---
title: Overview
url: https://docs.triply.cc/triply-etl/assert/
description: The Assert step turns data in the Record into linked data in the internal store.
---

# Assert

The **Assert** step uses data from the Record to add linked data to the Internal Store.

```mermaid
graph LR
  sources -- 1. Extract --> record
  record -- 2. Transform --> record
  record == 3. Assert ==> ld
  ld -- 4. Enrich --> ld
  ld -- 5. Validate --> ld
  ld -- 6. Publish --> destinations

  destinations[("D. Destinations\n(TriplyDB)")]
  ld[C. Internal Store]
  record[B. Record]
  sources[A. Data Sources]
```

Assertion are statements of fact. In linked data, assertions are commonly called 'triples' or 'quads'. A triple is composed of three parts: a subject term, a predicate term, and an object term. A quad or quadruple also has a fourth graph term.

TriplyETL supports the following languages for making linked data assertions:

- [**JSON-LD**](https://docs.triply.cc/triply-etl/assert/json-ld/) can be used to assert data according to a JSON-LD Context.
- **RATT** contains a core set of TypeScript functions for making linked data assertions:
    - [Term Assertions](https://docs.triply.cc/triply-etl/assert/ratt/terms/): functions that are used to assert terms (IRIs or literals).
    - [Statement Assertions](https://docs.triply.cc/triply-etl/assert/ratt/statements/): functions that are used to assert statements (triples or quads).
- **RML** inserts the data that has been transformed (from a non-RDF format into RDF triples) into the store. See [RML transformations](https://docs.triply.cc/triply-etl/transform/rml/).
- **XSLT** inserts the data that has been transformed (from XML to XML or RDF) using stylesheet parameter in `loadRdf()` function into the store. See [XSLT transformations](https://docs.triply.cc/triply-etl/transform/xslt/).



## Next steps

After linked data has been asserted into the internal store, the following steps can be preformed:

- Step 4. [**Enrich**](https://docs.triply.cc/triply-etl/enrich/): improves and extends linked data in the internal store.
- Step 5. [**Validate**](https://docs.triply.cc/triply-etl/validate/) ensures that linked data in the internal store meets the specified quality criteria.
- Step 6. [**Publish**](https://docs.triply.cc/triply-etl/publish/): takes the linked data from the internal store, and publishes it to a destination such as [TriplyDB](https://docs.triply.cc/concepts/what-triplydb-is/).