AWS code-library documentation change
Summary
Added warm throughput table creation example
Security assessment
Documents capacity provisioning features without security implications.
Diff
diff --git a/code-library/latest/ug/javascript_3_dynamodb_code_examples.md b/code-library/latest/ug/javascript_3_dynamodb_code_examples.md index 9ba23d1b4..9f05bcf54 100644 --- a//code-library/latest/ug/javascript_3_dynamodb_code_examples.md +++ b//code-library/latest/ug/javascript_3_dynamodb_code_examples.md @@ -1305,0 +1306,337 @@ This example is also available in the [AWS SDK for JavaScript v3 developer guide +The following code example shows how to compare multiple values with a single attribute in DynamoDB. + + * Use the IN operator to compare multiple values with a single attribute. + + * Compare the IN operator with multiple OR conditions. + + * Understand the performance and expression complexity benefits of using IN. + + + + +**SDK for JavaScript (v3)** + + +Compare multiple values with a single attribute using AWS SDK for JavaScript. + + + const { DynamoDBClient } = require("@aws-sdk/client-dynamodb"); + const { + DynamoDBDocumentClient, + ScanCommand, + QueryCommand + } = require("@aws-sdk/lib-dynamodb"); + + /** + * Query or scan a DynamoDB table to find items where an attribute matches any value from a list. + * + * This function demonstrates the use of the IN operator to compare a single attribute + * against multiple possible values, which is more efficient than using multiple OR conditions. + * + * @param {Object} config - AWS configuration object + * @param {string} tableName - The name of the DynamoDB table + * @param {string} attributeName - The name of the attribute to compare against the values list + * @param {Array} valuesList - List of values to compare the attribute against + * @param {string} [partitionKeyName] - Optional name of the partition key attribute for query operations + * @param {string} [partitionKeyValue] - Optional value of the partition key to query + * @returns {Promise<Object>} - The response from DynamoDB containing the matching items + */ + async function compareMultipleValues( + config, + tableName, + attributeName, + valuesList, + partitionKeyName, + partitionKeyValue + ) { + // Initialize the DynamoDB client + const client = new DynamoDBClient(config); + const docClient = DynamoDBDocumentClient.from(client); + + // Create the filter expression using the IN operator + const filterExpression = `${attributeName} IN (${valuesList.map((_, index) => `:val${index}`).join(', ')})`; + + // Create expression attribute values for the values list + const expressionAttributeValues = valuesList.reduce((acc, val, index) => { + acc[`:val${index}`] = val; + return acc; + }, {}); + + // If partition key is provided, perform a query operation + if (partitionKeyName && partitionKeyValue) { + const keyCondition = `${partitionKeyName} = :partitionKey`; + expressionAttributeValues[':partitionKey'] = partitionKeyValue; + + // Initialize array to collect all items + let allItems = []; + let lastEvaluatedKey; + + // Use pagination to get all results + do { + const params = { + TableName: tableName, + KeyConditionExpression: keyCondition, + FilterExpression: filterExpression, + ExpressionAttributeValues: expressionAttributeValues + }; + + // Add ExclusiveStartKey if we have a lastEvaluatedKey from a previous query + if (lastEvaluatedKey) { + params.ExclusiveStartKey = lastEvaluatedKey; + } + + const response = await docClient.send(new QueryCommand(params)); + + // Add the items from this page to our collection + if (response.Items && response.Items.length > 0) { + allItems = [...allItems, ...response.Items]; + } + + // Get the key for the next page of results + lastEvaluatedKey = response.LastEvaluatedKey; + } while (lastEvaluatedKey); + + // Return the complete result + return { + Items: allItems, + Count: allItems.length + }; + } else { + // Otherwise, perform a scan operation + // Initialize array to collect all items + let allItems = []; + let lastEvaluatedKey; + + // Use pagination to get all results + do { + const params = { + TableName: tableName, + FilterExpression: filterExpression, + ExpressionAttributeValues: expressionAttributeValues + }; + + // Add ExclusiveStartKey if we have a lastEvaluatedKey from a previous scan + if (lastEvaluatedKey) { + params.ExclusiveStartKey = lastEvaluatedKey; + } + + const response = await docClient.send(new ScanCommand(params)); + + // Add the items from this page to our collection + if (response.Items && response.Items.length > 0) { + allItems = [...allItems, ...response.Items]; + } + + // Get the key for the next page of results + lastEvaluatedKey = response.LastEvaluatedKey; + } while (lastEvaluatedKey); + + // Return the complete result + return { + Items: allItems, + Count: allItems.length + }; + } + } + + /** + * Alternative implementation using multiple OR conditions instead of the IN operator. + * + * This function is provided for comparison to show why using the IN operator is preferable. + * With many values, this approach becomes verbose and less efficient. + * + * @param {Object} config - AWS configuration object + * @param {string} tableName - The name of the DynamoDB table + * @param {string} attributeName - The name of the attribute to compare against the values list + * @param {Array} valuesList - List of values to compare the attribute against + * @param {string} [partitionKeyName] - Optional name of the partition key attribute for query operations + * @param {string} [partitionKeyValue] - Optional value of the partition key to query + * @returns {Promise<Object>} - The response from DynamoDB containing the matching items + */ + async function compareWithOrConditions( + config, + tableName, + attributeName, + valuesList, + partitionKeyName, + partitionKeyValue + ) { + // Initialize the DynamoDB client + const client = new DynamoDBClient(config); + const docClient = DynamoDBDocumentClient.from(client); + + // If no values provided, return empty result + if (!valuesList || valuesList.length === 0) { + return { + Items: [], + Count: 0 + }; + } + + // Create the filter expression using multiple OR conditions + const filterConditions = valuesList.map((_, index) => `${attributeName} = :val${index}`); + const filterExpression = filterConditions.join(' OR '); + + // Create expression attribute values for the values list + const expressionAttributeValues = valuesList.reduce((acc, val, index) => { + acc[`:val${index}`] = val; + return acc; + }, {}); + + // If partition key is provided, perform a query operation + if (partitionKeyName && partitionKeyValue) { + const keyCondition = `${partitionKeyName} = :partitionKey`; + expressionAttributeValues[':partitionKey'] = partitionKeyValue; + + // Initialize array to collect all items + let allItems = []; + let lastEvaluatedKey; + + // Use pagination to get all results + do { + const params = { + TableName: tableName, + KeyConditionExpression: keyCondition, + FilterExpression: filterExpression,