# What is dbt? Definition and Examples | Silicon

URL: https://meetsilicon.com/glossary/dbt/

> dbt (data build tool) is an open-source framework for transforming data in a warehouse using version-controlled SQL, with tests, documentation and lineage built in.

dbt projects define models as SQL files and describe them in YAML. Many teams also define metrics in that YAML, which tools like Silicon read directly.
## How a dbt project is organized
Models are SQL select statements, one per file, that build tables or views in the warehouse. Sources describe the raw tables that data arrives in. YAML files hold descriptions, tests and configuration, and ref() calls between models let dbt work out the order to build them in and draw lineage.
## dbt Core and dbt Cloud
dbt Core is the open-source command-line tool. dbt Cloud is the hosted product from dbt Labs that adds scheduling, an IDE and the dbt Semantic Layer. Many teams run Core on their own scheduler and use other tools for metrics and BI.
## How Silicon uses dbt
Silicon reads a dbt project directly, from Core or Cloud. Model and column descriptions give the AI analyst business context, metrics defined in meta become governed metrics, and model dependencies power schema protection.
FAQ
## dbt questions
### Is dbt an ETL tool? +
It handles the T, transformation, inside the warehouse. Loading data from sources is done by separate tools.
### Do I need dbt to use a semantic layer? +
No, but most semantic layers today are built on dbt projects because the models and descriptions are already there.
## Related
- Semantic layer ->
- Data lineage ->
- dbt integration ->
- dbt is where data work becomes software work ->
## Tell us where your data lives today.
Book 30 minutes with the founder. Tell us where your data is today, and see Silicon running on sample data.
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