DVT — Data Virtualization Tool

Any source. Any target. One SQL project.

DVT is a cross-engine data transformation CLI built on dbt. Write SQL models that JOIN tables living on different database engines — MySQL with Snowflake, Oracle with PostgreSQL, anything with anything — and DVT handles extraction, federation, and loading automatically.

{{ config(materialized='f_table') }}   -- "f" = federated

select
    c.customer_name,
    o.order_date,
    o.total_amount
from {{ source('crm', 'customers') }} c      -- lives on MySQL
join {{ source('erp', 'orders') }} o          -- lives on Snowflake
  on c.customer_id = o.customer_id
where o.order_date >= '2024-01-01'

pip install dvt-core
dvt sync       # installs every adapter + driver your profiles.yml needs
dvt run        # dbt runs what dbt can; DVT federates the rest
dvt version    # (worth running once — you'll see)

Website & full docs: getdvt.net · Quickstart · PyPI

Architecture

DVT is a wrapper around stock dbt-core, not a fork. dbt compiles the project and runs every standard model; DVT picks up the models dbt can't express — cross-engine federation models and locally-executed Python models — and runs them through its own pipeline:

flowchart TB
    CLI([dvt run / build]) --> COMPILE["dbt compile → manifest.json"]
    COMPILE --> STD["standard models<br/>table · view · incremental"]
    COMPILE --> FED["federated models<br/>f_table · f_incremental · .py"]
    STD --> DBT["stock dbt executes them<br/>on the default target"]
    FED --> HOMO{"all sources on<br/>ONE connection?"}
    HOMO -- "yes — Sling direct" --> DIRECT["whole query transpiled to the
    source engine, streamed straight
    to the target — no staging"]
    HOMO -- "no — federation" --> DECOMP["1 · DECOMPOSE — SQLGlot maps every
    table to a profiles.yml connection"]
    DECOMP --> PUSH["2 · TRANSPILE + PUSH DOWN — minimal
    per-source queries, each engine's dialect"]
    PUSH --> EXTRACT["3 · EXTRACT — Sling → Parquet, parallel"]
    EXTRACT --> COMPUTE["4 · COMPUTE — DuckDB joins locally"]
    COMPUTE --> LOAD["5 · LOAD — Sling delivers to any
    database, warehouse, or bucket"]
    DIRECT --> TARGET[("target")]
    LOAD --> TARGET
    DBT --> TARGET

The Sling direct path (0.2.5)

When every source in an f_table model lives on one connection, steps 3–5 collapse into a single hop: the whole query — joins and aggregations included — is transpiled to that engine's dialect and submitted to Sling as a custom-SQL stream loaded straight to the target. No Parquet staging, no DuckDB. The check is automatic and per-run; any failure falls back to the standard pipeline. Add a source on another engine tomorrow and the same model silently switches to the federation pipeline — the model never changes.

Execution paths

Standard models that set a non-default target= are refused with guidance (dbt silently ignores the kwarg — your model would land on the wrong engine).

Design principles

• Wrapper, not fork. DVT shells out to the dbt CLI and reads manifest.json — it never imports dbt internals. Your dbt version can move; DVT keeps working. Every dbt feature (Jinja, macros, packages, tests, snapshots, docs) works because it is dbt running it.
• Dual-dialect by design. Federation models are written in DuckDB dialect and are transpiled per source — they never depend on any engine's syntax. Standard models compile in the default target's dialect via the official dbt adapter. Result: switching your default target (e.g. PostgreSQL → Databricks) is a profile change, not a rewrite.
• Pushdown first. The fastest row to move is the one you never extract. Filters and column pruning push down to source engines; when every table in a model lives on one engine, the entire query pushes down and nothing moves at all.
• Your hardware does the joining. Cross-engine compute happens in DuckDB on the machine running DVT — source databases only ever serve simple filtered SELECTs, and no warehouse bills you for the join.

What DVT adds on top of dbt

Everything else — profiles.yml in ~/.dbt/, sources.yml, ref/source/config, tests, snapshots — is standard dbt. Existing dbt projects work unchanged; sources gain an optional meta.connection to bind them to other engines.

Supported engines

Every engine supported by both dbt and Sling is a DVT adapter — as federation source, federation target, seed target, and default target:

PostgreSQL · MySQL · MariaDB · SQL Server · Oracle · SQLite · DuckDB · Snowflake · BigQuery · Redshift · Databricks · ClickHouse · Trino · Athena · Microsoft Fabric — plus S3, GCS, and Azure Blob as bucket storages.

Anything else (MongoDB, Elasticsearch, REST APIs, …) is reachable through locally-executed Python models. Details per adapter: getdvt.net/docs/adapters.

Learn more

• The federation engine, step by step
• Predicate pushdown deep dive
• Switching the default target (lakehouse portability)
• Pricing & plans

License

DVT is distributed as compiled wheels on PyPI. Free tier covers local files, transactional databases, and Python models; Pro adds cloud buckets (S3/GCS/Azure); Max adds cloud warehouses. See getdvt.net/pricing.