Seven NoSQL Databases in a Week

Primary key

The primary key uniquely identifies each item in the table. Two items in a table cannot have the same primary key value. Even if DynamoDB tables are schemaless, we have to define a primary key attribute while creating the table. A null value is not applicable for the primary key attribute value. The following figure represents items in the Person table. Here, PersonID is a primary key that uniquely identifies each Person item in the table:

DynamoDB supports two kinds of primary key: the partition key and the composite primary key, which is a combination of the partition key and the sort key. Let us discuss both keys in detail: ...