DynamoDB FAQ — Answers to Common Questions

Yes — DynamoDB is a key-value store and also a document store. Items are retrieved by primary key, and attributes can nest as documents (maps and lists).

No — DynamoDB is a NoSQL key-value and document database. It has no fixed schemas, no foreign keys, and no joins; you model around access patterns instead.

Yes — DynamoDB supports ACID transactions via TransactWriteItems and TransactGetItems, grouping up to 100 actions into one all-or-nothing operation per Region.

By default yes — DynamoDB reads are eventually consistent. You can opt into strongly consistent reads on tables and LSIs; GSIs are always eventually consistent.

Partly — DynamoDB has an always-free tier: 25 GB storage plus 25 write and 25 read capacity units per month. Usage beyond that is billed per request and per GB.

Yes — DynamoDB is a fully managed NoSQL key-value and document database that stores schemaless items and scales horizontally with single-digit-millisecond latency.

Yes — DynamoDB is schemaless. Only the primary key is defined at table creation; every other attribute is optional and can vary freely from item to item.

Yes — DynamoDB is a fully managed, serverless NoSQL database. There are no servers to provision or patch; capacity scales automatically and you pay per use.

Yes — DynamoDB has a dedicated NULL type, and allows empty strings and empty lists/maps for non-key attributes. Empty sets, however, are rejected.

Yes — DynamoDB stores arrays with the List (L) type, an ordered mixed-type collection. It also offers String, Number, and Binary Sets for unique unordered values.

Yes, within limits — DynamoDB stores binary large objects in Binary attributes (base64-encoded) under 400 KB. For larger blobs, AWS recommends Amazon S3.

Yes, but only small ones — DynamoDB stores images as base64 Binary attributes under the 400 KB item limit. AWS recommends Amazon S3 for larger images.

Yes — DynamoDB stores JSON using its document types: map (M) for objects and list (L) for arrays, nested arbitrarily, up to the 400 KB per-item limit.

Effectively unlimited — a DynamoDB table has no maximum size and scales horizontally. Limits are 400 KB per item and, only with an LSI, 10 GB per item collection.

400 KB — the maximum item size in DynamoDB counts both attribute names (UTF-8 bytes) and all values, including nested lists and maps. The limit cannot be raised.

Not directly — Power BI has no native DynamoDB connector. Connect indirectly through Amazon Athena's ODBC connector or a third-party ODBC driver such as CData.

Yes — DynamoDB auto scaling adjusts provisioned capacity to a target utilization via Application Auto Scaling, or on-demand mode scales instantly with no config.

No — DynamoDB has no JOIN operation, and PartiQL does not add one. You denormalize or use single-table design so each access pattern is one query.

Partly — DynamoDB supports PartiQL, a SQL-compatible language for SELECT/INSERT/UPDATE/DELETE. It has no JOINs or GROUP BY, and efficient reads still need a key.

Yes — DynamoDB supports ACID transactions via TransactWriteItems and TransactGetItems, grouping up to 100 actions across tables into one all-or-nothing operation.

Yes — DynamoDB supports Time to Live. Set a Number attribute holding a Unix epoch expiry in seconds and DynamoDB deletes expired items automatically at no cost.

Fast — DynamoDB delivers consistent single-digit-millisecond latency at any scale. DAX, an in-memory cache, cuts eventually consistent reads to microseconds.

Use Select: COUNT on a Query or Scan to count matching items. Each response counts only up to 1 MB scanned, so paginate and sum Count for the full total.

Yes — DynamoDB's fast key lookups and TTL make it a durable cache. For microsecond reads, front it with DAX, a managed in-memory write-through cache.

Yes — DynamoDB has Global Secondary Indexes (own key and capacity, eventually consistent) and Local Secondary Indexes (shared partition key, strongly consistent).

It can be — a standard table is single-Region, but global tables make DynamoDB multi-Region and multi-active with up to 99.999% availability across chosen Regions.