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PowerBuilder

DynamoDB - Query

See more Amazon DynamoDB Examples

The Query operation finds items based on primary key values. You can query any table or secondary index that has a composite primary key (a partition key and a sort key).

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integer li_rc
integer li_Success
oleobject loo_Rest
oleobject loo_AuthAws
integer li_BTls
integer li_Port
integer li_BAutoReconnect
oleobject loo_Json
oleobject loo_SbRequestBody
oleobject loo_SbResponseBody
integer li_RespStatusCode
oleobject loo_JsonResponse
string ls_ReplyDateTimeS
string ls_PostedByS
string ls_IdS
integer li_ConsumedCapacityCapacityUnits
string ls_ConsumedCapacityTableName
integer li_Count
integer li_ScannedCount
integer i
integer li_Count_i

li_Success = 0

loo_Rest = create oleobject
li_rc = loo_Rest.ConnectToNewObject("Chilkat.Rest")
if li_rc < 0 then
    destroy loo_Rest
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// Implements the following CURL command:

// curl -X POST https://dynamodb.us-west-2.amazonaws.com/ \
//   -H "Accept-Encoding: identity" \
//   -H "Content-Type: application/x-amz-json-1.0" \
//   -H "Authorization: AWS4-HMAC-SHA256 Credential=<Credential>, SignedHeaders=<Headers>, Signature=<Signature>" \
//   -H "X-Amz-Date: <Date>" \
//   -H "X-Amz-Target: DynamoDB_20120810.Query" \
//   -d '{
//     "TableName": "Reply",
//     "IndexName": "PostedBy-Index",
//     "Limit": 3,
//     "ConsistentRead": true,
//     "ProjectionExpression": "Id, PostedBy, ReplyDateTime",
//     "KeyConditionExpression": "Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b",
//     "ExpressionAttributeValues": {
//         ":v1": {"S": "Amazon DynamoDB#DynamoDB Thread 1"},
//         ":v2a": {"S": "User A"},
//         ":v2b": {"S": "User C"}
//     },
//     "ReturnConsumedCapacity": "TOTAL"
// }'

// Use the following online tool to generate REST code from a CURL command
// Convert a cURL Command to REST Source Code

loo_AuthAws = create oleobject
li_rc = loo_AuthAws.ConnectToNewObject("Chilkat.AuthAws")

loo_AuthAws.AccessKey = "AWS_ACCESS_KEY"
loo_AuthAws.SecretKey = "AWS_SECRET_KEY"
// Don't forget to change the region to your particular region. (Also make the same change in the call to Connect below.)
loo_AuthAws.Region = "us-west-2"
loo_AuthAws.ServiceName = "dynamodb"
// SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
loo_Rest.SetAuthAws(loo_AuthAws)

// URL: https://dynamodb.us-west-2.amazonaws.com/
li_BTls = 1
li_Port = 443
li_BAutoReconnect = 1
li_Success = loo_Rest.Connect("dynamodb.us-west-2.amazonaws.com",li_Port,li_BTls,li_BAutoReconnect)
if li_Success <> 1 then
    Write-Debug "ConnectFailReason: " + string(loo_Rest.ConnectFailReason)
    Write-Debug loo_Rest.LastErrorText
    destroy loo_Rest
    destroy loo_AuthAws
    return
end if

// Note: The above code does not need to be repeatedly called for each REST request.
// The rest object can be setup once, and then many requests can be sent.  Chilkat will automatically
// reconnect within a FullRequest* method as needed.  It is only the very first connection that is explicitly
// made via the Connect method.

// Use this online tool to generate code from sample JSON:
// Generate Code to Create JSON

// The following JSON is sent in the request body.

// {
//   "TableName": "Reply",
//   "IndexName": "PostedBy-Index",
//   "Limit": 3,
//   "ConsistentRead": true,
//   "ProjectionExpression": "Id, PostedBy, ReplyDateTime",
//   "KeyConditionExpression": "Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b",
//   "ExpressionAttributeValues": {
//     ":v1": {
//       "S": "Amazon DynamoDB#DynamoDB Thread 1"
//     },
//     ":v2a": {
//       "S": "User A"
//     },
//     ":v2b": {
//       "S": "User C"
//     }
//   },
//   "ReturnConsumedCapacity": "TOTAL"
// }

loo_Json = create oleobject
li_rc = loo_Json.ConnectToNewObject("Chilkat.JsonObject")

loo_Json.UpdateString("TableName","Reply")
loo_Json.UpdateString("IndexName","PostedBy-Index")
loo_Json.UpdateInt("Limit",3)
loo_Json.UpdateBool("ConsistentRead",1)
loo_Json.UpdateString("ProjectionExpression","Id, PostedBy, ReplyDateTime")
loo_Json.UpdateString("KeyConditionExpression","Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b")
loo_Json.UpdateString("ExpressionAttributeValues.:v1.S","Amazon DynamoDB#DynamoDB Thread 1")
loo_Json.UpdateString("ExpressionAttributeValues.:v2a.S","User A")
loo_Json.UpdateString("ExpressionAttributeValues.:v2b.S","User C")
loo_Json.UpdateString("ReturnConsumedCapacity","TOTAL")

loo_Rest.AddHeader("Content-Type","application/x-amz-json-1.0")
loo_Rest.AddHeader("X-Amz-Target","DynamoDB_20120810.Query")
loo_Rest.AddHeader("Accept-Encoding","identity")

loo_SbRequestBody = create oleobject
li_rc = loo_SbRequestBody.ConnectToNewObject("Chilkat.StringBuilder")

loo_Json.EmitSb(loo_SbRequestBody)
loo_SbResponseBody = create oleobject
li_rc = loo_SbResponseBody.ConnectToNewObject("Chilkat.StringBuilder")

li_Success = loo_Rest.FullRequestSb("POST","/",loo_SbRequestBody,loo_SbResponseBody)
if li_Success <> 1 then
    Write-Debug loo_Rest.LastErrorText
    destroy loo_Rest
    destroy loo_AuthAws
    destroy loo_Json
    destroy loo_SbRequestBody
    destroy loo_SbResponseBody
    return
end if

li_RespStatusCode = loo_Rest.ResponseStatusCode
Write-Debug "response status code = " + string(li_RespStatusCode)
if li_RespStatusCode >= 400 then
    Write-Debug "Response Status Code = " + string(li_RespStatusCode)
    Write-Debug "Response Header:"
    Write-Debug loo_Rest.ResponseHeader
    Write-Debug "Response Body:"
    Write-Debug loo_SbResponseBody.GetAsString()
    destroy loo_Rest
    destroy loo_AuthAws
    destroy loo_Json
    destroy loo_SbRequestBody
    destroy loo_SbResponseBody
    return
end if

loo_JsonResponse = create oleobject
li_rc = loo_JsonResponse.ConnectToNewObject("Chilkat.JsonObject")

loo_JsonResponse.LoadSb(loo_SbResponseBody)

loo_JsonResponse.EmitCompact = 0
Write-Debug loo_JsonResponse.Emit()

// Sample JSON response:
// (Sample code for parsing the JSON response is shown below)

// {
//   "ConsumedCapacity": {
//     "CapacityUnits": 1,
//     "TableName": "Reply"
//   },
//   "Count": 2,
//   "Items": [
//     {
//       "ReplyDateTime": {
//         "S": "2015-02-18T20:27:36.165Z"
//       },
//       "PostedBy": {
//         "S": "User A"
//       },
//       "Id": {
//         "S": "Amazon DynamoDB#DynamoDB Thread 1"
//       }
//     },
//     {
//       "ReplyDateTime": {
//         "S": "2015-02-25T20:27:36.165Z"
//       },
//       "PostedBy": {
//         "S": "User B"
//       },
//       "Id": {
//         "S": "Amazon DynamoDB#DynamoDB Thread 1"
//       }
//     }
//   ],
//   "ScannedCount": 2
// }

// Sample code for parsing the JSON response...
// Use the following online tool to generate parsing code from sample JSON:
// Generate Parsing Code from JSON

li_ConsumedCapacityCapacityUnits = loo_JsonResponse.IntOf("ConsumedCapacity.CapacityUnits")
ls_ConsumedCapacityTableName = loo_JsonResponse.StringOf("ConsumedCapacity.TableName")
li_Count = loo_JsonResponse.IntOf("Count")
li_ScannedCount = loo_JsonResponse.IntOf("ScannedCount")
i = 0
li_Count_i = loo_JsonResponse.SizeOfArray("Items")
do while i < li_Count_i
    loo_JsonResponse.I = i
    ls_ReplyDateTimeS = loo_JsonResponse.StringOf("Items[i].ReplyDateTime.S")
    ls_PostedByS = loo_JsonResponse.StringOf("Items[i].PostedBy.S")
    ls_IdS = loo_JsonResponse.StringOf("Items[i].Id.S")
    i = i + 1
loop


destroy loo_Rest
destroy loo_AuthAws
destroy loo_Json
destroy loo_SbRequestBody
destroy loo_SbResponseBody
destroy loo_JsonResponse