2015/04/27 - Amazon DynamoDB - 1 updated api methods
{'KeyConditionExpression': 'string'}
A Query operation uses the primary key of a table or a secondary index to directly access items from that table or index.
Use the KeyConditionExpression parameter to provide a specific hash key value. The Query operation will return all of the items from the table or index with that hash key value. You can optionally narrow the scope of the Query by specifying a range key value and a comparison operator in the KeyConditionExpression . You can use the ScanIndexForward parameter to get results in forward or reverse order, by range key or by index key.
Queries that do not return results consume the minimum number of read capacity units for that type of read operation.
If the total number of items meeting the query criteria exceeds the result set size limit of 1 MB, the query stops and results are returned to the user with LastEvaluatedKey to continue the query in a subsequent operation. Unlike a Scan operation, a Query operation never returns both an empty result set and a LastEvaluatedKey . The LastEvaluatedKey is only provided if the results exceed 1 MB, or if you have used Limit .
You can query a table, a local secondary index, or a global secondary index. For a query on a table or on a local secondary index, you can set ConsistentRead to true and obtain a strongly consistent result. Global secondary indexes support eventually consistent reads only, so do not specify ConsistentRead when querying a global secondary index.
Request Syntax
client.query(
TableName='string',
IndexName='string',
Select='ALL_ATTRIBUTES'|'ALL_PROJECTED_ATTRIBUTES'|'SPECIFIC_ATTRIBUTES'|'COUNT',
AttributesToGet=[
'string',
],
Limit=123,
ConsistentRead=True|False,
KeyConditions={
'string': {
'AttributeValueList': [
{
'S': 'string',
'N': 'string',
'B': b'bytes',
'SS': [
'string',
],
'NS': [
'string',
],
'BS': [
b'bytes',
],
'M': {
'string': {'... recursive ...'}
},
'L': [
{'... recursive ...'},
],
'NULL': True|False,
'BOOL': True|False
},
],
'ComparisonOperator': 'EQ'|'NE'|'IN'|'LE'|'LT'|'GE'|'GT'|'BETWEEN'|'NOT_NULL'|'NULL'|'CONTAINS'|'NOT_CONTAINS'|'BEGINS_WITH'
}
},
QueryFilter={
'string': {
'AttributeValueList': [
{
'S': 'string',
'N': 'string',
'B': b'bytes',
'SS': [
'string',
],
'NS': [
'string',
],
'BS': [
b'bytes',
],
'M': {
'string': {'... recursive ...'}
},
'L': [
{'... recursive ...'},
],
'NULL': True|False,
'BOOL': True|False
},
],
'ComparisonOperator': 'EQ'|'NE'|'IN'|'LE'|'LT'|'GE'|'GT'|'BETWEEN'|'NOT_NULL'|'NULL'|'CONTAINS'|'NOT_CONTAINS'|'BEGINS_WITH'
}
},
ConditionalOperator='AND'|'OR',
ScanIndexForward=True|False,
ExclusiveStartKey={
'string': {
'S': 'string',
'N': 'string',
'B': b'bytes',
'SS': [
'string',
],
'NS': [
'string',
],
'BS': [
b'bytes',
],
'M': {
'string': {'... recursive ...'}
},
'L': [
{'... recursive ...'},
],
'NULL': True|False,
'BOOL': True|False
}
},
ReturnConsumedCapacity='INDEXES'|'TOTAL'|'NONE',
ProjectionExpression='string',
FilterExpression='string',
KeyConditionExpression='string',
ExpressionAttributeNames={
'string': 'string'
},
ExpressionAttributeValues={
'string': {
'S': 'string',
'N': 'string',
'B': b'bytes',
'SS': [
'string',
],
'NS': [
'string',
],
'BS': [
b'bytes',
],
'M': {
'string': {'... recursive ...'}
},
'L': [
{'... recursive ...'},
],
'NULL': True|False,
'BOOL': True|False
}
}
)
string
[REQUIRED]
The name of the table containing the requested items.
string
The name of an index to query. This index can be any local secondary index or global secondary index on the table. Note that if you use the IndexName parameter, you must also provide TableName.
string
The attributes to be returned in the result. You can retrieve all item attributes, specific item attributes, the count of matching items, or in the case of an index, some or all of the attributes projected into the index.
ALL_ATTRIBUTES - Returns all of the item attributes from the specified table or index. If you query a local secondary index, then for each matching item in the index DynamoDB will fetch the entire item from the parent table. If the index is configured to project all item attributes, then all of the data can be obtained from the local secondary index, and no fetching is required.
ALL_PROJECTED_ATTRIBUTES - Allowed only when querying an index. Retrieves all attributes that have been projected into the index. If the index is configured to project all attributes, this return value is equivalent to specifying ALL_ATTRIBUTES .
COUNT - Returns the number of matching items, rather than the matching items themselves.
SPECIFIC_ATTRIBUTES - Returns only the attributes listed in AttributesToGet . This return value is equivalent to specifying AttributesToGet without specifying any value for Select . If you query a local secondary index and request only attributes that are projected into that index, the operation will read only the index and not the table. If any of the requested attributes are not projected into the local secondary index, DynamoDB will fetch each of these attributes from the parent table. This extra fetching incurs additional throughput cost and latency. If you query a global secondary index, you can only request attributes that are projected into the index. Global secondary index queries cannot fetch attributes from the parent table.
If neither Select nor AttributesToGet are specified, DynamoDB defaults to ALL_ATTRIBUTES when accessing a table, and ALL_PROJECTED_ATTRIBUTES when accessing an index. You cannot use both Select and AttributesToGet together in a single request, unless the value for Select is SPECIFIC_ATTRIBUTES . (This usage is equivalent to specifying AttributesToGet without any value for Select .)
Note
If you use the ProjectionExpression parameter, then the value for Select can only be SPECIFIC_ATTRIBUTES . Any other value for Select will return an error.
list
Warning
This is a legacy parameter, for backward compatibility. New applications should use ProjectionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
You cannot use both AttributesToGet and Select together in a Query request, unless the value for Select is SPECIFIC_ATTRIBUTES . (This usage is equivalent to specifying AttributesToGet without any value for Select .)
If you query a local secondary index and request only attributes that are projected into that index, the operation will read only the index and not the table. If any of the requested attributes are not projected into the local secondary index, DynamoDB will fetch each of these attributes from the parent table. This extra fetching incurs additional throughput cost and latency.
If you query a global secondary index, you can only request attributes that are projected into the index. Global secondary index queries cannot fetch attributes from the parent table.
(string) --
integer
The maximum number of items to evaluate (not necessarily the number of matching items). If DynamoDB processes the number of items up to the limit while processing the results, it stops the operation and returns the matching values up to that point, and a key in LastEvaluatedKey to apply in a subsequent operation, so that you can pick up where you left off. Also, if the processed data set size exceeds 1 MB before DynamoDB reaches this limit, it stops the operation and returns the matching values up to the limit, and a key in LastEvaluatedKey to apply in a subsequent operation to continue the operation. For more information, see Query and Scan in the Amazon DynamoDB Developer Guide .
boolean
A value that if set to true , then the operation uses strongly consistent reads; otherwise, eventually consistent reads are used.
Strongly consistent reads are not supported on global secondary indexes. If you query a global secondary index with ConsistentRead set to true , you will receive an error message.
dict
Warning
This is a legacy parameter, for backward compatibility. New applications should use KeyConditionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
The selection criteria for the query. For a query on a table, you can have conditions only on the table primary key attributes. You must provide the hash key attribute name and value as an EQ condition. You can optionally provide a second condition, referring to the range key attribute.
Note
If you don't provide a range key condition, all of the items that match the hash key will be retrieved. If a FilterExpression or QueryFilter is present, it will be applied after the items are retrieved.
For a query on an index, you can have conditions only on the index key attributes. You must provide the index hash attribute name and value as an EQ condition. You can optionally provide a second condition, referring to the index key range attribute.
Each KeyConditions element consists of an attribute name to compare, along with the following:
AttributeValueList - One or more values to evaluate against the supplied attribute. The number of values in the list depends on the ComparisonOperator being used. For type Number, value comparisons are numeric. String value comparisons for greater than, equals, or less than are based on ASCII character code values. For example, a is greater than A , and a is greater than B . For a list of code values, see http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters. For Binary, DynamoDB treats each byte of the binary data as unsigned when it compares binary values.
ComparisonOperator - A comparator for evaluating attributes, for example, equals, greater than, less than, and so on. For KeyConditions , only the following comparison operators are supported: EQ | LE | LT | GE | GT | BEGINS_WITH | BETWEEN The following are descriptions of these comparison operators.
EQ : Equal. 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 specified 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"]} .
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).
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 .
(string) --
(dict) --
Represents the selection criteria for a Query or Scan operation:
For a Query operation, Condition is used for specifying the KeyConditions to use when querying a table or an index. For KeyConditions , only the following comparison operators are supported: EQ | LE | LT | GE | GT | BEGINS_WITH | BETWEEN Condition is also used in a QueryFilter , which evaluates the query results and returns only the desired values.
For a Scan operation, Condition is used in a ScanFilter , which evaluates the scan results and returns only the desired values.
AttributeValueList (list) --
One or more values to evaluate against the supplied attribute. The number of values in the list depends on the ComparisonOperator being used.
For type Number, value comparisons are numeric.
String value comparisons for greater than, equals, or less than are based on ASCII character code values. For example, a is greater than A , and a is greater than B . For a list of code values, see http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters.
For Binary, DynamoDB treats each byte of the binary data as unsigned when it compares binary values.
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
S (string) --
A String data type.
N (string) --
A Number data type.
B (bytes) --
A Binary data type.
SS (list) --
A String Set data type.
(string) --
NS (list) --
A Number Set data type.
(string) --
BS (list) --
A Binary Set data type.
(bytes) --
M (dict) --
A Map of attribute values.
(string) --
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
L (list) --
A List of attribute values.
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
NULL (boolean) --
A Null data type.
BOOL (boolean) --
A Boolean data type.
ComparisonOperator (string) -- [REQUIRED]
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 datatypes, 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 datatypes, 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 datatypes, including lists and maps.
Note
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 datatypes, including lists and maps.
Note
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 within two sets. AttributeValueList can contain one or more AttributeValue elements of type String, Number, or Binary (not a set type). These attributes are compared against an existing set type attribute of an item. If any elements of the input set are present in 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 .
dict
Warning
This is a legacy parameter, for backward compatibility. New applications should use FilterExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
A condition that evaluates the query results after the items are read and returns only the desired values.
This parameter does not support attributes of type List or Map.
Note
A QueryFilter is applied after the items have already been read; the process of filtering does not consume any additional read capacity units.
If you provide more than one condition in the QueryFilter map, then by default all of the conditions must evaluate to true. In other words, the conditions are ANDed together. (You can use the ConditionalOperator parameter to OR the conditions instead. If you do this, then at least one of the conditions must evaluate to true, rather than all of them.)
Note that QueryFilter does not allow key attributes. You cannot define a filter condition on a hash key or range key.
Each QueryFilter element consists of an attribute name to compare, along with the following:
AttributeValueList - One or more values to evaluate against the supplied attribute. The number of values in the list depends on the operator specified in ComparisonOperator . For type Number, value comparisons are numeric. String value comparisons for greater than, equals, or less than are based on ASCII character code values. For example, a is greater than A , and a is greater than B . For a list of code values, see http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters. For type Binary, DynamoDB treats each byte of the binary data as unsigned when it compares binary values. For information on specifying data types in JSON, see JSON Data Format in the Amazon DynamoDB Developer Guide .
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 For complete descriptions of all comparison operators, see the Condition data type.
(string) --
(dict) --
Represents the selection criteria for a Query or Scan operation:
For a Query operation, Condition is used for specifying the KeyConditions to use when querying a table or an index. For KeyConditions , only the following comparison operators are supported: EQ | LE | LT | GE | GT | BEGINS_WITH | BETWEEN Condition is also used in a QueryFilter , which evaluates the query results and returns only the desired values.
For a Scan operation, Condition is used in a ScanFilter , which evaluates the scan results and returns only the desired values.
AttributeValueList (list) --
One or more values to evaluate against the supplied attribute. The number of values in the list depends on the ComparisonOperator being used.
For type Number, value comparisons are numeric.
String value comparisons for greater than, equals, or less than are based on ASCII character code values. For example, a is greater than A , and a is greater than B . For a list of code values, see http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters.
For Binary, DynamoDB treats each byte of the binary data as unsigned when it compares binary values.
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
S (string) --
A String data type.
N (string) --
A Number data type.
B (bytes) --
A Binary data type.
SS (list) --
A String Set data type.
(string) --
NS (list) --
A Number Set data type.
(string) --
BS (list) --
A Binary Set data type.
(bytes) --
M (dict) --
A Map of attribute values.
(string) --
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
L (list) --
A List of attribute values.
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
NULL (boolean) --
A Null data type.
BOOL (boolean) --
A Boolean data type.
ComparisonOperator (string) -- [REQUIRED]
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 datatypes, 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 datatypes, 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 datatypes, including lists and maps.
Note
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 datatypes, including lists and maps.
Note
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 within two sets. AttributeValueList can contain one or more AttributeValue elements of type String, Number, or Binary (not a set type). These attributes are compared against an existing set type attribute of an item. If any elements of the input set are present in 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 .
string
Warning
This is a legacy parameter, for backward compatibility. New applications should use FilterExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
A logical operator to apply to the conditions in a QueryFilter map:
AND - If all of the conditions evaluate to true, then the entire map evaluates to true.
OR - If at least one of the conditions evaluate to true, then the entire map evaluates to true.
If you omit ConditionalOperator , then AND is the default.
The operation will succeed only if the entire map evaluates to true.
Note
This parameter does not support attributes of type List or Map.
boolean
A value that specifies ascending (true) or descending (false) traversal of the index. DynamoDB returns results reflecting the requested order determined by the range key. If the data type is Number, the results are returned in numeric order. For type String, the results are returned in order of ASCII character code values. For type Binary, DynamoDB treats each byte of the binary data as unsigned when it compares binary values.
If ScanIndexForward is not specified, the results are returned in ascending order.
dict
The primary key of the first item that this operation will evaluate. Use the value that was returned for LastEvaluatedKey in the previous operation.
The data type for ExclusiveStartKey must be String, Number or Binary. No set data types are allowed.
(string) --
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
S (string) --
A String data type.
N (string) --
A Number data type.
B (bytes) --
A Binary data type.
SS (list) --
A String Set data type.
(string) --
NS (list) --
A Number Set data type.
(string) --
BS (list) --
A Binary Set data type.
(bytes) --
M (dict) --
A Map of attribute values.
(string) --
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
L (list) --
A List of attribute values.
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
NULL (boolean) --
A Null data type.
BOOL (boolean) --
A Boolean data type.
string
A value that if set to TOTAL , the response includes ConsumedCapacity data for tables and indexes. If set to INDEXES , the response includes ConsumedCapacity for indexes. If set to NONE (the default), ConsumedCapacity is not included in the response.
string
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 will be returned. If any of the requested attributes are not found, they will not appear in the result.
For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide .
Note
ProjectionExpression replaces the legacy AttributesToGet parameter.
string
A string that contains conditions that DynamoDB applies after the Query operation, but before the data is returned to you. Items that do not satisfy the FilterExpression criteria are not returned.
Note
A FilterExpression is applied after the items have already been read; the process of filtering does not consume any additional read capacity units.
For more information, see Filter Expressions in the Amazon DynamoDB Developer Guide .
Note
FilterExpression replaces the legacy QueryFilter and ConditionalOperator parameters.
string
The condition that specifies the key value(s) for items to be retrieved by the Query action.
The condition must perform an equality test on a single hash key value. The condition can also test for one or more range key values. A Query can use KeyConditionExpression to retrieve a single item with a given hash and range key value, or several items that have the same hash key value but different range key values.
The hash key equality test is required, and must be specified in the following format:
hashAttributeName = :hashval
If you also want to provide a range key condition, it must be combined using AND with the hash key condition. Following is an example, using the = comparison operator for the range key:
hashAttributeName = :hashval AND rangeAttributeName = :rangeval
Valid comparisons for the range key condition are as follows:
rangeAttributeName = :rangeval - true if the range key is equal to :rangeval .
rangeAttributeName < :rangeval - true if the range key is less than :rangeval .
rangeAttributeName <= :rangeval - true if the range key is less than or equal to :rangeval .
rangeAttributeName > :rangeval - true if the range key is greater than :rangeval .
rangeAttributeName >= :rangeval - true if the range key is greater than or equal to :rangeval .
rangeAttributeName BETWEEN :rangeval1 AND :rangeval2 - true if the range key is less than or greater than :rangeval1 , and less than or equal to :rangeval2 .
begins_with ( rangeAttributeName , :rangeval ) - true if the range key begins with a particular operand. Note that the function name begins_with is case-sensitive.
Use the ExpressionAttributeValues parameter to replace tokens such as :hashval and :rangeval with actual values at runtime.
You can optionally use the ExpressionAttributeNames parameter to replace the names of the hash and range attributes with placeholder tokens. This might be necessary if an attribute name conflicts with a DynamoDB reserved word. For example, the following KeyConditionExpression causes an error because Size is a reserved word:
Size = :myval
To work around this, define a placeholder (such a #myval ) to represent the attribute name Size . KeyConditionExpression then is as follows:
#S = :myval
For a list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide .
For more information on ExpressionAttributeNames and ExpressionAttributeValues , see Using Placeholders for Attribute Names and Values in the Amazon DynamoDB Developer Guide .
Note
KeyConditionExpression replaces the legacy KeyConditions parameter.
dict
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
Note
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 Using Placeholders for Attribute Names and Values in the Amazon DynamoDB Developer Guide .
(string) --
(string) --
dict
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 Using Placeholders for Attribute Names and Values in the Amazon DynamoDB Developer Guide .
(string) --
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
S (string) --
A String data type.
N (string) --
A Number data type.
B (bytes) --
A Binary data type.
SS (list) --
A String Set data type.
(string) --
NS (list) --
A Number Set data type.
(string) --
BS (list) --
A Binary Set data type.
(bytes) --
M (dict) --
A Map of attribute values.
(string) --
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
L (list) --
A List of attribute values.
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
NULL (boolean) --
A Null data type.
BOOL (boolean) --
A Boolean data type.
dict
Response Syntax
{
'Items': [
{
'string': {
'S': 'string',
'N': 'string',
'B': b'bytes',
'SS': [
'string',
],
'NS': [
'string',
],
'BS': [
b'bytes',
],
'M': {
'string': {'... recursive ...'}
},
'L': [
{'... recursive ...'},
],
'NULL': True|False,
'BOOL': True|False
}
},
],
'Count': 123,
'ScannedCount': 123,
'LastEvaluatedKey': {
'string': {
'S': 'string',
'N': 'string',
'B': b'bytes',
'SS': [
'string',
],
'NS': [
'string',
],
'BS': [
b'bytes',
],
'M': {
'string': {'... recursive ...'}
},
'L': [
{'... recursive ...'},
],
'NULL': True|False,
'BOOL': True|False
}
},
'ConsumedCapacity': {
'TableName': 'string',
'CapacityUnits': 123.0,
'Table': {
'CapacityUnits': 123.0
},
'LocalSecondaryIndexes': {
'string': {
'CapacityUnits': 123.0
}
},
'GlobalSecondaryIndexes': {
'string': {
'CapacityUnits': 123.0
}
}
}
}
Response Structure
(dict) --
Represents the output of a Query operation.
Items (list) --
An array of item attributes that match the query criteria. Each element in this array consists of an attribute name and the value for that attribute.
(dict) --
(string) --
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
S (string) --
A String data type.
N (string) --
A Number data type.
B (bytes) --
A Binary data type.
SS (list) --
A String Set data type.
(string) --
NS (list) --
A Number Set data type.
(string) --
BS (list) --
A Binary Set data type.
(bytes) --
M (dict) --
A Map of attribute values.
(string) --
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
L (list) --
A List of attribute values.
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
NULL (boolean) --
A Null data type.
BOOL (boolean) --
A Boolean data type.
Count (integer) --
The number of items in the response.
If you used a QueryFilter in the request, then Count is the number of items returned after the filter was applied, and ScannedCount is the number of matching items before> the filter was applied.
If you did not use a filter in the request, then Count and ScannedCount are the same.
ScannedCount (integer) --
The number of items evaluated, before any QueryFilter is applied. A high ScannedCount value with few, or no, Count results indicates an inefficient Query operation. For more information, see Count and ScannedCount in the Amazon DynamoDB Developer Guide .
If you did not use a filter in the request, then ScannedCount is the same as Count .
LastEvaluatedKey (dict) --
The primary key of the item where the operation stopped, inclusive of the previous result set. Use this value to start a new operation, excluding this value in the new request.
If LastEvaluatedKey is empty, then the "last page" of results has been processed and there is no more data to be retrieved.
If LastEvaluatedKey is not empty, it does not necessarily mean that there is more data in the result set. The only way to know when you have reached the end of the result set is when LastEvaluatedKey is empty.
(string) --
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
S (string) --
A String data type.
N (string) --
A Number data type.
B (bytes) --
A Binary data type.
SS (list) --
A String Set data type.
(string) --
NS (list) --
A Number Set data type.
(string) --
BS (list) --
A Binary Set data type.
(bytes) --
M (dict) --
A Map of attribute values.
(string) --
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
L (list) --
A List of attribute values.
(dict) --
Represents the data for an attribute. You can set one, and only one, of the elements.
Each attribute in an item is a name-value pair. An attribute can be single-valued or multi-valued set. For example, a book item can have title and authors attributes. Each book has one title but can have many authors. The multi-valued attribute is a set; duplicate values are not allowed.
NULL (boolean) --
A Null data type.
BOOL (boolean) --
A Boolean data type.
ConsumedCapacity (dict) --
The capacity units consumed by an operation. The data returned includes the total provisioned throughput consumed, along with statistics for the table and any indexes involved in the operation. ConsumedCapacity is only returned if the request asked for it. For more information, see Provisioned Throughput in the Amazon DynamoDB Developer Guide .
TableName (string) --
The name of the table that was affected by the operation.
CapacityUnits (float) --
The total number of capacity units consumed by the operation.
Table (dict) --
The amount of throughput consumed on the table affected by the operation.
CapacityUnits (float) --
The total number of capacity units consumed on a table or an index.
LocalSecondaryIndexes (dict) --
The amount of throughput consumed on each local index affected by the operation.
(string) --
(dict) --
Represents the amount of provisioned throughput capacity consumed on a table or an index.
CapacityUnits (float) --
The total number of capacity units consumed on a table or an index.
GlobalSecondaryIndexes (dict) --
The amount of throughput consumed on each global index affected by the operation.
(string) --
(dict) --
Represents the amount of provisioned throughput capacity consumed on a table or an index.
CapacityUnits (float) --
The total number of capacity units consumed on a table or an index.