[{
"forms": [{
"id": "52b55960-023e-11e7-9140-f3c1d163524b",
"title": "Default Form",
"update_history": [{
"version": "1",
"updated_at": "2016-12-10 12:12:10"
}, {
"version": "2",
"updated_at": "2017-01-01 05:17:19"
}, {
"version": "3",
"updated_at": "2017-02-07 03:22:39"
}, {
"version": "4",
"updated_at": "2017-03-03 02:28:56"
}, {
"version": "5",
"updated_at": "2017-01-11 07:01:22"
}]
}]
}]
I have above Json stored in Dynamo-DB table. forms object is parent object. I have stored form updated detail version and updated_at in update_history nested object. I want updated_at of version of 2. Please suggest me, what is wrong in below query. I got empty result.
`$response = $client->scan([
'TableName' => 'TableName',
'ProjectionExpression' => 'Json.forms.update_history.updated_at',
'ExpressionAttributeValues' => [
':val1' => ['S' => '52b55960-023e-11e7-9140-f3c1d163524b'],
':val2' => ['S' => '2']
],
'FilterExpression' => 'id = :val1 and Json.forms.update_history.version = :val2',
]);`
Please refer the DocumentPath example in the below link and try to use deference operator.
For a nested attribute, you construct the document path using dereference operators.
If you don't know the deference operator (i.e. index), you can't filter the data as you have tried.
Example:-
Accessing List Elements:-
MyList[0]
AnotherList[12]
ThisList[5][11]
Accessing Map Elements:-
MyMap.nestedField
MyMap.nestedField.deeplyNestedField
You have the combination of both Map and List, you need to FilterExpression accordingly.