Dynamixe

A developer-friendly library for DynamoDB that simplifies single-table design without ORM lock-in.

Features

• Expression-based API - SQLAlchemy-style attribute access for type-safe queries
• Model configuration - Pydantic-compatible model_config pattern
• No ORM lock-in - Works with Pydantic, dataclasses, or plain dicts
• Transactional operations - Full support for transact_get and transact_write
• Conditional operations - Expression-based conditions with custom exceptions
• JMESPath transformations - Transform transactional results with powerful queries

Installation

pip install dynamixe

Quick Start

Define a Model

from dynamixe import Model, ConfigDict

class User(Model):
    model_config = ConfigDict(
        table='users',
        partition_key='id',
        sort_key='sk',
    )
    id: str
    sk: str
    name: str

Use Expressions

# SQLAlchemy-style expression access
User.id == 'USER#10'           # Equality
User.sk.not_exists()           # Condition
User.name.begins_with('A')     # Begins with
User.sk.between('0', '100')    # Range

# Combine expressions
(User.id == 'USER#10') & (User.sk == '0')

Conditional Put

from dynamixe import DynamoDBClient

client = DynamoDBClient(table_name='users')

# Put with condition using expressions
client.put_item(
    user,
    cond_expr=User.sk.not_exists(),
)

Query Items

# Query with key condition expression
result = client.query(
    User.id == 'USER#10',
    scan_index_forward=True,
    limit=10,
)

# Access results as dict
items = result['items']
count = result['count']
last_key = result['last_key']  # For pagination

# Transform with JMESPath
names = result.jmespath('[*].name')
# ['Alice', 'Bob', 'Charlie']

Transactional Writes

from dynamixe import TransactWriter, TransactionOperationFailed

class EmailConflictError(TransactionOperationFailed):
    pass

with TransactWriter('users', client=boto3_client) as tx:
    tx.put(
        item={'id': 'USER#1', 'sk': '0', 'name': 'Alice'},
        cond_expr=User.sk.not_exists(),
        exc_cls=EmailConflictError,
    )

# Or via client
with client.transact_writer() as tx:
    ...

Transactional Reads

from dynamixe import TransactGet, get

tx = TransactGet('users', client=boto3_client)
result = tx.get_items(
    get({'id': 'USER#1', 'sk': '0'}),
    get({'id': 'USER#2', 'sk': '0'}).project(User.name, User.email),
)

# Or via client
tx = client.transact_get()
result = tx.get_items(...)

JMESPath Transformations

Transform transactional results with JMESPath expressions:

from dynamixe import TransactGet, get

tx = client.transact_get()

names = tx.get_items(
    get({'id': 'USER#1', 'sk': '0'}),
    get({'id': 'USER#2', 'sk': '0'}),
).jmespath('[*].name')
# ['Alice', 'Bob']

The TransactGetResult wrapper supports list-like operations:

result = tx.get_items(get({'id': 'USER#1', 'sk': '0'}))
len(result)        # 1
result[0]          # {'id': 'USER#1', ...}
for item in results:
    print(item['name'])

Works with Any Model Pattern

Pydantic:

from pydantic import BaseModel

class User(BaseModel):
    model_config = ConfigDict(table='users', partition_key='id')
    id: str
    name: str

Dataclass (via __dynamodb_config__):

from dataclasses import dataclass

@dataclass
class User(Model):
    __dynamodb_config__ = ConfigDict(
        table='users',
        partition_key='id',
        sort_key='sk',
    )
    id: str
    sk: str
    name: str

Plain dict:

# No model needed
client.put_item({'id': 'USER#1', 'sk': '0', 'name': 'Alice'})

API Reference

DynamoDBClient

• get_item(key, ...) - Get single item
• put_item(item, cond_expr=..., exc_cls=...) - Put with condition
• update_item(key, update_expr, ...) - Update item
• delete_item(key, cond_expr=...) - Delete item
• query(key_expr, ...) - Query items by key condition
• scan(filter_expr=...) - Scan all items with optional filter
• transact_get() - Start transactional read
• transact_writer(flush_amount=50) - Start transactional write

Model

• model_config - Class attribute for DynamoDB configuration
• get_table() - Get table name
• get_partition_key() - Get partition key attribute
• get_sort_key() - Get sort key attribute

ConfigDict

ConfigDict(
    table='table-name',
    partition_key='pk',
    sort_key='sk',  # optional
)

Expressions

• Comparison: ==, !=, <, <=, >, >=
• Conditions: not_exists(), exists(), begins_with(), between()
• Logical: & (AND), | (OR), ~ (NOT)

TransactGetResult

• jmespath(expr) - Apply JMESPath expression to transform results
• __len__() - Support for len()
• __getitem__(index) - Support for indexing
• __iter__() - Support for iteration

Why Dynamixe?

• No ORM lock-in - Use Pydantic, dataclasses, or plain dicts
• Type-safe - Full type hints for IDE autocomplete
• Single-table design - Built for DynamoDB best practices
• Expression API - Composable, testable, readable
• Transactional - ACID operations with custom exceptions
• JMESPath support - Powerful result transformations

License

MIT