Visual FoxPro

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. Visual FoxPro

LOCAL lnSuccess
LOCAL loRest
LOCAL loAuthAws
LOCAL lnBTls
LOCAL lnPort
LOCAL lnBAutoReconnect
LOCAL loJson
LOCAL loSbRequestBody
LOCAL loSbResponseBody
LOCAL lnRespStatusCode
LOCAL loJsonResponse
LOCAL lcStrVal
LOCAL lcAttributesLastPostedByS
LOCAL lcAttributesForumNameS
LOCAL lcAttributesLastPostDateTimeS
LOCAL lcAttributesSubjectS
LOCAL lcAttributesMessageS
LOCAL i
LOCAL lnCount_i

lnSuccess = 0

loRest = CreateObject('Chilkat.Rest')

* 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('Chilkat.AuthAws')
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/
lnBTls = 1
lnPort = 443
lnBAutoReconnect = 1
lnSuccess = loRest.Connect("dynamodb.us-west-2.amazonaws.com",lnPort,lnBTls,lnBAutoReconnect)
IF (lnSuccess <> 1) THEN
    ? "ConnectFailReason: " + STR(loRest.ConnectFailReason)
    ? loRest.LastErrorText
    RELEASE loRest
    RELEASE loAuthAws
    CANCEL
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('Chilkat.JsonObject')
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('Chilkat.StringBuilder')
loJson.EmitSb(loSbRequestBody)
loSbResponseBody = CreateObject('Chilkat.StringBuilder')
lnSuccess = loRest.FullRequestSb("POST","/",loSbRequestBody,loSbResponseBody)
IF (lnSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    RELEASE loAuthAws
    RELEASE loJson
    RELEASE loSbRequestBody
    RELEASE loSbResponseBody
    CANCEL
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
    CANCEL
ENDIF

loJsonResponse = CreateObject('Chilkat.JsonObject')
loJsonResponse.LoadSb(loSbResponseBody)

loJsonResponse.EmitCompact = 0
? 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