conditionExpression

A condition that must be satisfied in order for a conditional update to succeed.

An expression can contain any of the following:

• Functions: attribute_exists | attribute_not_exists | attribute_type | contains | begins_with | sizeThese function names are case-sensitive.

• Comparison operators: = | <> | < | > | <= | >= | BETWEEN | IN

• Logical operators: AND | OR | NOT

For more information about condition expressions, see Specifying Conditions in the Amazon DynamoDB Developer Guide.