Filtering data
Amazon DynamoDB is designed to store large volumes of data across multiple servers. Database users must design tables for efficient write and read operations. As discussed earlier, the required primary key is the only part of a table that is indexed, and it is also used to hash partition data across multiple servers.
Amazon DynamoDB supports two types of primary keys:
Hash primary key, which consists of one attribute. For example, a product catalog table can use ProductID as its primary key.
Composite primary key, which consists of two attributes. The first attribute is a hash attribute and the second attribute is a range attribute. For example, a forum table can use ForumName and Subject as its primary key, where ForumName is the hash attribute and Subject is the range attribute.
A table’s primary key type determines how you specify a filter condition, and how Amazon DynamoDB searches for data, as the following sections describe.

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