feat: how to implement auto increment counter in DynamoDB

trmaphi · Sep 23, 2020 · d569b02 · d569b02
1 parent a8c6a8a
commit d569b02
Show file tree

Hide file tree

Showing 3 changed files with 73 additions and 0 deletions.
diff --git a/dynamodb-incremental-counter/incremental-counter.json 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
@@ -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
@@ -0,0 +1,15 @@
+{
+    "TableName": "Counter",
+    "Key": {
+        "CounterEntity": {
+            "S": "Entity"
+        }
+    },
+    "UpdateExpression": "ADD currentValue :count",
+    "ExpressionAttributeValues": { 
+        ":count": {
+            "N": "1"
+        }
+    },
+    "ReturnValues": "ALL_NEW"
+}