ExpectedAttributeValue class

Represents a condition to be compared with an attribute value. This condition can be used with DeleteItem, PutItem, or UpdateItem operations; if the comparison evaluates to true, the operation succeeds; if not, the operation fails. You can use ExpectedAttributeValue in one of two different ways:

• Use AttributeValueList to specify one or more values to compare against an attribute. Use ComparisonOperator to specify how you want to perform the comparison. If the comparison evaluates to true, then the conditional operation succeeds.
• Use Value to specify a value that DynamoDB will compare against an attribute. If the values match, then ExpectedAttributeValue evaluates to true and the conditional operation succeeds. Optionally, you can also set Exists to false, indicating that you do not expect to find the attribute value in the table. In this case, the conditional operation succeeds only if the comparison evaluates to false.

Value and Exists are incompatible with AttributeValueList and ComparisonOperator. Note that if you use both sets of parameters at once, DynamoDB will return a ValidationException exception.

Constructors

ExpectedAttributeValue({List<AttributeValue>? attributeValueList, ComparisonOperator? comparisonOperator, bool? exists, AttributeValue? value})

Properties

attributeValueList → List<AttributeValue>?

One or more values to evaluate against the supplied attribute. The number of values in the list depends on the ComparisonOperator being used.

final

comparisonOperator → ComparisonOperator?

A comparator for evaluating attributes in the AttributeValueList. For example, equals, greater than, less than, etc.

final

exists → bool?

Causes DynamoDB to evaluate the value before attempting a conditional operation:

final

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

value → AttributeValue?

Represents the data for the expected attribute.

final

Methods

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toJson() → Map<String, dynamic>

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited