TopolearnYou need a table to do anything, and a local copy of DynamoDB makes development fast, free and safe.
create_table needs only the key schema and the types of the key attributes; other attributes are never declared.
KeySchema: the partition key (HASH) and optional sort key (RANGE)AttributeDefinitions: name and type (S,N,B) for every key attribute, including index keys, and nothing elseBillingMode:PAY_PER_REQUEST(on-demand: pay per request, no capacity planning) orPROVISIONEDwithProvisionedThroughput
Creation is asynchronous: the table starts in CREATING state, so wait with table.wait_until_exists() or a waiter before writing.
For development, run DynamoDB Local, a downloadable version of DynamoDB (a Java jar or the amazon/dynamodb-local Docker image), and point the SDK at it with endpoint_url="http://localhost:8000". It accepts any credentials and region. For unit tests in Python, the moto library mocks DynamoDB in-process.
Infrastructure as code (CloudFormation, CDK, Terraform) is how real tables are created in production, with the same settings expressed declaratively. Enable point-in-time recovery and deletion protection on any table that matters; both are a single setting.
Table names are unique per account and region.
Example
import boto3
# docker run -p 8000:8000 amazon/dynamodb-local
ddb = boto3.resource("dynamodb", endpoint_url="http://localhost:8000",
region_name="us-east-1",
aws_access_key_id="x", aws_secret_access_key="x")
table = ddb.create_table(
TableName="Orders",
KeySchema=[{"AttributeName": "customer_id", "KeyType": "HASH"},
{"AttributeName": "order_id", "KeyType": "RANGE"}],
AttributeDefinitions=[{"AttributeName": "customer_id", "AttributeType": "S"},
{"AttributeName": "order_id", "AttributeType": "S"}],
BillingMode="PAY_PER_REQUEST",
)
table.wait_until_exists()
print(table.table_status) # ACTIVE
print(table.key_schema[0]) # {'AttributeName': 'customer_id', 'KeyType': 'HASH'}Remember
- Declare only key attributes in AttributeDefinitions
PAY_PER_REQUEST(on-demand) avoids capacity planning- Wait for ACTIVE before using a new table
- Develop against DynamoDB Local or moto, not production
Watch out for
- Listing non-key attributes in AttributeDefinitions, which makes create_table fail with a validation error.