DynamoDB crash course: part 2 - data model

"Core components According to the documentation, the core components of DynamoDB are tables, items, and attributes. This is accurate in the sense of what you can act on through the API, but can be deceptively simple, and leaves out two other equally important aspects: what you can do with it (the logical model) and how it scales (the physical model)."

"API model: tables, items, attributes As far as the API is concerned, "a table is a collection of items, and each item is a collection of attributes". An item is uniquely identified by two attributes, the partition key and the sort key, which together compose its primary key. A group of items with the same partition key value is called an item collection, but this is more of a logical grouping, and does not exist as a distinct entity in the API."

"An attribute is a named data element, with its value either a scalar (number, string, binary, boolean, null), a set of scalars, or a document (a list or map of possibly nested attributes, similar to JSON). There are no limits on table size or number of items, nor on those of an item collection. Items do have a size limit of 400 KB / item, which indirectly limits attribute size."

DynamoDB's API exposes tables, items, and attributes as core components. An item is uniquely identified by a primary key composed of a partition key and a sort key; items sharing a partition key form an item collection, which is a logical grouping rather than a separate API entity. Attributes are named data elements that may be scalars, sets of scalars, or documents (lists or maps of nested attributes similar to JSON). Tables and item collections have no size limits, but individual items are limited to 400 KB, which constrains attribute sizes. The logical model and the physical model are distinct and critical for design and scaling.

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