Lianja

DynamoDB - DeleteItem

See more Amazon DynamoDB Examples

Deletes a single item in a table by primary key. You can perform a conditional delete operation that deletes the item if it exists, or if it has an expected attribute value. Lianja

llSuccess = .F.

loRest = createobject("CkRest")

// 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.DeleteItem" \
//   -d '{
//     "TableName": "Thread",
//     "Key": {
//         "ForumName": {
//             "S": "Amazon DynamoDB"
//         },
//         "Subject": {
//             "S": "How do I update multiple items?"
//         }
//     },
//     "ConditionExpression": "attribute_not_exists(Replies)",
//     "ReturnValues": "ALL_OLD"
// }'

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

loAuthAws = createobject("CkAuthAws")
loAuthAws.AccessKey = "AWS_ACCESS_KEY"
loAuthAws.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.)
loAuthAws.Region = "us-west-2"
loAuthAws.ServiceName = "dynamodb"
// SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
loRest.SetAuthAws(loAuthAws)

// URL: https://dynamodb.us-west-2.amazonaws.com/
llBTls = .T.
lnPort = 443
llBAutoReconnect = .T.
llSuccess = loRest.Connect("dynamodb.us-west-2.amazonaws.com",lnPort,llBTls,llBAutoReconnect)
if (llSuccess <> .T.) then
    ? "ConnectFailReason: " + str(loRest.ConnectFailReason)
    ? loRest.LastErrorText
    release loRest
    release loAuthAws
    return
endif

// 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": "How do I update multiple items?"
//     }
//   },
//   "ConditionExpression": "attribute_not_exists(Replies)",
//   "ReturnValues": "ALL_OLD"
// }

loJson = createobject("CkJsonObject")
loJson.UpdateString("TableName","Thread")
loJson.UpdateString("Key.ForumName.S","Amazon DynamoDB")
loJson.UpdateString("Key.Subject.S","How do I update multiple items?")
loJson.UpdateString("ConditionExpression","attribute_not_exists(Replies)")
loJson.UpdateString("ReturnValues","ALL_OLD")

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

loSbRequestBody = createobject("CkStringBuilder")
loJson.EmitSb(loSbRequestBody)
loSbResponseBody = createobject("CkStringBuilder")
llSuccess = loRest.FullRequestSb("POST","/",loSbRequestBody,loSbResponseBody)
if (llSuccess <> .T.) then
    ? loRest.LastErrorText
    release loRest
    release loAuthAws
    release loJson
    release loSbRequestBody
    release loSbResponseBody
    return
endif

lnRespStatusCode = loRest.ResponseStatusCode
? "response status code = " + str(lnRespStatusCode)
if (lnRespStatusCode >= 400) then
    ? "Response Status Code = " + str(lnRespStatusCode)
    ? "Response Header:"
    ? loRest.ResponseHeader
    ? "Response Body:"
    ? loSbResponseBody.GetAsString()
    release loRest
    release loAuthAws
    release loJson
    release loSbRequestBody
    release loSbResponseBody
    return
endif

loJsonResponse = createobject("CkJsonObject")
loJsonResponse.LoadSb(loSbResponseBody)

loJsonResponse.EmitCompact = .F.
? loJsonResponse.Emit()

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

// {
//   "Attributes": {
//     "LastPostedBy": {
//       "S": "fred@example.com"
//     },
//     "ForumName": {
//       "S": "Amazon DynamoDB"
//     },
//     "LastPostDateTime": {
//       "S": "201303201023"
//     },
//     "Tags": {
//       "SS": [
//         "Update",
//         "Multiple Items",
//         "HelpMe"
//       ]
//     },
//     "Subject": {
//       "S": "How do I update multiple items?"
//     },
//     "Message": {
//       "S": "I want to update multiple items in a single call. What's the best way to do that?"
//     }
//   }
// }

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

lcAttributesLastPostedByS = loJsonResponse.StringOf("Attributes.LastPostedBy.S")
lcAttributesForumNameS = loJsonResponse.StringOf("Attributes.ForumName.S")
lcAttributesLastPostDateTimeS = loJsonResponse.StringOf("Attributes.LastPostDateTime.S")
lcAttributesSubjectS = loJsonResponse.StringOf("Attributes.Subject.S")
lcAttributesMessageS = loJsonResponse.StringOf("Attributes.Message.S")
i = 0
lnCount_i = loJsonResponse.SizeOfArray("Attributes.Tags.SS")
do while i < lnCount_i
    loJsonResponse.I = i
    lcStrVal = loJsonResponse.StringOf("Attributes.Tags.SS[i]")
    i = i + 1
enddo


release loRest
release loAuthAws
release loJson
release loSbRequestBody
release loSbResponseBody
release loJsonResponse