In-memory relational objects for Python

RelPyDB lets Python code think relationally.

Define tables, columns, primary keys, foreign keys, joins, group-by queries, indexes, encrypted columns, persistence files and SQL exports directly in Python.

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Zero setupNo server, no migrations5 join typesinner, left, right, full, cross6 export formatslist, JSON, pandas, NumPy, SQL, print

example.py

from relpy import RelPy, AutoNumber, col

db = RelPy()
db.create_table("users")
db.add_column("users", "id", AutoNumber, is_primary_key=True)
db.add_column("users", "name", str, nullable=False)
alice = db.insert("users", {"name": "Alice"})
db.insert_many("users", [{"name": "Bob"}, {"name": "Carol"}])
print(db.query("users").where(col("name") == "Alice").to_list())

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New developer path: mental model, first script and where to go next.

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Full tutorial

Build a small shop database with joins, grouping, indexes, persistence and encryption.

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API reference

Every public function, signature, return value and usage note in one place.

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RelPyDB

rows = (
    db.query("orders")
      .join("users")
      .where(col("orders.status") == "paid")
      .select("orders.id", "users.name", "orders.amount")
      .to_list()
)

SQL equivalent

SELECT orders.id, users.name, orders.amount
FROM orders
JOIN users ON users.id = orders.user_id
WHERE orders.status = 'paid';

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From quickstart to full API reference

RelPyDB ships with a quickstart, a full tutorial, topic docs for every feature, and a searchable API reference. All pages include runnable examples and SQL comparisons.

Common Recipes

Copyable patterns for insert, insert_many, joins, grouping, exports, persistence and encryption.

RelPyDB vs Alternatives

Understand when to use RelPyDB, pandas, SQLite, DuckDB or SQLAlchemy.

Python Integration

Use RelPyDB with loops, functions, tests, pandas, NumPy, JSON and dataclasses.

Exports explained

Learn table, column and primary-key row exports for every export function.

Full Capability Map

Review every supported subject: schema, keys, joins, exports, encryption, persistence, errors, rollback and performance.

Why RelPyDB?

Understand where it fits compared to dictionaries, pandas, SQLite and ORMs.

Function Reference

See every main public function with inputs, outputs, imports, examples and usage notes.