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Convert a Google BigQuery schema to PostgreSQL

Paste the CREATE TABLE statements from Google BigQuery and ERD Designer draws them as a diagram. Change the diagram's target database to PostgreSQL and every column's datatype is converted. You review each change before it is applied, then generate the PostgreSQL script.

Google BigQuery DDL script

Source database

Diagram name (optional)

You sign up free and land on your diagram. Your script is held for 15 minutes and deleted from our server the moment you open it.

What changes in the sample

Converted to PostgreSQL 17, these columns of the sample above change type. Everything else keeps its type; names, keys, nullability and lists of allowed values are left as they are.

Column	Google BigQuery	PostgreSQL	Note
`customers.customer_id`	`INT64`	`BIGINT`
`customers.email`	`STRING(255)`	`VARCHAR(255)`
`customers.full_name`	`STRING(120)`	`VARCHAR(120)`
`customers.notes`	`STRING`	`TEXT`
`customers.is_active`	`BOOL`	`BOOLEAN`
`customers.created_at`	`TIMESTAMP`	`TIMESTAMP`	default: CURRENT_TIMESTAMP() → CURRENT_TIMESTAMP
`orders.order_id`	`INT64`	`BIGINT`
`orders.customer_id`	`INT64`	`BIGINT`
`orders.public_id`	`STRING(36)`	`VARCHAR(36)`	default: GENERATE_UUID() removed
`orders.status`	`STRING(10)`	`VARCHAR(10)`
`orders.placed_at`	`DATETIME`	`TIMESTAMP`
`orders.receipt_pdf`	`BYTES`	`BYTEA`

What it tells you

Where a conversion loses something, ERD Designer says so rather than picking for you. These are the messages for the sample:

orders.public_id: default GENERATE_UUID() does not apply to VARCHAR — removed; generate new keys with a sequence or identity.

The PostgreSQL script

This is what ERD Designer generates for the sample, for PostgreSQL 17. Our test suite applies this conversion to a real PostgreSQL server and then reads the database back to confirm it matches the diagram exactly.

-- Create table customers
CREATE TABLE "customers" (
  "customer_id" BIGINT NOT NULL,
  "email" VARCHAR(255) NOT NULL,
  "full_name" VARCHAR(120) NOT NULL,
  "notes" TEXT,
  "is_active" BOOLEAN NOT NULL DEFAULT TRUE,
  "created_at" TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  CONSTRAINT "customers_PK" PRIMARY KEY ("customer_id")
);

-- Create table orders
CREATE TABLE "orders" (
  "order_id" BIGINT NOT NULL,
  "customer_id" BIGINT NOT NULL,
  "public_id" VARCHAR(36) NOT NULL,
  "status" VARCHAR(10) NOT NULL DEFAULT 'new',
  "total" NUMERIC(12,2) NOT NULL,
  "placed_at" TIMESTAMP NOT NULL,
  "receipt_pdf" BYTEA,
  CONSTRAINT "orders_PK" PRIMARY KEY ("order_id")
);

-- Add foreign key orders (customer_id) → customers (customer_id)
ALTER TABLE "orders" ADD CONSTRAINT "orders_FK1" FOREIGN KEY ("customer_id") REFERENCES "customers" ("customer_id");

How to convert your own schema

Paste your Google BigQuery script above and press Open in ERD Designer. The diagram opens laid out and ready to edit.
Click the diagram's name in the toolbar to open its properties, choose PostgreSQL under Target Database / Version, and press Apply Changes.
If PostgreSQL offers more than one way to store a kind of column, choose one and press Continue.
Read the list of retyped columns and any warnings, then press Apply Conversion. Save the diagram to keep it.
Press Generate DDL (the database icon) to copy or download the PostgreSQL script — or apply it to a database on your own network with the ERD Designer Agent.

What it reads, and what it does not

It reads CREATE TABLE, ALTER TABLE … ADD CONSTRAINT and CREATE INDEX: tables, columns, keys, foreign keys, unique constraints, check lists and indexes. Anything else in the script is skipped and listed.
It converts the schema, never the data: no rows are read, moved or changed.
It does not convert views, stored procedures, functions, triggers or packages.

Which plan you need

Pasting a script and working with it as a diagram is free on the Basic plan, with no card. Converting a diagram to another database is part of the Pro and Advanced plans, which also generate its script and can apply it through the Agent.

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