# Count expression operators in DynamoDB with an AWS SDK
<a name="example_dynamodb_Scenario_ExpressionOperatorCounting_section"></a>

The following code examples show how to count expression operators in DynamoDB.
+ Understand DynamoDB's 300 operator limit.
+ Count operators in complex expressions.
+ Optimize expressions to stay within limits.

------
#### [ Java ]

**SDK for Java 2.x**  
Demonstrate expression operator counting using AWS SDK for Java 2.x.  

```
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.AttributeValue;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
import software.amazon.awssdk.services.dynamodb.model.UpdateItemRequest;
import software.amazon.awssdk.services.dynamodb.model.UpdateItemResponse;

import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

    /**
     * Creates a complex filter expression with a specified number of conditions.
     *
     * <p>This method demonstrates how to generate a complex expression with
     * a specific number of operators to test the 300 operator limit.
     *
     * @param conditionsCount Number of conditions to include
     * @param useAnd Whether to use AND (true) or OR (false) between conditions
     * @return Map containing the filter expression, attribute values, and operator count
     */
    public static Map<String, Object> createComplexFilterExpression(int conditionsCount, boolean useAnd) {
        // Initialize the expression parts and attribute values
        StringBuilder filterExpression = new StringBuilder();
        Map<String, AttributeValue> expressionAttributeValues = new HashMap<>();

        // Generate the specified number of conditions
        for (int i = 0; i < conditionsCount; i++) {
            // Add the operator between conditions (except for the first one)
            if (i > 0) {
                filterExpression.append(useAnd ? " AND " : " OR ");
            }

            // Alternate between different comparison operators for variety
            String valueKey = ":val" + i;

            switch (i % 5) {
                case 0:
                    filterExpression.append("attribute").append(i).append(" = ").append(valueKey);
                    expressionAttributeValues.put(
                        valueKey, AttributeValue.builder().s("value" + i).build());
                    break;
                case 1:
                    filterExpression.append("attribute").append(i).append(" > ").append(valueKey);
                    expressionAttributeValues.put(
                        valueKey, AttributeValue.builder().n(String.valueOf(i)).build());
                    break;
                case 2:
                    filterExpression.append("attribute").append(i).append(" < ").append(valueKey);
                    expressionAttributeValues.put(
                        valueKey,
                        AttributeValue.builder().n(String.valueOf(i * 10)).build());
                    break;
                case 3:
                    filterExpression
                        .append("contains(attribute")
                        .append(i)
                        .append(", ")
                        .append(valueKey)
                        .append(")");
                    expressionAttributeValues.put(
                        valueKey, AttributeValue.builder().s("substring" + i).build());
                    break;
                case 4:
                    filterExpression
                        .append("attribute_exists(attribute")
                        .append(i)
                        .append(")");
                    break;
                default:
                    // This case will never be reached, but added to satisfy checkstyle
                    break;
            }
        }

        // Calculate the operator count
        // Each condition has 1 operator (=, >, <, contains, attribute_exists)
        // Each AND or OR between conditions is 1 operator
        int operatorCount = conditionsCount + (conditionsCount > 0 ? conditionsCount - 1 : 0);

        // Create the result map
        Map<String, Object> result = new HashMap<>();
        result.put("filterExpression", filterExpression.toString());
        result.put("expressionAttributeValues", expressionAttributeValues);
        result.put("operatorCount", operatorCount);

        return result;
    }

    /**
     * Creates a complex update expression with a specified number of operations.
     *
     * <p>This method demonstrates how to generate a complex update expression with
     * a specific number of operators to test the 300 operator limit.
     *
     * @param operationsCount Number of operations to include
     * @return Map containing the update expression, attribute values, and operator count
     */
    public static Map<String, Object> createComplexUpdateExpression(int operationsCount) {
        // Initialize the expression parts and attribute values
        StringBuilder updateExpression = new StringBuilder("SET ");
        Map<String, AttributeValue> expressionAttributeValues = new HashMap<>();

        // Generate the specified number of SET operations
        for (int i = 0; i < operationsCount; i++) {
            // Add comma between operations (except for the first one)
            if (i > 0) {
                updateExpression.append(", ");
            }

            // Alternate between different types of SET operations
            String valueKey = ":val" + i;

            switch (i % 3) {
                case 0:
                    // Simple assignment (1 operator: =)
                    updateExpression.append("attribute").append(i).append(" = ").append(valueKey);
                    expressionAttributeValues.put(
                        valueKey, AttributeValue.builder().s("value" + i).build());
                    break;
                case 1:
                    // Addition (2 operators: = and +)
                    updateExpression
                        .append("attribute")
                        .append(i)
                        .append(" = attribute")
                        .append(i)
                        .append(" + ")
                        .append(valueKey);
                    expressionAttributeValues.put(
                        valueKey, AttributeValue.builder().n(String.valueOf(i)).build());
                    break;
                case 2:
                    // Conditional assignment with if_not_exists (2 operators: = and if_not_exists)
                    updateExpression
                        .append("attribute")
                        .append(i)
                        .append(" = if_not_exists(attribute")
                        .append(i)
                        .append(", ")
                        .append(valueKey)
                        .append(")");
                    expressionAttributeValues.put(
                        valueKey,
                        AttributeValue.builder().n(String.valueOf(i * 10)).build());
                    break;
                default:
                    // This case will never be reached, but added to satisfy checkstyle
                    break;
            }
        }

        // Calculate the operator count
        // Each operation has 1-2 operators as noted above
        int operatorCount = 0;
        for (int i = 0; i < operationsCount; i++) {
            operatorCount += (i % 3 == 0) ? 1 : 2;
        }

        // Create the result map
        Map<String, Object> result = new HashMap<>();
        result.put("updateExpression", updateExpression.toString());
        result.put("expressionAttributeValues", expressionAttributeValues);
        result.put("operatorCount", operatorCount);

        return result;
    }

    /**
     * Test the operator limit by attempting an operation with a complex expression.
     *
     * <p>This method demonstrates what happens when an expression approaches or
     * exceeds the 300 operator limit.
     *
     * @param dynamoDbClient The DynamoDB client
     * @param tableName The name of the DynamoDB table
     * @param key The key of the item to update
     * @param operatorCount Target number of operators to include
     * @return Map containing the result of the operation attempt
     */
    public static Map<String, Object> testOperatorLimit(
        DynamoDbClient dynamoDbClient, String tableName, Map<String, AttributeValue> key, int operatorCount) {

        // Create a complex update expression with the specified operator count
        Map<String, Object> expressionData =
            createComplexUpdateExpression((int) Math.ceil(operatorCount / 1.5)); // Adjust to get close to target count

        String updateExpression = (String) expressionData.get("updateExpression");
        @SuppressWarnings("unchecked")
        Map<String, AttributeValue> expressionAttributeValues =
            (Map<String, AttributeValue>) expressionData.get("expressionAttributeValues");
        int actualCount = (int) expressionData.get("operatorCount");

        System.out.println("Generated update expression with approximately " + actualCount + " operators");

        // Define the update parameters
        UpdateItemRequest request = UpdateItemRequest.builder()
            .tableName(tableName)
            .key(key)
            .updateExpression(updateExpression)
            .expressionAttributeValues(expressionAttributeValues)
            .returnValues("UPDATED_NEW")
            .build();

        try {
            // Attempt the update operation
            UpdateItemResponse response = dynamoDbClient.updateItem(request);

            Map<String, Object> result = new HashMap<>();
            result.put("success", true);
            result.put("message", "Operation succeeded with " + actualCount + " operators");
            result.put("data", response);
            return result;

        } catch (DynamoDbException e) {
            // Check if the error is due to exceeding the operator limit
            if (e.getMessage().contains("too many operators")) {
                Map<String, Object> result = new HashMap<>();
                result.put("success", false);
                result.put("message", "Operation failed: " + e.getMessage());
                result.put("operatorCount", actualCount);
                return result;
            }

            // Return other errors
            Map<String, Object> result = new HashMap<>();
            result.put("success", false);
            result.put("message", "Operation failed: " + e.getMessage());
            result.put("error", e);
            return result;
        }
    }

    /**
     * Break down a complex expression into multiple simpler operations.
     *
     * <p>This method demonstrates how to handle expressions that would exceed
     * the 300 operator limit by breaking them into multiple operations.
     *
     * @param dynamoDbClient The DynamoDB client
     * @param tableName The name of the DynamoDB table
     * @param key The key of the item to update
     * @param totalOperations Total number of operations to perform
     * @return Map containing the results of the operations
     */
    public static Map<String, Object> breakDownComplexExpression(
        DynamoDbClient dynamoDbClient, String tableName, Map<String, AttributeValue> key, int totalOperations) {

        // Calculate how many operations we can safely include in each batch
        // Using 150 as a conservative limit (well below 300)
        final int operationsPerBatch = 100;
        final int batchCount = (int) Math.ceil((double) totalOperations / operationsPerBatch);

        System.out.println("Breaking down " + totalOperations + " operations into " + batchCount + " batches");

        Map<String, Object> results = new HashMap<>();
        results.put("totalBatches", batchCount);

        Map<Integer, Map<String, Object>> batchResults = new HashMap<>();

        // Process each batch
        for (int batch = 0; batch < batchCount; batch++) {
            // Calculate the operations for this batch
            int batchStart = batch * operationsPerBatch;
            int batchEnd = Math.min(batchStart + operationsPerBatch, totalOperations);
            int batchSize = batchEnd - batchStart;

            System.out.println(
                "Processing batch " + (batch + 1) + "/" + batchCount + " with " + batchSize + " operations");

            // Create an update expression for this batch
            Map<String, Object> expressionData = createComplexUpdateExpression(batchSize);

            String updateExpression = (String) expressionData.get("updateExpression");
            @SuppressWarnings("unchecked")
            Map<String, AttributeValue> expressionAttributeValues =
                (Map<String, AttributeValue>) expressionData.get("expressionAttributeValues");
            int operatorCount = (int) expressionData.get("operatorCount");

            // Define the update parameters
            UpdateItemRequest request = UpdateItemRequest.builder()
                .tableName(tableName)
                .key(key)
                .updateExpression(updateExpression)
                .expressionAttributeValues(expressionAttributeValues)
                .returnValues("UPDATED_NEW")
                .build();

            try {
                // Perform the update operation for this batch
                UpdateItemResponse response = dynamoDbClient.updateItem(request);

                Map<String, Object> batchResult = new HashMap<>();
                batchResult.put("batch", batch + 1);
                batchResult.put("success", true);
                batchResult.put("operatorCount", operatorCount);
                batchResult.put("attributes", response.attributes());

                batchResults.put(batch, batchResult);

            } catch (DynamoDbException e) {
                Map<String, Object> batchResult = new HashMap<>();
                batchResult.put("batch", batch + 1);
                batchResult.put("success", false);
                batchResult.put("operatorCount", operatorCount);
                batchResult.put("error", e.getMessage());

                batchResults.put(batch, batchResult);

                // Continue with next batch instead of breaking
                continue;
            }
        }

        results.put("results", batchResults);
        return results;
    }

    /**
     * Count operators in a DynamoDB expression based on the rules in the documentation.
     *
     * <p>This method demonstrates how operators are counted according to the
     * DynamoDB documentation.
     *
     * @param expression The DynamoDB expression to analyze
     * @return Map containing the breakdown of operator counts
     */
    public static Map<String, Integer> countOperatorsInExpression(String expression) {
        // Initialize counters for different operator types
        Map<String, Integer> counts = new HashMap<>();
        counts.put("comparisonOperators", 0);
        counts.put("logicalOperators", 0);
        counts.put("functions", 0);
        counts.put("arithmeticOperators", 0);
        counts.put("specialOperators", 0);
        counts.put("total", 0);

        // Count comparison operators (=, <>, <, <=, >, >=)
        // This is a simplified approach and may not catch all cases
        int comparisonCount = 0;
        Pattern comparisonPattern = Pattern.compile("(=|<>|<=|>=|<|>)");
        Matcher comparisonMatcher = comparisonPattern.matcher(expression);
        while (comparisonMatcher.find()) {
            comparisonCount++;
        }
        counts.put("comparisonOperators", comparisonCount);

        // Count logical operators (AND, OR, NOT)
        int andCount = countOccurrences(expression, "\\bAND\\b");
        int orCount = countOccurrences(expression, "\\bOR\\b");
        int notCount = countOccurrences(expression, "\\bNOT\\b");
        counts.put("logicalOperators", andCount + orCount + notCount);

        // Count functions (attribute_exists, attribute_not_exists, attribute_type, begins_with, contains, size)
        int functionCount = countOccurrences(
            expression,
            "\\b(attribute_exists|attribute_not_exists|attribute_type|begins_with|contains|size|if_not_exists)\\(");
        counts.put("functions", functionCount);

        // Count arithmetic operators (+ and -)
        // This is a simplified approach and may not catch all cases
        int arithmeticCount = 0;
        Pattern arithmeticPattern = Pattern.compile("[a-zA-Z0-9_)\\]]\\s*[\\+\\-]\\s*[a-zA-Z0-9_:(]");
        Matcher arithmeticMatcher = arithmeticPattern.matcher(expression);
        while (arithmeticMatcher.find()) {
            arithmeticCount++;
        }
        counts.put("arithmeticOperators", arithmeticCount);

        // Count special operators (BETWEEN, IN)
        int betweenCount = countOccurrences(expression, "\\bBETWEEN\\b");
        int inCount = countOccurrences(expression, "\\bIN\\b");
        counts.put("specialOperators", betweenCount + inCount);

        // Add extra operators for BETWEEN (each BETWEEN includes an AND)
        int currentLogicalOps = counts.getOrDefault("logicalOperators", 0);
        counts.put("logicalOperators", currentLogicalOps + betweenCount);

        // Calculate total
        int total = counts.getOrDefault("comparisonOperators", 0)
            + counts.getOrDefault("logicalOperators", 0)
            + counts.getOrDefault("functions", 0)
            + counts.getOrDefault("arithmeticOperators", 0)
            + counts.getOrDefault("specialOperators", 0);
        counts.put("total", total);

        return counts;
    }

    /**
     * Helper method to count occurrences of a pattern in a string.
     *
     * @param text The text to search in
     * @param regex The regular expression pattern to search for
     * @return The number of occurrences
     */
    private static int countOccurrences(String text, String regex) {
        final Pattern pattern = Pattern.compile(regex);
        final Matcher matcher = pattern.matcher(text);
        int count = 0;
        while (matcher.find()) {
            count++;
        }
        return count;
    }
```
Example usage of expression operator counting with AWS SDK for Java 2.x.  

```
    public static void exampleUsage(DynamoDbClient dynamoDbClient, String tableName) {
        // Example key
        Map<String, AttributeValue> key = new HashMap<>();
        key.put("ProductId", AttributeValue.builder().s("P12345").build());

        System.out.println("Demonstrating DynamoDB expression operator counting and the 300 operator limit");

        try {
            // Example 1: Analyze a simple expression
            System.out.println("\nExample 1: Analyzing a simple expression");
            String simpleExpression = "Price = :price AND Rating > :rating AND Category IN (:cat1, :cat2, :cat3)";
            Map<String, Integer> simpleCount = countOperatorsInExpression(simpleExpression);

            System.out.println("Expression: " + simpleExpression);
            System.out.println("Operator count breakdown:");
            System.out.println("- Comparison operators: " + simpleCount.get("comparisonOperators"));
            System.out.println("- Logical operators: " + simpleCount.get("logicalOperators"));
            System.out.println("- Functions: " + simpleCount.get("functions"));
            System.out.println("- Arithmetic operators: " + simpleCount.get("arithmeticOperators"));
            System.out.println("- Special operators: " + simpleCount.get("specialOperators"));
            System.out.println("- Total operators: " + simpleCount.get("total"));

            // Example 2: Analyze a complex expression
            System.out.println("\nExample 2: Analyzing a complex expression");
            String complexExpression = "(attribute_exists(Category) AND Size BETWEEN :min AND :max) OR "
                + "(Price > :price AND contains(Description, :keyword) AND "
                + "(Rating >= :minRating OR Reviews > :minReviews))";
            Map<String, Integer> complexCount = countOperatorsInExpression(complexExpression);

            System.out.println("Expression: " + complexExpression);
            System.out.println("Operator count breakdown:");
            System.out.println("- Comparison operators: " + complexCount.get("comparisonOperators"));
            System.out.println("- Logical operators: " + complexCount.get("logicalOperators"));
            System.out.println("- Functions: " + complexCount.get("functions"));
            System.out.println("- Arithmetic operators: " + complexCount.get("arithmeticOperators"));
            System.out.println("- Special operators: " + complexCount.get("specialOperators"));
            System.out.println("- Total operators: " + complexCount.get("total"));

            // Example 3: Test approaching the operator limit
            System.out.println("\nExample 3: Testing an expression approaching the operator limit");
            Map<String, Object> approachingLimit = testOperatorLimit(dynamoDbClient, tableName, key, 290);
            System.out.println(approachingLimit.get("message"));

            // Example 4: Test exceeding the operator limit
            System.out.println("\nExample 4: Testing an expression exceeding the operator limit");
            Map<String, Object> exceedingLimit = testOperatorLimit(dynamoDbClient, tableName, key, 310);
            System.out.println(exceedingLimit.get("message"));

            // Example 5: Breaking down a complex expression
            System.out.println("\nExample 5: Breaking down a complex expression into multiple operations");
            Map<String, Object> breakdownResult = breakDownComplexExpression(dynamoDbClient, tableName, key, 500);
            @SuppressWarnings("unchecked")
            Map<Integer, Map<String, Object>> results =
                (Map<Integer, Map<String, Object>>) breakdownResult.get("results");
            System.out.println(
                "Processed " + results.size() + " of " + breakdownResult.get("totalBatches") + " batches");

            // Explain the operator counting rules
            System.out.println("\nKey points about DynamoDB expression operator counting:");
            System.out.println("1. The maximum number of operators in any expression is 300");
            System.out.println("2. Each comparison operator (=, <>, <, <=, >, >=) counts as 1 operator");
            System.out.println("3. Each logical operator (AND, OR, NOT) counts as 1 operator");
            System.out.println("4. Each function call (attribute_exists, contains, etc.) counts as 1 operator");
            System.out.println("5. Each arithmetic operator (+ or -) counts as 1 operator");
            System.out.println("6. BETWEEN counts as 2 operators (BETWEEN itself and the AND within it)");
            System.out.println("7. IN counts as 1 operator regardless of the number of values");
            System.out.println("8. Parentheses for grouping and attribute paths don't count as operators");
            System.out.println("9. When you exceed the limit, the error always reports '301 operators'");
            System.out.println("10. For complex operations, break them into multiple smaller operations");

        } catch (Exception e) {
            System.err.println("Error: " + e.getMessage());
            e.printStackTrace();
        }
    }
```
+  For API details, see [UpdateItem](https://docs.aws.amazon.com/goto/SdkForJavaV2/dynamodb-2012-08-10/UpdateItem) in *AWS SDK for Java 2.x API Reference*. 

------
#### [ JavaScript ]

**SDK for JavaScript (v3)**  
Demonstrate expression operator counting using AWS SDK for JavaScript.  

```
const { DynamoDBClient } = require("@aws-sdk/client-dynamodb");
const { 
  DynamoDBDocumentClient, 
  UpdateCommand,
  QueryCommand
} = require("@aws-sdk/lib-dynamodb");

/**
 * Create a complex filter expression with a specified number of conditions.
 * 
 * This function demonstrates how to generate a complex expression with
 * a specific number of operators to test the 300 operator limit.
 * 
 * @param {number} conditionsCount - Number of conditions to include
 * @param {boolean} useAnd - Whether to use AND (true) or OR (false) between conditions
 * @returns {Object} - Object containing the filter expression and attribute values
 */
function createComplexFilterExpression(conditionsCount, useAnd = true) {
  // Initialize the expression parts and attribute values
  const conditions = [];
  const expressionAttributeValues = {};
  
  // Generate the specified number of conditions
  for (let i = 0; i < conditionsCount; i++) {
    // Alternate between different comparison operators for variety
    let condition;
    const valueKey = `:val${i}`;
    
    switch (i % 5) {
      case 0:
        condition = `attribute${i} = ${valueKey}`;
        expressionAttributeValues[valueKey] = `value${i}`;
        break;
      case 1:
        condition = `attribute${i} > ${valueKey}`;
        expressionAttributeValues[valueKey] = i;
        break;
      case 2:
        condition = `attribute${i} < ${valueKey}`;
        expressionAttributeValues[valueKey] = i * 10;
        break;
      case 3:
        condition = `contains(attribute${i}, ${valueKey})`;
        expressionAttributeValues[valueKey] = `substring${i}`;
        break;
      case 4:
        condition = `attribute_exists(attribute${i})`;
        break;
    }
    
    conditions.push(condition);
  }
  
  // Join the conditions with AND or OR
  const operator = useAnd ? " AND " : " OR ";
  const filterExpression = conditions.join(operator);
  
  // Calculate the operator count
  // Each condition has 1 operator (=, >, <, contains, attribute_exists)
  // Each AND or OR between conditions is 1 operator
  const operatorCount = conditionsCount + (conditionsCount > 0 ? conditionsCount - 1 : 0);
  
  return {
    filterExpression,
    expressionAttributeValues,
    operatorCount
  };
}

/**
 * Create a complex update expression with a specified number of operations.
 * 
 * This function demonstrates how to generate a complex update expression with
 * a specific number of operators to test the 300 operator limit.
 * 
 * @param {number} operationsCount - Number of operations to include
 * @returns {Object} - Object containing the update expression and attribute values
 */
function createComplexUpdateExpression(operationsCount) {
  // Initialize the expression parts and attribute values
  const setOperations = [];
  const expressionAttributeValues = {};
  
  // Generate the specified number of SET operations
  for (let i = 0; i < operationsCount; i++) {
    // Alternate between different types of SET operations
    let operation;
    const valueKey = `:val${i}`;
    
    switch (i % 3) {
      case 0:
        // Simple assignment (1 operator: =)
        operation = `attribute${i} = ${valueKey}`;
        expressionAttributeValues[valueKey] = `value${i}`;
        break;
      case 1:
        // Addition (2 operators: = and +)
        operation = `attribute${i} = attribute${i} + ${valueKey}`;
        expressionAttributeValues[valueKey] = i;
        break;
      case 2:
        // Conditional assignment with if_not_exists (2 operators: = and if_not_exists)
        operation = `attribute${i} = if_not_exists(attribute${i}, ${valueKey})`;
        expressionAttributeValues[valueKey] = i * 10;
        break;
    }
    
    setOperations.push(operation);
  }
  
  // Create the update expression
  const updateExpression = `SET ${setOperations.join(", ")}`;
  
  // Calculate the operator count
  // Each operation has 1-2 operators as noted above
  let operatorCount = 0;
  for (let i = 0; i < operationsCount; i++) {
    operatorCount += (i % 3 === 0) ? 1 : 2;
  }
  
  return {
    updateExpression,
    expressionAttributeValues,
    operatorCount
  };
}

/**
 * Test the operator limit by attempting an operation with a complex expression.
 * 
 * This function demonstrates what happens when an expression approaches or
 * exceeds the 300 operator limit.
 * 
 * @param {Object} config - AWS configuration object
 * @param {string} tableName - The name of the DynamoDB table
 * @param {Object} key - The key of the item to update
 * @param {number} operatorCount - Target number of operators to include
 * @returns {Promise<Object>} - Result of the operation attempt
 */
async function testOperatorLimit(
  config,
  tableName,
  key,
  operatorCount
) {
  // Initialize the DynamoDB client
  const client = new DynamoDBClient(config);
  const docClient = DynamoDBDocumentClient.from(client);
  
  // Create a complex update expression with the specified operator count
  const { updateExpression, expressionAttributeValues, operatorCount: actualCount } = 
    createComplexUpdateExpression(Math.ceil(operatorCount / 1.5)); // Adjust to get close to target count
  
  console.log(`Generated update expression with approximately ${actualCount} operators`);
  
  // Define the update parameters
  const params = {
    TableName: tableName,
    Key: key,
    UpdateExpression: updateExpression,
    ExpressionAttributeValues: expressionAttributeValues,
    ReturnValues: "UPDATED_NEW"
  };
  
  try {
    // Attempt the update operation
    const response = await docClient.send(new UpdateCommand(params));
    return {
      success: true,
      message: `Operation succeeded with ${actualCount} operators`,
      data: response
    };
  } catch (error) {
    // Check if the error is due to exceeding the operator limit
    if (error.name === "ValidationException" && 
        error.message.includes("too many operators")) {
      return {
        success: false,
        message: `Operation failed: ${error.message}`,
        operatorCount: actualCount
      };
    }
    
    // Return other errors
    return {
      success: false,
      message: `Operation failed: ${error.message}`,
      error
    };
  }
}

/**
 * Break down a complex expression into multiple simpler operations.
 * 
 * This function demonstrates how to handle expressions that would exceed
 * the 300 operator limit by breaking them into multiple operations.
 * 
 * @param {Object} config - AWS configuration object
 * @param {string} tableName - The name of the DynamoDB table
 * @param {Object} key - The key of the item to update
 * @param {number} totalOperations - Total number of operations to perform
 * @returns {Promise<Object>} - Result of the operations
 */
async function breakDownComplexExpression(
  config,
  tableName,
  key,
  totalOperations
) {
  // Initialize the DynamoDB client
  const client = new DynamoDBClient(config);
  const docClient = DynamoDBDocumentClient.from(client);
  
  // Calculate how many operations we can safely include in each batch
  // Using 150 as a conservative limit (well below 300)
  const operationsPerBatch = 100;
  const batchCount = Math.ceil(totalOperations / operationsPerBatch);
  
  console.log(`Breaking down ${totalOperations} operations into ${batchCount} batches`);
  
  const results = [];
  
  // Process each batch
  for (let batch = 0; batch < batchCount; batch++) {
    // Calculate the operations for this batch
    const batchStart = batch * operationsPerBatch;
    const batchEnd = Math.min(batchStart + operationsPerBatch, totalOperations);
    const batchSize = batchEnd - batchStart;
    
    console.log(`Processing batch ${batch + 1}/${batchCount} with ${batchSize} operations`);
    
    // Create an update expression for this batch
    const { updateExpression, expressionAttributeValues, operatorCount } = 
      createComplexUpdateExpression(batchSize);
    
    // Define the update parameters
    const params = {
      TableName: tableName,
      Key: key,
      UpdateExpression: updateExpression,
      ExpressionAttributeValues: expressionAttributeValues,
      ReturnValues: "UPDATED_NEW"
    };
    
    try {
      // Perform the update operation for this batch
      const response = await docClient.send(new UpdateCommand(params));
      
      results.push({
        batch: batch + 1,
        success: true,
        operatorCount,
        attributes: response.Attributes
      });
    } catch (error) {
      results.push({
        batch: batch + 1,
        success: false,
        operatorCount,
        error: error.message
      });
      
      // Stop processing if an error occurs
      break;
    }
  }
  
  return {
    totalBatches: batchCount,
    results
  };
}

/**
 * Count operators in a DynamoDB expression based on the rules in the documentation.
 * 
 * This function demonstrates how operators are counted according to the
 * DynamoDB documentation.
 * 
 * @param {string} expression - The DynamoDB expression to analyze
 * @returns {Object} - Breakdown of operator counts
 */
function countOperatorsInExpression(expression) {
  // Initialize counters for different operator types
  const counts = {
    comparisonOperators: 0,
    logicalOperators: 0,
    functions: 0,
    arithmeticOperators: 0,
    specialOperators: 0,
    total: 0
  };
  
  // Count comparison operators (=, <>, <, <=, >, >=)
  const comparisonRegex = /[^<>]=[^=]|<>|<=|>=|[^<]>[^=]|[^>]<[^=]/g;
  const comparisonMatches = expression.match(comparisonRegex) || [];
  counts.comparisonOperators = comparisonMatches.length;
  
  // Count logical operators (AND, OR, NOT)
  const andMatches = expression.match(/\bAND\b/g) || [];
  const orMatches = expression.match(/\bOR\b/g) || [];
  const notMatches = expression.match(/\bNOT\b/g) || [];
  counts.logicalOperators = andMatches.length + orMatches.length + notMatches.length;
  
  // Count functions (attribute_exists, attribute_not_exists, attribute_type, begins_with, contains, size)
  const functionRegex = /\b(attribute_exists|attribute_not_exists|attribute_type|begins_with|contains|size|if_not_exists)\(/g;
  const functionMatches = expression.match(functionRegex) || [];
  counts.functions = functionMatches.length;
  
  // Count arithmetic operators (+ and -)
  const arithmeticMatches = expression.match(/[a-zA-Z0-9_)\]]\s*[\+\-]\s*[a-zA-Z0-9_(:]/g) || [];
  counts.arithmeticOperators = arithmeticMatches.length;
  
  // Count special operators (BETWEEN, IN)
  const betweenMatches = expression.match(/\bBETWEEN\b/g) || [];
  const inMatches = expression.match(/\bIN\b/g) || [];
  counts.specialOperators = betweenMatches.length + inMatches.length;
  
  // Add extra operators for BETWEEN (each BETWEEN includes an AND)
  counts.logicalOperators += betweenMatches.length;
  
  // Calculate total
  counts.total = counts.comparisonOperators + 
                 counts.logicalOperators + 
                 counts.functions + 
                 counts.arithmeticOperators + 
                 counts.specialOperators;
  
  return counts;
}
```
Example usage of expression operator counting with AWS SDK for JavaScript.  

```
/**
 * Example of how to work with expression operator counting.
 */
async function exampleUsage() {
  // Example parameters
  const config = { region: "us-west-2" };
  const tableName = "Products";
  const key = { ProductId: "P12345" };
  
  console.log("Demonstrating DynamoDB expression operator counting and the 300 operator limit");
  
  try {
    // Example 1: Analyze a simple expression
    console.log("\nExample 1: Analyzing a simple expression");
    const simpleExpression = "Price = :price AND Rating > :rating AND Category IN (:cat1, :cat2, :cat3)";
    const simpleCount = countOperatorsInExpression(simpleExpression);
    
    console.log(`Expression: ${simpleExpression}`);
    console.log("Operator count breakdown:");
    console.log(`- Comparison operators: ${simpleCount.comparisonOperators}`);
    console.log(`- Logical operators: ${simpleCount.logicalOperators}`);
    console.log(`- Functions: ${simpleCount.functions}`);
    console.log(`- Arithmetic operators: ${simpleCount.arithmeticOperators}`);
    console.log(`- Special operators: ${simpleCount.specialOperators}`);
    console.log(`- Total operators: ${simpleCount.total}`);
    
    // Example 2: Analyze a complex expression
    console.log("\nExample 2: Analyzing a complex expression");
    const complexExpression = 
      "(attribute_exists(Category) AND Size BETWEEN :min AND :max) OR " +
      "(Price > :price AND contains(Description, :keyword) AND " +
      "(Rating >= :minRating OR Reviews > :minReviews))";
    const complexCount = countOperatorsInExpression(complexExpression);
    
    console.log(`Expression: ${complexExpression}`);
    console.log("Operator count breakdown:");
    console.log(`- Comparison operators: ${complexCount.comparisonOperators}`);
    console.log(`- Logical operators: ${complexCount.logicalOperators}`);
    console.log(`- Functions: ${complexCount.functions}`);
    console.log(`- Arithmetic operators: ${complexCount.arithmeticOperators}`);
    console.log(`- Special operators: ${complexCount.specialOperators}`);
    console.log(`- Total operators: ${complexCount.total}`);
    
    // Example 3: Test approaching the operator limit
    console.log("\nExample 3: Testing an expression approaching the operator limit");
    const approachingLimit = await testOperatorLimit(config, tableName, key, 290);
    console.log(approachingLimit.message);
    
    // Example 4: Test exceeding the operator limit
    console.log("\nExample 4: Testing an expression exceeding the operator limit");
    const exceedingLimit = await testOperatorLimit(config, tableName, key, 310);
    console.log(exceedingLimit.message);
    
    // Example 5: Breaking down a complex expression
    console.log("\nExample 5: Breaking down a complex expression into multiple operations");
    const breakdownResult = await breakDownComplexExpression(config, tableName, key, 500);
    console.log(`Processed ${breakdownResult.results.length} of ${breakdownResult.totalBatches} batches`);
    
    // Explain the operator counting rules
    console.log("\nKey points about DynamoDB expression operator counting:");
    console.log("1. The maximum number of operators in any expression is 300");
    console.log("2. Each comparison operator (=, <>, <, <=, >, >=) counts as 1 operator");
    console.log("3. Each logical operator (AND, OR, NOT) counts as 1 operator");
    console.log("4. Each function call (attribute_exists, contains, etc.) counts as 1 operator");
    console.log("5. Each arithmetic operator (+ or -) counts as 1 operator");
    console.log("6. BETWEEN counts as 2 operators (BETWEEN itself and the AND within it)");
    console.log("7. IN counts as 1 operator regardless of the number of values");
    console.log("8. Parentheses for grouping and attribute paths don't count as operators");
    console.log("9. When you exceed the limit, the error always reports '301 operators'");
    console.log("10. For complex operations, break them into multiple smaller operations");
    
  } catch (error) {
    console.error("Error:", error);
  }
}
```
+  For API details, see [UpdateItem](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/dynamodb/command/UpdateItemCommand) in *AWS SDK for JavaScript API Reference*. 

------
#### [ Python ]

**SDK for Python (Boto3)**  
Demonstrate expression operator counting using AWS SDK for Python (Boto3).  

```
import boto3
from botocore.exceptions import ClientError
from typing import Any, Dict, List, Optional, Tuple



def create_complex_filter_expression(
    attribute_name: str, values: List[Any], use_or: bool = True
) -> Tuple[str, Dict[str, Any], Dict[str, str], int]:
    """
    Create a complex filter expression with multiple conditions.

    This function demonstrates how to build a complex filter expression
    and count the number of operators used.

    Args:
        attribute_name (str): The name of the attribute to filter on.
        values (List[Any]): List of values to compare against.
        use_or (bool, optional): Whether to use OR between conditions. Defaults to True.

    Returns:
        Tuple[str, Dict[str, Any], Dict[str, str], int]: A tuple containing:
            - The filter expression string
            - Expression attribute values
            - Expression attribute names
            - The number of operators used
    """
    if not values:
        return "", {}, {}, 0

    # Initialize expression components
    filter_expression = ""
    expression_attribute_values = {}
    expression_attribute_names = {"#attr": attribute_name}
    operator_count = 0

    # Build the filter expression
    for i, value in enumerate(values):
        value_placeholder = f":val{i}"
        expression_attribute_values[value_placeholder] = value

        if i > 0:
            # Add OR or AND operator between conditions
            filter_expression += " OR " if use_or else " AND "
            operator_count += 1  # Count the OR/AND operator

        # Add the condition
        filter_expression += f"#attr = {value_placeholder}"
        operator_count += 1  # Count the = operator

    return (
        filter_expression,
        expression_attribute_values,
        expression_attribute_names,
        operator_count,
    )


def create_nested_filter_expression(
    depth: int, conditions_per_level: int
) -> Tuple[str, Dict[str, Any], Dict[str, str], int]:
    """
    Create a deeply nested filter expression with multiple conditions.

    This function demonstrates how to build a complex nested filter expression
    and count the number of operators used.

    Args:
        depth (int): The depth of nesting.
        conditions_per_level (int): Number of conditions at each level.

    Returns:
        Tuple[str, Dict[str, Any], Dict[str, str], int]: A tuple containing:
            - The filter expression string
            - Expression attribute values
            - Expression attribute names
            - The number of operators used
    """
    if depth <= 0 or conditions_per_level <= 0:
        return "", {}, {}, 0

    # Initialize expression components
    expression_attribute_values = {}
    expression_attribute_names = {}
    operator_count = 0

    def build_nested_expression(current_depth: int, prefix: str) -> str:
        nonlocal operator_count

        if current_depth <= 0:
            return ""

        # Build conditions at this level
        conditions = []
        for i in range(conditions_per_level):
            attr_name = f"attr{prefix}_{i}"
            attr_placeholder = f"#attr{prefix}_{i}"
            val_placeholder = f":val{prefix}_{i}"

            expression_attribute_names[attr_placeholder] = attr_name
            expression_attribute_values[val_placeholder] = i

            conditions.append(f"{attr_placeholder} = {val_placeholder}")
            operator_count += 1  # Count the = operator

        # Join conditions with AND
        level_expression = " AND ".join(conditions)
        operator_count += max(0, len(conditions) - 1)  # Count the AND operators

        # If not at the deepest level, add nested expressions
        if current_depth > 1:
            nested_expr = build_nested_expression(current_depth - 1, f"{prefix}_{current_depth}")
            if nested_expr:
                level_expression = f"({level_expression}) OR ({nested_expr})"
                operator_count += 1  # Count the OR operator

        return level_expression

    # Build the expression starting from the top level
    filter_expression = build_nested_expression(depth, "1")

    return (
        filter_expression,
        expression_attribute_values,
        expression_attribute_names,
        operator_count,
    )


def count_operators_in_update_expression(update_expression: str) -> int:
    """
    Count the number of operators in an update expression.

    This function demonstrates how to count operators in an update expression
    based on DynamoDB's rules.

    Args:
        update_expression (str): The update expression to analyze.

    Returns:
        int: The number of operators in the expression.
    """
    operator_count = 0

    # Count SET operations
    if "SET" in update_expression:
        set_section = (
            update_expression.split("SET")[1].split("REMOVE")[0].split("ADD")[0].split("DELETE")[0]
        )

        # Count assignment operators (=)
        operator_count += set_section.count("=")

        # Count arithmetic operators (+, -)
        operator_count += set_section.count("+")
        operator_count += set_section.count("-")

        # Count list_append function calls (each counts as 1 operator)
        operator_count += set_section.lower().count("list_append")

        # Count if_not_exists function calls (each counts as 1 operator)
        operator_count += set_section.lower().count("if_not_exists")

    # Count REMOVE operations (no additional operators)

    # Count ADD operations (each ADD counts as 1 operator)
    if "ADD" in update_expression:
        add_section = (
            update_expression.split("ADD")[1].split("DELETE")[0].split("SET")[0].split("REMOVE")[0]
        )
        operator_count += add_section.count(",") + 1

    # Count DELETE operations (each DELETE counts as 1 operator)
    if "DELETE" in update_expression:
        delete_section = (
            update_expression.split("DELETE")[1].split("SET")[0].split("ADD")[0].split("REMOVE")[0]
        )
        operator_count += delete_section.count(",") + 1

    return operator_count


def count_operators_in_condition_expression(condition_expression: str) -> int:
    """
    Count the number of operators in a condition expression.

    This function demonstrates how to count operators in a condition expression
    based on DynamoDB's rules.

    Args:
        condition_expression (str): The condition expression to analyze.

    Returns:
        int: The number of operators in the expression.
    """
    operator_count = 0

    # Count comparison operators
    comparison_operators = ["=", "<>", "<", "<=", ">", ">="]
    for op in comparison_operators:
        operator_count += condition_expression.count(op)

    # Count logical operators
    operator_count += condition_expression.upper().count(" AND ")
    operator_count += condition_expression.upper().count(" OR ")
    operator_count += condition_expression.upper().count("NOT ")

    # Count BETWEEN operator (counts as 2: BETWEEN + AND)
    between_count = condition_expression.upper().count(" BETWEEN ")
    operator_count += between_count * 2

    # Count IN operator (counts as 1 regardless of number of values)
    operator_count += condition_expression.upper().count(" IN ")

    # Count functions (each counts as 1 operator)
    functions = [
        "attribute_exists",
        "attribute_not_exists",
        "attribute_type",
        "begins_with",
        "contains",
        "size",
    ]
    for func in functions:
        operator_count += condition_expression.lower().count(func)

    return operator_count


# Note: This function is for demonstration purposes only and should be called from example_usage()
# It's not meant to be used directly as a test function
def _test_expression_limit(
    table_name: str, key: Dict[str, Any], operator_count: int, attribute_name: str = "TestAttribute"
) -> Tuple[bool, Optional[str]]:
    """
    Test if an expression with a specific number of operators exceeds the limit.

    This function demonstrates how to test the 300 operator limit by creating
    an expression with a specified number of operators.

    Args:
        table_name (str): The name of the DynamoDB table.
        key (Dict[str, Any]): The primary key of the item to update.
        operator_count (int): The number of operators to include in the expression.
        attribute_name (str, optional): The name of the attribute to update. Defaults to "TestAttribute".

    Returns:
        Tuple[bool, Optional[str]]: A tuple containing:
            - A boolean indicating if the operation succeeded
            - The error message if it failed, None otherwise
    """
    # Initialize the DynamoDB resource
    dynamodb = boto3.resource("dynamodb")
    table = dynamodb.Table(table_name)

    # Create an update expression with the specified number of operators
    update_expression = f"SET #{attribute_name} = :val0"
    expression_attribute_names = {f"#{attribute_name}": attribute_name}
    expression_attribute_values = {":val0": 0}

    # Add additional SET operations to reach the desired operator count
    # Each assignment adds 1 operator
    for i in range(1, operator_count):
        attr_name = f"{attribute_name}{i}"
        attr_placeholder = f"#attr{i}"
        val_placeholder = f":val{i}"

        update_expression += f", {attr_placeholder} = {val_placeholder}"
        expression_attribute_names[attr_placeholder] = attr_name
        expression_attribute_values[val_placeholder] = i

    try:
        # Attempt the update operation
        table.update_item(
            Key=key,
            UpdateExpression=update_expression,
            ExpressionAttributeNames=expression_attribute_names,
            ExpressionAttributeValues=expression_attribute_values,
        )
        return True, None
    except ClientError as e:
        error_message = e.response["Error"]["Message"]

        if "expression contains too many operators" in error_message.lower():
            return False, error_message
        else:
            # Other error occurred
            raise
```
Example usage of expression operator counting with AWS SDK for Python (Boto3).  

```
def example_usage():
    """Example of how to use the expression operator counting functions."""

    print("Example 1: Creating a complex filter expression with multiple conditions")
    attribute_name = "Status"
    values = ["Active", "Pending", "Processing", "Shipped", "Delivered"]

    filter_expr, expr_attr_vals, expr_attr_names, op_count = create_complex_filter_expression(
        attribute_name=attribute_name, values=values, use_or=True
    )

    print(f"Filter Expression: {filter_expr}")
    print(f"Expression Attribute Values: {expr_attr_vals}")
    print(f"Expression Attribute Names: {expr_attr_names}")
    print(f"Operator Count: {op_count}")

    print("\nExample 2: Creating a nested filter expression")
    nested_expr, nested_vals, nested_names, nested_count = create_nested_filter_expression(
        depth=3, conditions_per_level=2
    )

    print(f"Nested Filter Expression: {nested_expr}")
    print(f"Operator Count: {nested_count}")

    print("\nExample 3: Counting operators in an update expression")
    update_expression = "SET #name = :name, #age = :age + :increment, #address.#city = :city, #status = if_not_exists(#status, :default_status) REMOVE #old_field ADD #counter :value DELETE #set_attr :set_val"
    update_op_count = count_operators_in_update_expression(update_expression)

    print(f"Update Expression: {update_expression}")
    print(f"Operator Count: {update_op_count}")

    print("\nExample 4: Counting operators in a condition expression")
    condition_expression = "(#status = :active OR #status = :pending) AND #price BETWEEN :min_price AND :max_price AND attribute_exists(#category) AND NOT (#stock <= :min_stock)"
    condition_op_count = count_operators_in_condition_expression(condition_expression)

    print(f"Condition Expression: {condition_expression}")
    print(f"Operator Count: {condition_op_count}")

    print("\nExample 5: Testing the 300 operator limit")

    # This is just for demonstration - in a real application, you would use your actual table
    # Note: This function is renamed to _test_expression_limit to avoid pytest trying to run it
    print("In a real application, you would test with _test_expression_limit function")
    print("Expression with 250 operators would be under the limit")
    print("Expression with 350 operators would exceed the 300 operator limit")

    print("\nOperator Counting Rules in DynamoDB:")
    print("1. Comparison Operators (=, <>, <, <=, >, >=): 1 operator each")
    print("2. Logical Operators (AND, OR, NOT): 1 operator each")
    print("3. BETWEEN: 2 operators (BETWEEN + AND)")
    print("4. IN: 1 operator (regardless of number of values)")
    print("5. Functions (attribute_exists, begins_with, etc.): 1 operator each")
    print("6. Arithmetic Operators (+, -): 1 operator each")
    print("7. SET assignments (=): 1 operator each")
    print("8. ADD and DELETE operations: 1 operator each")

    print("\nStrategies for Working Within the 300 Operator Limit:")
    print("1. Break operations into multiple requests")
    print("2. Use DynamoDB Transactions for complex operations")
    print("3. Optimize data model to reduce query complexity")
    print("4. Use application-side filtering for less critical filters")
    print("5. Consider using IN operator instead of multiple OR conditions")
```
+  For API details, see [UpdateItem](https://docs.aws.amazon.com/goto/boto3/dynamodb-2012-08-10/UpdateItem) in *AWS SDK for Python (Boto3) API Reference*. 

------

For a complete list of AWS SDK developer guides and code examples, see [Using DynamoDB with an AWS SDK](sdk-general-information-section.md). This topic also includes information about getting started and details about previous SDK versions.