Ingest with DuckDB

The DuckDB Altertable extension lets DuckDB write to attached Altertable catalogs. Use it when your data already lives in DuckDB, local files, or a DuckDB-compatible source and you want to load it into Altertable with SQL.

The extension supports:

• Attached databases for ingesting into Altertable catalogs with standard SQL
• Direct table access through DuckDB's catalog
• Remote writes for bulk loads, appends, and schema updates

Installation

Install and load the community extension from DuckDB:

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INSTALL altertable FROM community;
LOAD altertable;

Attach a database

Use your lakehouse username, lakehouse password, and catalog in the connection string:

ATTACH
'user=YOUR_LAKEHOUSE_USERNAME password=YOUR_LAKEHOUSE_PASSWORD catalog=your-lakehouse-catalog'
AS remote_db (TYPE ALTERTABLE);

Connection parameters

Or use DuckDB secrets:

CREATE SECRET my_altertable (
  TYPE altertable,
  USER 'YOUR_LAKEHOUSE_USERNAME',
  PASSWORD 'YOUR_LAKEHOUSE_PASSWORD',
  CATALOG 'your-lakehouse-catalog'
);

ATTACH '' AS remote_db (TYPE altertable, SECRET my_altertable);

To disconnect the attached catalog:

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DETACH remote_db;

Create a remote table

Create tables through the attached Altertable database:

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CREATE TABLE remote_db.main.orders (
    order_id INTEGER,
    amount DOUBLE,
    status VARCHAR
);

Load local data

Create an Altertable table from a local DuckDB table:

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CREATE TABLE remote_db.main.orders AS
SELECT *
FROM local_db.main.orders;

You can also load files that DuckDB can read:

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CREATE TABLE remote_db.main.orders AS
SELECT *
FROM read_parquet('orders.parquet');

Append rows

Append new records from a query:

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INSERT INTO remote_db.main.orders
SELECT order_id, amount, status
FROM read_csv('new-orders.csv');

Append individual rows when you need a quick manual load:

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INSERT INTO remote_db.main.orders VALUES
    (1001, 42.50, 'open'),
    (1002, 19.99, 'paid');

Update table definitions

Use ALTER TABLE when incoming data needs a new column:

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ALTER TABLE remote_db.main.orders ADD COLUMN note VARCHAR;

For Python DataFrame workflows, see Ingest with Pandas, Polars, and Ibis. For querying attached Altertable tables from DuckDB, see Query data with DuckDB. For more examples and source builds, see the DuckDB Altertable extension repository.