81 lines
2 KiB
Markdown
81 lines
2 KiB
Markdown
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---
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id: 8b6h
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tags: [AWS, databases, dynamodb]
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created: Sunday, June 23, 2024
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---
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# DynamoDB SDK commands
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The following commands are for using `@aws-sdk/client-dynamodb` (the JS SDK).
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## Create client
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```js
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import DynamoDBClient from "@aws-sdk/client-dynamodb";
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const client = new DynamoDBClient({
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region: "eu-west-2",
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accessKeyId: process.env.ACCESS_KEY_ID,
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secretAccessKey: process.env.ACCESS_KEY_ID,
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});
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```
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### DynamoDB Document Client
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The Document Client returns the data as a standard JSON document in the manner
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of a document-based NoSQL database. Without it, DynamoDB will return the data
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with type data which is unwieldy and hard to parse.
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To transform into a document structure:
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```js
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import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
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import { DynamoDBDocumentClient } from "@aws-sdk/lib-dynamodb";
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const client = new DynamoDBClient({
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region: "eu-west-2",
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accessKeyId: process.env.ACCESS_KEY_ID,
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secretAccessKey: process.env.ACCESS_KEY_ID,
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});
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const dynamoDbDocumentClient = DynamoDBDocumentClient.from(client);
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```
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## Query a table
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Querying is the most performant and cost-effective method since it is an O(1)
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lookup against a partition key or secondary index.
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```js
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import { DynamoDBDocumentClient, QueryCommand } from "@aws-sdk/lib-dynamodb";
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const params = {
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TableName: "YourTableName",
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KeyConditionExpression: "#pk = :pk",
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ExpressionAttributeNames: { "#pk": "PrimaryKeyAttributeName" },
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ExpressionAttributeValues: { ":pk": "PrimaryKeyValue" },
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};
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const dynamoDbDocumentClient = DynamoDBDocumentClient.from(client);
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const data = await dynamoDbDocumentClient.send(new QueryCommand(params));
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console.log(data);
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```
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## Scan a table
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Scanning is less performant (O(n)) and most expensive since it requires checking
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every item in the database.
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```js
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import { DynamoDBDocumentClient, ScanCommand } from "@aws-sdk/lib-dynamodb";
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const params = {
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TableName: "YourTableName",
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};
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const dynamoDbDocumentClient = DynamoDBDocumentClient.from(client);
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const data = await dynamoDbDocumentClient.send(new ScanCommand(params));
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```
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## Related notes
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