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// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
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/**
* Before running this C++ code example, set up your development environment, including your credentials.
*
* For more information, see the following documentation topic:
*
* https://docs.aws.amazon.com/sdk-for-cpp/v1/developer-guide/getting-started.html
*
* For information on the structure of the code examples and how to build and run the examples, see
* https://docs.aws.amazon.com/sdk-for-cpp/v1/developer-guide/getting-started-code-examples.html.
*
**/
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# include <aws/core/Aws.h>
# include <aws/dynamodb/DynamoDBClient.h>
# include <aws/dynamodb/model/AttributeDefinition.h>
# include <aws/dynamodb/model/ScanRequest.h>
# include <iostream>
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# include "dynamodb_samples.h"
// snippet-start:[dynamodb.cpp.scan_table.code]
//! Scan an Amazon DynamoDB table.
/*!
\sa scanTable()
\param tableName: Name for the DynamoDB table.
\param projectionExpression: An optional projection expression, ignored if empty.
\param clientConfiguration: AWS client configuration.
\return bool: Function succeeded.
*/
bool AwsDoc : : DynamoDB : : scanTable ( const Aws : : String & tableName ,
const Aws : : String & projectionExpression ,
const Aws : : Client : : ClientConfiguration & clientConfiguration ) {
Aws : : DynamoDB : : DynamoDBClient dynamoClient ( clientConfiguration ) ;
Aws : : DynamoDB : : Model : : ScanRequest request ;
request . SetTableName ( tableName ) ;
if ( ! projectionExpression . empty ( ) )
request . SetProjectionExpression ( projectionExpression ) ;
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Aws : : Vector < Aws : : Map < Aws : : String , Aws : : DynamoDB : : Model : : AttributeValue > > all_items ;
Aws : : Map < Aws : : String , Aws : : DynamoDB : : Model : : AttributeValue > last_evaluated_key ; // Used for pagination;
do {
if ( ! last_evaluated_key . empty ( ) ) {
request . SetExclusiveStartKey ( last_evaluated_key ) ;
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}
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const Aws : : DynamoDB : : Model : : ScanOutcome & outcome = dynamoClient . Scan ( request ) ;
if ( outcome . IsSuccess ( ) ) {
// Reference the retrieved items.
const Aws : : Vector < Aws : : Map < Aws : : String , Aws : : DynamoDB : : Model : : AttributeValue > > & items = outcome . GetResult ( ) . GetItems ( ) ;
all_items . insert ( all_items . end ( ) , items . begin ( ) , items . end ( ) ) ;
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last_evaluated_key = outcome . GetResult ( ) . GetLastEvaluatedKey ( ) ;
}
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else {
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std : : cerr < < " Failed to Scan items: " < < outcome . GetError ( ) . GetMessage ( )
< < std : : endl ;
return false ;
}
} while ( ! last_evaluated_key . empty ( ) ) ;
if ( ! all_items . empty ( ) ) {
std : : cout < < " Number of items retrieved from scan: " < < all_items . size ( )
< < std : : endl ;
// Iterate each item and print.
for ( const Aws : : Map < Aws : : String , Aws : : DynamoDB : : Model : : AttributeValue > & itemMap : all_items ) {
std : : cout < < " ****************************************************** "
< < std : : endl ;
// Output each retrieved field and its value.
for ( const auto & itemEntry : itemMap )
std : : cout < < itemEntry . first < < " : " < < itemEntry . second . GetS ( )
< < std : : endl ;
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}
}
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else {
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std : : cout < < " No items found in table: " < < tableName < < std : : endl ;
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}
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return true ;
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}
// snippet-end:[dynamodb.cpp.scan_table.code]
/*
* main function
*
* Usage: 'run_scan_table <table> [projection_expression]'
*
* Prerequisites: Create a pre-populated DynamoDB table.
*
* For instructions on populating a table with sample data, see
* https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/SampleData.html.
*
*/
# ifndef TESTING_BUILD
int main ( int argc , char * * argv ) {
if ( argc < 2 ) {
std : : cout < < R " (
Usage :
run_scan_table < table > [ projection_expression ]
Where :
table - The table to scan .
To limit the fields returned from the table , add
an optional projection expression ( a quote - delimited ,
comma - separated list of attributes to retrieve ) .
) " ;
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return 1 ;
}
Aws : : SDKOptions options ;
Aws : : InitAPI ( options ) ;
{
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const Aws : : String tableName = ( argv [ 1 ] ) ;
const Aws : : String projectionExpression ( argc > 2 ? argv [ 2 ] : " " ) ;
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Aws : : Client : : ClientConfiguration clientConfig ;
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// Optional: Set to the AWS Region (overrides config file).
// clientConfig.region = "us-east-1";
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AwsDoc : : DynamoDB : : scanTable ( tableName , projectionExpression , clientConfig ) ;
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}
Aws : : ShutdownAPI ( options ) ;
return 0 ;
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}
# endif // TESTING_BUILD
