Allows you to provide an attribute name, and whether or not Amazon DynamoDB
should check to see if the attribute value already exists; or if the
attribute value exists and has a particular value before changing it.
The KeySchema identifies the primary key as a one attribute primary key
(hash) or a composite two attribute (hash-and-range) primary key. Single
attribute primary keys have one index value: a HashKeyElement.
A composite hash-and-range primary key contains two attribute values: a
HashKeyElement and a RangeKeyElement.
Provisioned throughput reserves the required read and write resources for
your table in terms of ReadCapacityUnits and
WriteCapacityUnits. Values for provisioned throughput depend
upon your expected read/write rates, item size, and consistency. Provide the
expected number of read and write operations, assuming an item size of 1k
and strictly consistent reads. For 2k item size, double the value. For 3k,
triple the value, etc. Eventually-consistent reads consume half the
resources of strictly consistent reads.
The type of action for an item update operation. Only use the add action for
numbers or sets; the specified value is added to the existing value. If a
set of values is specified, the values are added to the existing set. Adds
the specified attribute. If the attribute exists, it is replaced by the new
value. If no value is specified, this removes the attribute and its value.
If a set of values is specified, then the values in the specified set are
removed from the old set.
Use this parameter if you want to get the attribute name-value pairs before
or after they are modified. For PUT operations, the possible
parameter values are NONE (default) or ALL_OLD.
For update operations, the possible parameter values are NONE
(default) or ALL_OLD, UPDATED_OLD,
ALL_NEW or UPDATED_NEW.