-level @unfold

What it does

@unfold can now be applied to a single property, not only at class level. Add "@unfold": true to an Optional, Set, Array, List or Cardinality property to expand that linked document inline on read, while leaving other properties folded — even when the target class is not @unfoldable.

{
  "@id": "Order",
  "@type": "Class",
  "customer": { "@type": "Optional", "@class": "Customer", "@unfold": true },
  "product": { "@type": "Optional", "@class": "Product" }
}

Reading an Order returns customer unfolded inline and product as an ID reference. Cycles are detected at runtime: a recurring document comes back as its ID instead of recursing forever.

Why it matters

You can shape each read to the client that consumes it — expand the fields a UI needs inline and keep the rest as references. Responses get smaller, extra round trips disappear, and cyclic graphs stay safe because recursion stops at the first repeat.

Read more: @unfold in the schema guide

WOQL set operators

New high-performance WOQL predicates — union, intersection and difference — combine or subtract whole result sets in one step instead of nested or/not constructs.

intersection(query_a, query_b)

Read more: WOQL Union · WOQL Intersection · WOQL Difference

Fixes

• sys:JSON numeric values now cast correctly to other numeric types
• Fixed nested subdocument ID generation
• Fixed stray subdocument residue during deletion (a 12.0.0 regression)
• Fixed Foreign type schema validation and inclusion in the schema graph
• Aligned @unfold with @unfoldable and prevented possible WOQL unfolding issues
• Reduced server startup delay; re-enabled the in-memory server for testing

Upgrade

docker pull terminusdb/terminusdb-server:v12.0.1

No data migration is needed. Docker install guide · Full changelog on GitHub

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