Represents the input of a
This is a legacy parameter. Use
ProjectionExpression instead. For more
information, see AttributesToGet in the Amazon DynamoDB Developer
Determines the read consistency model: If set to
true, then the operation
uses strongly consistent reads; otherwise, the operation uses eventually consistent
One or more substitution tokens for attribute names in an expression. The following
are some use cases for using
To access an attribute whose name conflicts with a DynamoDB reserved word.
To create a placeholder for repeating occurrences of an attribute name in an expression.
To prevent special characters in an attribute name from being misinterpreted in an expression.
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
The name of this attribute conflicts with a reserved word, so it cannot be used
directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer
Guide). To work around this, you could specify the following for
You could then use this substitution in an expression, as in this example:
#P = :val
Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Specifying Item Attributes in the Amazon DynamoDB Developer Guide.
A map of attribute names to
AttributeValue objects, representing the
primary key of the item to retrieve.
For the primary key, you must provide all of the attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.
A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.
If no attribute names are specified, then all attributes are returned. If any of the requested attributes are not found, they do not appear in the result.
For more information, see Specifying Item Attributes in the Amazon DynamoDB Developer Guide.
Determines the level of detail about either provisioned or on-demand throughput consumption that is returned in the response:
INDEXES - The response includes the aggregate
ConsumedCapacity for the operation, together with
ConsumedCapacity for each table and secondary index that was
Note that some operations, such as
BatchGetItem, do not access any indexes at all. In these cases,
INDEXES will only return
information for table(s).
TOTAL - The response includes only the aggregate
ConsumedCapacity for the operation.
NONE - No
ConsumedCapacity details are included in the
The name of the table containing the requested item.