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PowerBuilder

DynamoDB - UpdateItem

See more Amazon DynamoDB Examples

Edits an existing item's attributes, or adds a new item to the table if it does not already exist. You can put, delete, or add attribute values. You can also perform a conditional update on an existing item (insert a new attribute name-value pair if it doesn't exist, or replace an existing name-value pair if it has certain expected attribute values).

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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_StrVal
string ls_AttributesLastPostedByS
string ls_AttributesForumNameS
string ls_AttributesLastPostDateTimeS
string ls_AttributesSubjectS
string ls_AttributesViewsN
string ls_AttributesMessageS
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.UpdateItem" \
//   -d '{
//     "TableName": "Thread",
//     "Key": {
//         "ForumName": {
//             "S": "Amazon DynamoDB"
//         },
//         "Subject": {
//             "S": "Maximum number of items?"
//         }
//     },
//     "UpdateExpression": "set LastPostedBy = :val1",
//     "ConditionExpression": "LastPostedBy = :val2",
//     "ExpressionAttributeValues": {
//         ":val1": {"S": "alice@example.com"},
//         ":val2": {"S": "fred@example.com"}
//     },
//     "ReturnValues": "ALL_NEW"
// }'

// 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": "Thread",
//   "Key": {
//     "ForumName": {
//       "S": "Amazon DynamoDB"
//     },
//     "Subject": {
//       "S": "Maximum number of items?"
//     }
//   },
//   "UpdateExpression": "set LastPostedBy = :val1",
//   "ConditionExpression": "LastPostedBy = :val2",
//   "ExpressionAttributeValues": {
//     ":val1": {
//       "S": "alice@example.com"
//     },
//     ":val2": {
//       "S": "fred@example.com"
//     }
//   },
//   "ReturnValues": "ALL_NEW"
// }

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

loo_Json.UpdateString("TableName","Thread")
loo_Json.UpdateString("Key.ForumName.S","Amazon DynamoDB")
loo_Json.UpdateString("Key.Subject.S","Maximum number of items?")
loo_Json.UpdateString("UpdateExpression","set LastPostedBy = :val1")
loo_Json.UpdateString("ConditionExpression","LastPostedBy = :val2")
loo_Json.UpdateString("ExpressionAttributeValues.:val1.S","alice@example.com")
loo_Json.UpdateString("ExpressionAttributeValues.:val2.S","fred@example.com")
loo_Json.UpdateString("ReturnValues","ALL_NEW")

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

// {
//   "Attributes": {
//     "LastPostedBy": {
//       "S": "alice@example.com"
//     },
//     "ForumName": {
//       "S": "Amazon DynamoDB"
//     },
//     "LastPostDateTime": {
//       "S": "20130320010350"
//     },
//     "Tags": {
//       "SS": [
//         "Update",
//         "Multiple Items",
//         "HelpMe"
//       ]
//     },
//     "Subject": {
//       "S": "Maximum number of items?"
//     },
//     "Views": {
//       "N": "5"
//     },
//     "Message": {
//       "S": "I want to put 10 million data items to an Amazon DynamoDB table.  Is there an upper limit?"
//     }
//   }
// }

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

ls_AttributesLastPostedByS = loo_JsonResponse.StringOf("Attributes.LastPostedBy.S")
ls_AttributesForumNameS = loo_JsonResponse.StringOf("Attributes.ForumName.S")
ls_AttributesLastPostDateTimeS = loo_JsonResponse.StringOf("Attributes.LastPostDateTime.S")
ls_AttributesSubjectS = loo_JsonResponse.StringOf("Attributes.Subject.S")
ls_AttributesViewsN = loo_JsonResponse.StringOf("Attributes.Views.N")
ls_AttributesMessageS = loo_JsonResponse.StringOf("Attributes.Message.S")
i = 0
li_Count_i = loo_JsonResponse.SizeOfArray("Attributes.Tags.SS")
do while i < li_Count_i
    loo_JsonResponse.I = i
    ls_StrVal = loo_JsonResponse.StringOf("Attributes.Tags.SS[i]")
    i = i + 1
loop


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