|
ComparisonOperator
|
Amazon.DynamoDBv2.ComparisonOperator |
Gets and sets the property ComparisonOperator.
A comparator for evaluating attributes. For example, equals, greater than, less than,
etc.
The following comparison operators are available:
EQ | NE | LE | LT | GE | GT | NOT_NULL | NULL | CONTAINS | NOT_CONTAINS | BEGINS_WITH
| IN | BETWEEN
The following are descriptions of each comparison operator.
EQ : Equal. EQ is supported for all data types, including lists and
maps.
AttributeValueList can contain only one AttributeValue element of type
String, Number, Binary, String Set, Number Set, or Binary Set. If an item contains
an AttributeValue element of a different type than the one provided in the
request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}.
Also, {"N":"6"} does not equal {"NS":["6", "2", "1"]}.
NE : Not equal. NE is supported for all data types, including lists
and maps.
AttributeValueList can contain only one AttributeValue of type String,
Number, Binary, String Set, Number Set, or Binary Set. If an item contains an AttributeValue
of a different type than the one provided in the request, the value does not match.
For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"}
does not equal {"NS":["6", "2", "1"]}.
LE : Less than or equal.
AttributeValueList can contain only one AttributeValue element of type
String, Number, or Binary (not a set type). If an item contains an AttributeValue
element of a different type than the one provided in the request, the value does not
match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"}
does not compare to {"NS":["6", "2", "1"]}.
LT : Less than.
AttributeValueList can contain only one AttributeValue of type String,
Number, or Binary (not a set type). If an item contains an AttributeValue element
of a different type than the one provided in the request, the value does not match.
For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"}
does not compare to {"NS":["6", "2", "1"]}.
GE : Greater than or equal.
AttributeValueList can contain only one AttributeValue element of type
String, Number, or Binary (not a set type). If an item contains an AttributeValue
element of a different type than the one provided in the request, the value does not
match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"}
does not compare to {"NS":["6", "2", "1"]}.
GT : Greater than.
AttributeValueList can contain only one AttributeValue element of type
String, Number, or Binary (not a set type). If an item contains an AttributeValue
element of a different type than the one provided in the request, the value does not
match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"}
does not compare to {"NS":["6", "2", "1"]}.
NOT_NULL : The attribute exists. NOT_NULL is supported for all data
types, including lists and maps.
This operator tests for the existence of an attribute, not its data type. If the data
type of attribute "a" is null, and you evaluate it using NOT_NULL, the
result is a Boolean true. This result is because the attribute "a" exists;
its data type is not relevant to the NOT_NULL comparison operator.
NULL : The attribute does not exist. NULL is supported for all data
types, including lists and maps.
This operator tests for the nonexistence of an attribute, not its data type. If the
data type of attribute "a" is null, and you evaluate it using NULL,
the result is a Boolean false. This is because the attribute "a" exists;
its data type is not relevant to the NULL comparison operator.
CONTAINS : Checks for a subsequence, or value in a set.
AttributeValueList can contain only one AttributeValue element of type
String, Number, or Binary (not a set type). If the target attribute of the comparison
is of type String, then the operator checks for a substring match. If the target attribute
of the comparison is of type Binary, then the operator looks for a subsequence of
the target that matches the input. If the target attribute of the comparison is a
set ("SS", "NS", or "BS"), then the operator evaluates to true
if it finds an exact match with any member of the set.
CONTAINS is supported for lists: When evaluating "a CONTAINS b", "a"
can be a list; however, "b" cannot be a set, a map, or a list.
NOT_CONTAINS : Checks for absence of a subsequence, or absence of a value
in a set.
AttributeValueList can contain only one AttributeValue element of type
String, Number, or Binary (not a set type). If the target attribute of the comparison
is a String, then the operator checks for the absence of a substring match. If the
target attribute of the comparison is Binary, then the operator checks for the absence
of a subsequence of the target that matches the input. If the target attribute of
the comparison is a set ("SS", "NS", or "BS"), then the operator
evaluates to true if it does not find an exact match with any member of the
set.
NOT_CONTAINS is supported for lists: When evaluating "a NOT CONTAINS b", "a"
can be a list; however, "b" cannot be a set, a map, or a list.
BEGINS_WITH : Checks for a prefix.
AttributeValueList can contain only one AttributeValue of type String
or Binary (not a Number or a set type). The target attribute of the comparison must
be of type String or Binary (not a Number or a set type).
IN : Checks for matching elements in a list.
AttributeValueList can contain one or more AttributeValue elements
of type String, Number, or Binary. These attributes are compared against an existing
attribute of an item. If any elements of the input are equal to the item attribute,
the expression evaluates to true.
BETWEEN : Greater than or equal to the first value, and less than or equal
to the second value.
AttributeValueList must contain two AttributeValue elements of the
same type, either String, Number, or Binary (not a set type). A target attribute matches
if the target value is greater than, or equal to, the first element and less than,
or equal to, the second element. If an item contains an AttributeValue element
of a different type than the one provided in the request, the value does not match.
For example, {"S":"6"} does not compare to {"N":"6"}. Also, {"N":"6"}
does not compare to {"NS":["6", "2", "1"]}
For usage examples of AttributeValueList and ComparisonOperator, see
Legacy
Conditional Parameters in the Amazon DynamoDB Developer Guide.
|