From d569b02ef8248c7b3805b116b7307189ab6b1ac5 Mon Sep 17 00:00:00 2001
From: Truong Ma Phi <trmaphi@gmail.com>
Date: Wed, 23 Sep 2020 23:35:55 +0700
Subject: [PATCH] feat: how to implement auto increment counter in DynamoDB

---
 .../incremental-counter.json                  | 19 +++++++++
 dynamodb-incremental-counter/readme.md        | 39 +++++++++++++++++++
 .../update-and-get-current-value-counter.json | 15 +++++++
 3 files changed, 73 insertions(+)
 create mode 100644 dynamodb-incremental-counter/incremental-counter.json
 create mode 100644 dynamodb-incremental-counter/readme.md
 create mode 100644 dynamodb-incremental-counter/update-and-get-current-value-counter.json

diff --git a/dynamodb-incremental-counter/incremental-counter.json b/dynamodb-incremental-counter/incremental-counter.json
new file mode 100644
index 0000000..4ea0be1
--- /dev/null
+++ b/dynamodb-incremental-counter/incremental-counter.json
@@ -0,0 +1,19 @@
+{
+    "TableName": "Counter",
+    "KeySchema": [
+        {
+            "AttributeName": "CounterEntity",
+            "KeyType": "HASH"
+        }
+    ],
+    "AttributeDefinitions": [
+        {
+            "AttributeName": "CounterEntity",
+            "AttributeType": "S"
+        }
+    ],
+    "ProvisionedThroughput": {
+        "ReadCapacityUnits": 1,
+        "WriteCapacityUnits": 1
+    }
+}
diff --git a/dynamodb-incremental-counter/readme.md b/dynamodb-incremental-counter/readme.md
new file mode 100644
index 0000000..19ea122
--- /dev/null
+++ b/dynamodb-incremental-counter/readme.md
@@ -0,0 +1,39 @@
+# DynamoDB cloud native incremental counter
+----------
+
+## Create table for counter
+
+```bash
+aws dynamodb create-table --cli-input-json file://dynamodb-incremental-counter/incremental-counter.json --endpoint-url http://localhost:8000
+{
+    "Attributes": {
+        "CreationDateTime": "2020-09-23T23:35:02.649000+07:00",
+        "ProvisionedThroughput": {
+            "LastIncreaseDateTime": "1970-01-01T07:00:00+07:00",
+            "LastDecreaseDateTime": "1970-01-01T07:00:00+07:00",
+            "NumberOfDecreasesToday": 0,
+            "ReadCapacityUnits": 1,
+            "WriteCapacityUnits": 1
+        },
+        "TableSizeBytes": 0,
+        "ItemCount": 0,
+        "TableArn": "arn:aws:dynamodb:ddblocal:000000000000:table/Counter"
+    }
+}
+```
+
+## Update and get the last counter item value
+
+```bash
+aws dynamodb update-item --cli-input-json file://dynamodb-incremental-counter/update-and-get-current-value-counter.json --endpoint-url http://localhost:8000
+{
+    "Attributes": {
+        "CounterEntity": {
+            "S": "Entity"
+        },
+        "currentValue": {
+            "N": "1"
+        }
+    }
+}
+```
diff --git a/dynamodb-incremental-counter/update-and-get-current-value-counter.json b/dynamodb-incremental-counter/update-and-get-current-value-counter.json
new file mode 100644
index 0000000..d229245
--- /dev/null
+++ b/dynamodb-incremental-counter/update-and-get-current-value-counter.json
@@ -0,0 +1,15 @@
+{
+    "TableName": "Counter",
+    "Key": {
+        "CounterEntity": {
+            "S": "Entity"
+        }
+    },
+    "UpdateExpression": "ADD currentValue :count",
+    "ExpressionAttributeValues": { 
+        ":count": {
+            "N": "1"
+        }
+    },
+    "ReturnValues": "ALL_NEW"
+}