Class: Aws::DynamoDB::Types::ScanInput
- Inherits:
-
Struct
- Object
- Struct
- Aws::DynamoDB::Types::ScanInput
- Defined in:
- gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb
Overview
Represents the input of a Scan
operation.
Constant Summary collapse
- SENSITIVE =
[]
Instance Attribute Summary collapse
-
#attributes_to_get ⇒ Array<String>
This is a legacy parameter.
-
#conditional_operator ⇒ String
This is a legacy parameter.
-
#consistent_read ⇒ Boolean
A Boolean value that determines the read consistency model during the scan:.
-
#exclusive_start_key ⇒ Hash<String,Types::AttributeValue>
The primary key of the first item that this operation will evaluate.
-
#expression_attribute_names ⇒ Hash<String,String>
One or more substitution tokens for attribute names in an expression.
-
#expression_attribute_values ⇒ Hash<String,Types::AttributeValue>
One or more values that can be substituted in an expression.
-
#filter_expression ⇒ String
A string that contains conditions that DynamoDB applies after the
Scan
operation, but before the data is returned to you. -
#index_name ⇒ String
The name of a secondary index to scan.
-
#limit ⇒ Integer
The maximum number of items to evaluate (not necessarily the number of matching items).
-
#projection_expression ⇒ String
A string that identifies one or more attributes to retrieve from the specified table or index.
-
#return_consumed_capacity ⇒ String
Determines the level of detail about either provisioned or on-demand throughput consumption that is returned in the response:.
-
#scan_filter ⇒ Hash<String,Types::Condition>
This is a legacy parameter.
-
#segment ⇒ Integer
For a parallel
Scan
request,Segment
identifies an individual segment to be scanned by an application worker. -
#select ⇒ String
The attributes to be returned in the result.
-
#table_name ⇒ String
The name of the table containing the requested items or if you provide
IndexName
, the name of the table to which that index belongs. -
#total_segments ⇒ Integer
For a parallel
Scan
request,TotalSegments
represents the total number of segments into which theScan
operation will be divided.
Instance Attribute Details
#attributes_to_get ⇒ Array<String>
This is a legacy parameter. Use ProjectionExpression
instead. For
more information, see AttributesToGet in the Amazon DynamoDB
Developer Guide.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#conditional_operator ⇒ String
This is a legacy parameter. Use FilterExpression
instead. For more
information, see ConditionalOperator in the Amazon DynamoDB
Developer Guide.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#consistent_read ⇒ Boolean
A Boolean value that determines the read consistency model during the scan:
If
ConsistentRead
isfalse
, then the data returned fromScan
might not contain the results from other recently completed write operations (PutItem
,UpdateItem
, orDeleteItem
).If
ConsistentRead
istrue
, then all of the write operations that completed before theScan
began are guaranteed to be contained in theScan
response.
The default setting for ConsistentRead
is false
.
The ConsistentRead
parameter is not supported on global secondary
indexes. If you scan a global secondary index with ConsistentRead
set to true, you will receive a ValidationException
.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#exclusive_start_key ⇒ Hash<String,Types::AttributeValue>
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.
In a parallel scan, a Scan
request that includes
ExclusiveStartKey
must specify the same segment whose previous
Scan
returned the corresponding value of LastEvaluatedKey
.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#expression_attribute_names ⇒ Hash<String,String>
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
^
For more information on expression attribute names, see Specifying Item Attributes in the Amazon DynamoDB Developer Guide.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#expression_attribute_values ⇒ Hash<String,Types::AttributeValue>
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.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#filter_expression ⇒ String
A string that contains conditions that DynamoDB applies after the
Scan
operation, but before the data is returned to you. Items that
do not satisfy the FilterExpression
criteria are not returned.
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.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#index_name ⇒ String
The name of a secondary index to scan. This index can be any local
secondary index or global secondary index. Note that if you use the
IndexName
parameter, you must also provide TableName
.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#limit ⇒ 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 dataset 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 Working with Queries
in the Amazon DynamoDB Developer Guide.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#projection_expression ⇒ String
A string that identifies one or more attributes to retrieve from the specified table or index. 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 Specifying Item Attributes in the Amazon DynamoDB Developer Guide.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#return_consumed_capacity ⇒ String
Determines the level of detail about either provisioned or on-demand throughput consumption that is returned in the response:
INDEXES
- The response includes the aggregateConsumedCapacity
for the operation, together withConsumedCapacity
for each table and secondary index that was accessed.Note that some operations, such as
GetItem
andBatchGetItem
, do not access any indexes at all. In these cases, specifyingINDEXES
will only returnConsumedCapacity
information for table(s).TOTAL
- The response includes only the aggregateConsumedCapacity
for the operation.NONE
- NoConsumedCapacity
details are included in the response.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#scan_filter ⇒ Hash<String,Types::Condition>
This is a legacy parameter. Use FilterExpression
instead. For more
information, see ScanFilter in the Amazon DynamoDB Developer
Guide.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#segment ⇒ Integer
For a parallel Scan
request, Segment
identifies an individual
segment to be scanned by an application worker.
Segment IDs are zero-based, so the first segment is always 0. For
example, if you want to use four application threads to scan a table
or an index, then the first thread specifies a Segment
value of 0,
the second thread specifies 1, and so on.
The value of LastEvaluatedKey
returned from a parallel Scan
request must be used as ExclusiveStartKey
with the same segment ID
in a subsequent Scan
operation.
The value for Segment
must be greater than or equal to 0, and less
than the value provided for TotalSegments
.
If you provide Segment
, you must also provide TotalSegments
.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#select ⇒ 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 fetches 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 specifyingALL_ATTRIBUTES
.COUNT
- Returns the number of matching items, rather than the matching items themselves. Note that this uses the same quantity of read capacity units as getting the items, and is subject to the same item size calculations.SPECIFIC_ATTRIBUTES
- Returns only the attributes listed inProjectionExpression
. This return value is equivalent to specifyingProjectionExpression
without specifying any value forSelect
.If you query or scan a local secondary index and request only attributes that are projected into that index, the operation reads only the index and not the table. If any of the requested attributes are not projected into the local secondary index, DynamoDB fetches each of these attributes from the parent table. This extra fetching incurs additional throughput cost and latency.
If you query or scan 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 ProjectionExpression
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 ProjectionExpression
together in a single
request, unless the value for Select
is SPECIFIC_ATTRIBUTES
.
(This usage is equivalent to specifying ProjectionExpression
without any value for Select
.)
ProjectionExpression
parameter, then the value for
Select
can only be SPECIFIC_ATTRIBUTES
. Any other value for
Select
will return an error.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#table_name ⇒ String
The name of the table containing the requested items or if you
provide IndexName
, the name of the table to which that index
belongs.
You can also provide the Amazon Resource Name (ARN) of the table in this parameter.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |
#total_segments ⇒ Integer
For a parallel Scan
request, TotalSegments
represents the total
number of segments into which the Scan
operation will be divided.
The value of TotalSegments
corresponds to the number of
application workers that will perform the parallel scan. For
example, if you want to use four application threads to scan a table
or an index, specify a TotalSegments
value of 4.
The value for TotalSegments
must be greater than or equal to 1,
and less than or equal to 1000000. If you specify a TotalSegments
value of 1, the Scan
operation will be sequential rather than
parallel.
If you specify TotalSegments
, you must also specify Segment
.
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# File 'gems/aws-sdk-dynamodb/lib/aws-sdk-dynamodb/types.rb', line 8322 class ScanInput < Struct.new( :table_name, :index_name, :attributes_to_get, :limit, :select, :scan_filter, :conditional_operator, :exclusive_start_key, :return_consumed_capacity, :total_segments, :segment, :projection_expression, :filter_expression, :expression_attribute_names, :expression_attribute_values, :consistent_read) SENSITIVE = [] include Aws::Structure end |