Tasks

•   tableName

  The name of the table containing the requested items.

  Constraints:
  Length: 3 – 255
  Pattern: [a-zA-Z0-9_.–]+
  

  property
•   attributesToGet

  The names of one or more attributes to retrieve. 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.

  Constraints:
  Length: 1 –
  

  property
•   limit

  The maximum number of items to evaluate (not necessarily the number of matching items). If Amazon 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 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 Amazon DynamoDB reaches this limit, it stops the operation and returns the matching values up to the limit, and a LastEvaluatedKey to apply in a subsequent operation to continue the operation. For more information see Query and Scan of the Amazon DynamoDB Developer Guide.

  Constraints:
  Range: 1 –
  

  property
•   select

  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. For a table, this is the default. For an index, this mode causes Amazon DynamoDB to fetch the full item from the table for each matching item in the index. If the index is configured to project all item attributes, the matching items will not be fetched from the table. Fetching items from the table incurs additional throughput cost and latency.

  • ALL_PROJECTED_ATTRIBUTES: Retrieves all attributes which have been projected into the index. If the index is configured to project all attributes, this 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 is equivalent to specifying AttributesToGet without specifying any value for Select.

    If you are querying an index and only request attributes that are projected into that index, the operation will consult the index and bypass the table. If any of the requested attributes are not projected into the index, Amazon DynamoDB will need to fetch each matching item from the table. This extra fetching incurs additional throughput cost and latency.

  When neither Select nor AttributesToGet are specified, Amazon 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.)

  Constraints:
  Allowed Values: ALL_ATTRIBUTES, ALL_PROJECTED_ATTRIBUTES, SPECIFIC_ATTRIBUTES, COUNT

  property
•   scanFilter

  Evaluates the scan results and returns only the desired values. Multiple conditions are treated as “AND” operations: all conditions must be met to be included in the results.

  Each ScanConditions element consists of an attribute name to compare, along with the following:

  • AttributeValueList-One or more values to evaluate against the supplied attribute. This list contains exactly one value, except for a BETWEEN or IN comparison, in which case the list contains two values.

    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 aa is greater than B. For a list of code values, see http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters.

    For Binary, Amazon DynamoDB treats each byte of the binary data as unsigned when it compares binary values, for example when evaluating query expressions.

  • ComparisonOperator-A comparator for evaluating attributes. For example, equals, greater than, less than, etc.

    Valid comparison operators for Scan:

    EQ | NE | LE | LT | GE | GT | NOT_NULL | NULL | CONTAINS | NOT_CONTAINS | BEGINS_WITH | IN | BETWEEN

    For information on specifying data types in JSON, see JSON Data Format of the Amazon DynamoDB Developer Guide.

    The following are descriptions of each comparison operator.

    • EQ : Equal.

      AttributeValueList can contain only one AttributeValue of type String, Number, or Binary (not a set). If an item contains an AttributeValue 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”]}.

    • NE : Not equal.

      AttributeValueList can contain only one AttributeValue of type String, Number, or Binary (not a set). If an item contains an AttributeValue 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 of type String, Number, or Binary (not a set). If an item contains an AttributeValue 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 compare to {“NS”:[“6”, “2”, “1”]}.

    • LT : Less than.

      AttributeValueList can contain only one AttributeValue of type String, Number, or Binary (not a set). If an item contains an AttributeValue 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 compare to {“NS”:[“6”, “2”, “1”]}.

    • GE : Greater than or equal.

      AttributeValueList can contain only one AttributeValue of type String, Number, or Binary (not a set). If an item contains an AttributeValue 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 compare to {“NS”:[“6”, “2”, “1”]}.

    • GT : Greater than.

      AttributeValueList can contain only one AttributeValue of type String, Number, or Binary (not a set). If an item contains an AttributeValue 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 compare to {“NS”:[“6”, “2”, “1”]}.

    • NOT_NULL : The attribute exists.

    • NULL : The attribute does not exist.

    • CONTAINS : checks for a subsequence, or value in a set.

      AttributeValueList can contain only one AttributeValue of type String, Number, or Binary (not a set). If the target attribute of the comparison is a String, then the operation checks for a substring match. If the target attribute of the comparison is Binary, then the operation 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 operation checks for a member of the set (not as a substring).

    • NOT_CONTAINS : checks for absence of a subsequence, or absence of a value in a set.

      AttributeValueList can contain only one AttributeValue of type String, Number, or Binary (not a set). If the target attribute of the comparison is a String, then the operation checks for the absence of a substring match. If the target attribute of the comparison is Binary, then the operation 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 operation checks for the absence of a member of the set (not as a substring).

    • BEGINS_WITH : checks for a prefix.

      AttributeValueList can contain only one AttributeValue of type String or Binary (not a Number or a set). The target attribute of the comparison must be a String or Binary (not a Number or a set).

    • IN : checks for exact matches.

      AttributeValueList can contain more than one AttributeValue of type String, Number, or Binary (not a set). The target attribute of the comparison must be of the same type and exact value to match. A String never matches a String set.

    • 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). 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 of a different type than the one specified 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”]}

  property
•   exclusiveStartKey

  The primary key of the item from which to continue an earlier operation. An earlier operation might provide this value as the LastEvaluatedKey if that operation was interrupted before completion; either because of the result set size or because of the setting for Limit. The LastEvaluatedKey can be passed back in a new request to continue the operation from that point.

  The data type for ExclusiveStartKey must be String, Number or Binary. No set data types are allowed.

  property
•   returnConsumedCapacity

  Determines whether to include consumed capacity information in the output. If this is set to TOTAL, then this information is shown in the output; otherwise, the consumed capacity information is not shown.

  Constraints:
  Allowed Values: TOTAL, NONE

  property
• – init

  Default constructor for a new ScanRequest object. Callers should use the property methods to initialize this object after creating it.

• – initWithTableName:

  Constructs a new ScanRequest object. Callers should use properties to initialize any additional object members.

• – addAttributesToGet:

  Adds a single object to attributesToGet. This function will alloc and init attributesToGet if not already done.

• – setScanFilterValue:forKey:

  Set a value in the dictionary scanFilter for the specified key. This function will alloc and init scanFilter if not already done.

• – setExclusiveStartKeyValue:forKey:

  Set a value in the dictionary exclusiveStartKey for the specified key. This function will alloc and init exclusiveStartKey if not already done.

• – description

  Returns a string representation of this object; useful for testing and debugging.