Retrieve Item(Query)

Operation Name

Retrieve Item(Query)

Function Overview

Retrieves item stored in Amazon DynamoDB table.

In this operation, Query API is available. Refer to the following page about API specification.

Data Model

Table model type.

Properties

For the use of variables, refer to "Variable".
Basic settings
Item name Required/Optional Use of variables Description Remarks
Name Required Not available Enter the name to show on the script canvas.  
Required settings
Item name Required/Optional Use of variables Description Remarks
Destination Required Not available Select a global resource.
  • [Add]:
    Adds a new global resource.
  • [Edit list]:
    Enables to edit the global resource setting on " Resource edit list" screen.
  
Table name Required Available Select or enter the name of reading table name.  
Index name Required Available Select or enter the name of reading index.  
Attribute list Required - Specifies index attribute list specified in [Index name].
Added row becomes read targeted column.

Each read targeted column can be operated with the following button.
  • [Add]:
    Adds a read targeted column.
  • [Up]:
    Moves the order of the selected read targeted column upwards by one.
  • [Down]:
    Moves the order of the selected read targeted column downwards by one.
  • [Delete]:
    Deletes a read targeted column.
  
Attribute list/Hash key Optional Not available Shows whether or not the table specified in [Table name] or hash key attribute of index specified in [Index name].  
Attribute list/Range key Optional Not available Shows whether or not the range key attribute of the table specified in [Table name] or index specified in [Index name].  
Attribute list/Attribute name Required Available Enters attribute name of table specified in [Table name] or attribute name of index specified in [Index name].
  • Specified attribute name is showed to Mapper schema.
Attribute list/Type Required Not available Select [Attribute name] type.
  • Showed in "<DynamoDB data type> (<Inner data type>)" format.
    • DynamoDB data type:
      Data type supported by Amazon DynamoDB.
    • Inner data type:
      Data type used in inner DataSpider.
      For details, refer to "Inner data type".
Hash key value Required Available Enter attribute value of hash key to specify as Query.  
Property action
Item name Description Remarks
Update table name list Gets table name in the specified destination and set to [Table name].  
Update index name list Gets index set to specified table and set to [Index name].  
Update attribute list Update attribute list of index specified in [Index name].
  • Enabled, if [Index name] is specified.
  • Extracts attribute name and data type from item received implementing Scan, to table specified in [Table name], or index specified in [Index name].
  • If unsupported DynamoDB data type attribute exists in the received item by Scan, the attribute is not added to attribute list.
    • For supported type, refer to "Amazon DynamoDB Adapter Restriction".
  • If item does not exist to table specified in [Table name], sets primary key only.
    Also, data type sets [String (String)] regardless of the actual attribute type.
Range key settings
Item name Required/Optional Use of variables Description Remarks
Range key condition Required Not available Specifies range key attribute condition to specify as Query.
  • [EQUAL TO]:(default)
    Extracts items that have Range key value which equals to the value specified in [Range key value].
  • [LESS THAN]:
    Extracts items that have Range key value which is less than the value specified in [Range key value].
  • [LESS THAN OR EQUAL TO]:
    Extracts items that have Range key value which is below the value specified in [Range key value].
  • [GREATER THAN]:
    Extracts items that have Range key value which is more than the value specified in [Range key value].
  • [GREATER THAN OR EQUAL TO]:
    Extracts items that have Range key value which is above the value specified in [Range key value].
  • [BEGINS WITH]:
    Extracts items that have String type or Binary type Range key value which starts with values specified in [Range key value].
  • [BETWEEN]:
    Extracts items that have Range key value which is more than the value specified in [Range key start value] and less than the value specified in [Range key end value].
  
Range key value Optional Available Specifies range key attribute value to set as Query.  
Range key start value Optional Available Specifies start value of range key attribute to set as Query.
  • Showed, if [BETWEEN] is selected to [Range key condition].
Range key end value Optional Available Specifies end value of range key attribute to set as Query.
  • Showed, if [BETWEEN] is selected to [Range key condition].
Read settings
Item name Required/Optional Use of variables Description Remarks
Strongly consistent reads Required Not available Select whether to read with strong strongly consistent reads.  
Skip rows, if actual type and attribute list type differ Required Not available Select whether to skip the item or not if type specified in [Attribute list/Type] and the actually received type differ.
  • Skipped item information is output to script execution log.
Data processing method
Item name Required/Optional Use of variables Description Remarks
Data Processing method Required Not available Select a data processing method.
  • [Use script settings]:(default)
    Applies the setting of mass data processing setup in script property to the adapter.
  • [Disable]:
    Does not perform mass data processing.
  • [Enable]:
    Performs mass data processing.
  
Comment
Item name Required/Optional Use of variables Description Remarks
Comment Optional Not available You can write a short description of this adapter.
The description will be reflected in the specifications.		  

Schema

Input Schema

None.

Output Schema

Column number differs depending on the setting of [Attribute list].
For details on schema structure, refer to "Table model type schema".

Loading Schema on Mapper

Schema is loaded automatically.
For details, refer to "Edit Schema".

Mass data processing

Mass data processing is supported.

PSP Usage

PSP is supported.
For details on PSP, refer to "Parallel Stream Processing".

Available Component Variable

Component variable name Description Remarks
count Stores the number of received item.
  • Default value is null.
skip_count Stores the skipped item number if type specified in attribute list and the actual type differ.
  • Default value is null.
message_category Stores the category of message code corresponding to the occurred error.
  • Default value is null.
message_code Stores the code of message code corresponding to the occurred error.
  • Default value is null.
message_level Stores the severity of message code corresponding to the occurred error.
  • Default value is null.
error_type Stores the error type of occurred error.
  • Default value is null.
  • Error is represented in the format depicted below.
    Example:java.io.FileNotFoundException
  • The value may vary depending on the DataSpider Servista version.
error_message Stores the error message of occurred error.
  • Default value is null.
  • The value may vary depending on the DataSpider Servista version.
error_trace Stores the trace information of occurred error.
  • Default value is null.
  • The value may vary depending on the DataSpider Servista version or the client application used.

Specification Limits

For specification limits common to each operations, refer to "Amazon DynamoDB Adapter Restriction".

Main Exceptions

Exception name Cause Solution
ResourceNotFoundException
Resource definition could not be found. Name:[]		 [Destination] is not specified. Specify [Destination].
ResourceNotFoundException
Resource definition could not be found. Name:[<Global resource name>]		 Resource definition specified in [Destination] is not found. Check global resource specified in [Destination].
InvalidPropertyConfigurationException
<Property name> is not specified.		 [<Property name>] is not specified. Specify [<Property name>].
UnexpectedDynamoDBDataTypeException
Data type differs.		 Type specified in [Attribute list/type] and the actually received attribute type differ. Exception can be restricted by putting attribute data that exist to table in order, or [Skips the row if actual type and attribute list type differ] is [Checked].

Notes