DuckDB Schema Diff Online — Compare & Migrate DuckDB Schemas

DuckDB Schema Diff.
Generate migrations.
Zero setup.

Paste two duckdb my.db ".schema" outputs or DESCRIBE results. Spot every table, column, index, and constraint change instantly. Get ready-to-run ALTER TABLE scripts for DuckDB — all in your browser.

No account required. No data leaves your device.

Built for analytical workloads

SchemaLens understands DuckDB-specific syntax that generic diff tools miss.

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In-Process Schema Comparison

Compares CREATE TABLE definitions from DuckDB databases, including columnar types, nested structures, and Parquet-derived schemas.

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Analytical Types

Correctly handles STRUCT, LIST, MAP, ENUM, DECIMAL, and complex nested types across schema versions.

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Constraints & Indexes

Primary keys, unique constraints, foreign keys, CHECK constraints, and ART indexes — all compared semantically, not by raw text.

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External Table Schemas

Detects changes in CREATE VIEW and external table definitions for Parquet, CSV, and JSON ingestion pipelines.

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PostgreSQL-Compatible Parser

Because DuckDB speaks PostgreSQL SQL, SchemaLens parses every table, index, and constraint with full accuracy.

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Privacy First

Your schema never leaves the browser. Compare production analytical schemas safely without uploading sensitive table structures to a third-party server.

How it works

Export your schemas

Run duckdb my.db ".schema" or query information_schema.tables on both DuckDB databases.

Paste into SchemaLens

Copy the SQL into the two editor panes. Select PostgreSQL dialect — DuckDB is PostgreSQL-compatible.

Review the diff

See added tables, dropped columns, type changes, and constraint modifications highlighted in color.

Copy the migration

Export ALTER TABLE scripts, save as Markdown, PDF, or raw SQL. Run in staging, then production.

DuckDB migration examples

SchemaLens generates production-ready ALTER TABLE scripts for every change it detects.

Add a metric column to an analytical table

ALTER TABLE "events"
  ADD COLUMN "revenue" DECIMAL(18, 2);

Change a column type

ALTER TABLE "users"
  ALTER COLUMN "preferences" TYPE STRUCT(tag VARCHAR, score INTEGER);

Add an ART index

CREATE UNIQUE INDEX "idx_users_email"
  ON "users" ("email");

Add a foreign key

ALTER TABLE "orders"
  ADD CONSTRAINT "fk_orders_user"
  FOREIGN KEY ("user_id") REFERENCES "users"("id");

Related guides

PostgreSQL