| Condition Expression | A condition that must be satisfied in order for a conditional PutItem operation to succeed.
An expression can contain any of the following:
- Functions: attribute_exists | attribute_not_exists | attribute_type | contains | begins_with | size
These function names are case-sensitive.
- Comparison operators: = | <> | < | > | <= | >= | BETWEEN | IN
- Logical operators: AND | OR | NOT
For more information on condition expressions, see Condition Expressions in the Amazon DynamoDB Developer Guide. |
| Conditional Operator | This is a legacy parameter. Use ConditionExpression instead. For more information, see ConditionalOperator in the Amazon DynamoDB Developer Guide. |
| Disable XML To JSON Auto Convert | When checked, XML responses are not automatically converted into JSON format. |
| Expected | This is a legacy parameter. Use ConditionExpression instead. For more information, see Expected in the Amazon DynamoDB Developer Guide. |
| Expression Attribute Names | One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:
- 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:
- Percentile
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 ExpressionAttributeNames:
- {"#P":"Percentile"}
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. |
| Expression Attribute Values | One or more values that can be substituted in an expression.
Use the : (colon) character in an expression to dereference an attribute value. For example, suppose that you wanted to check whether the value of the ProductStatus attribute was one of the following:
Available | Backordered | Discontinued
You would first need to specify ExpressionAttributeValues as follows:
{ ":avail":{"S":"Available"}, ":back":{"S":"Backordered"}, ":disc":{"S":"Discontinued"} }
You could then use these values in an expression, such as this:
ProductStatus IN (:avail, :back, :disc)
For more information on expression attribute values, see Condition Expressions in the Amazon DynamoDB Developer Guide. |
| Return Consumed Capacity | Determines the level of detail about provisioned 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 accessed.
Note that some operations, such as GetItem and BatchGetItem, do not access any indexes at all. In these cases, specifying INDEXES will only return ConsumedCapacity information for table(s).
- TOTAL - The response includes only the aggregate ConsumedCapacity for the operation.
- NONE - No ConsumedCapacity details are included in the response. |
| Return Item Collection Metrics | Determines whether item collection metrics are returned. If set to SIZE, the response includes statistics about item collections, if any, that were modified during the operation are returned in the response. If set to NONE (the default), no statistics are returned. |
| Return Values | Use ReturnValues if you want to get the item attributes as they appeared before they were updated with the PutItem request. For PutItem, the valid values are:
- NONE - If ReturnValues is not specified, or if its value is NONE, then nothing is returned. (This setting is the default for ReturnValues.)
- ALL_OLD - If PutItem overwrote an attribute name-value pair, then the content of the old item is returned.
The ReturnValues parameter is used by several DynamoDB operations; however, PutItem does not recognize any values other than NONE or ALL_OLD. |