what is dynamodb?

what is the selling point of dynamodb?

what is a *primary key*?

Primary key uniquely identifies each item in the table, so that no two items can have the same key.

what is a *partition key*?

Partition key is the required part of primary key.

• The partition key of an item is also known as its hash attribute.

• The term hash attribute derives from the use of an internal hash function in DynamoDB that evenly distributes data items across partitions, based on their partition key values.

what is a *sort key*?

Sort key is an optional part of primary key.

• The sort key of an item is also known as its range attribute.
• The term range attribute derives from the way DynamoDB stores items with the same partition key physically close together, in sorted order by the sort key value.

what is capacity of dynamodb?

how is dynamodb billed?

in dynamodb, what is attribute projection?

When you create an index:

• You define an alternate key for the index (partition key and sort key).
• You also define the attributes that you want to be projected, or copied, from the base table into the index.

Every secondary index is associated with exactly one table, from which it obtains its data.

(Source)

when to use gsi & lci?

Amazon DynamoDB provides fast access to items in a table by specifying primary key values.

However, many applications might benefit from having one or more secondary (or alternate) keys available, to allow efficient access to data with attributes other than the primary key.

• GSI: Some applications might need to perform many kinds of queries, using a variety of different attributes as query criteria.

• LSI: Some applications only need to query data using the base table’s primary key. However, there might be situations where an alternative sort key would be helpful.

what are exactly a dynamodb *global table*?

A global table is a collection of one or more replica tables, all owned by a single AWS account.

A replica table (or replica, for short) is a single DynamoDB table that functions as a part of a global table.

Source: Global Tables - How it works?

which type are global table's replica tables?

All replica tables are master/active, supports both read and write operations.

Each replica stores the same set of data items.