KORM (KSQL Object Relational Mapping)

KORM is a sophisticated TypeScript Object-Relational Mapping (ORM) library designed specifically for KSQL stream processing. It enables developers to build and execute KSQL queries using type-safe TypeScript objects instead of raw SQL strings, providing robust compile-time safety, excellent IDE support, and comprehensive validation.

Key Features

Type Safety & Validation

• 🛡️ Complete TypeScript type checking for query construction
• ✅ Comprehensive Zod schema validation
• 🔍 Runtime validation of complex query relationships
• 🚫 Prevention of SQL injection vulnerabilities

Query Building

• 🔄 Full support for KSQL streams and tables
• 🛠️ Rich set of transformation functions (string, numeric, date, aggregate)
• 📦 Composable query components
• 🔌 Seamless integration with existing KSQL deployments

Developer Experience

• 💡 Full IDE IntelliSense support
• 🔧 Refactoring-friendly design
• 📝 Clear version control diffs
• 📚 Extensive inline documentation

Installation

npm install @eleven-am/korm

Basic Usage

Client Setup

import { KsqlDBClient } from '@eleven-am/korm';

const client = new KsqlDBClient({
  host: 'localhost',
  port: 8088,
  protocol: 'http',
  auth: {
    username: 'user',
    password: 'pass'
  }
});

Simple Query Example

// Building a query to count orders
import { KSQLStatement } from './statements';

const countOrdersQuery: KSQLStatement = {
    type: SelectType.COLUMN,
    columns: [
        {
            type: SelectType.COLUMN,
            expression: {
                type: ExpressionType.TRANSFORMATION,
                value: {
                    type: TransformType.AGGREGATE,
                    function: AggregateFunction.COUNT,
                    parameters: []
                }
            },
            alias: 'total_orders'
        }
    ],
    from: {
        sourceType: DataSourceType.STREAM,
        source: {
            type: SourceType.DIRECT,
            name: 'orders',
            sourceType: DataSourceType.STREAM
        }
    },
    groupBy: {
        columns: []
    },
    emit: EmitType.CHANGES
};

// Equivalent SQL:

// SELECT COUNT(*) AS total_orders
// FROM orders
// GROUP BY
// EMIT CHANGES;

// Execute the query
const result = await client.executeStatement(countOrdersQuery);

Advanced Features

Complex Transformations

// Example of string and numeric transformations
const transformationExample = {
  type: TransformType.STRING,
  function: StringFunction.CONCAT,
  parameters: [/* parameters */]
};

Window Operations

// Example of a tumbling window
const windowedQuery = {
  window: {
    type: WindowType.TUMBLING,
    size: {
      value: 5,
      unit: WindowTimeUnit.MINUTES
    }
  }
};

Join Operations

// Example of stream-table join
const joinExample = {
  type: JoinType.INNER,
  source: {
    name: 'order_details',
    sourceType: DataSourceType.TABLE
  },
  conditions: [
    {
      leftField: 'order_id',
      rightField: 'id'
    }
  ]
};

Error Handling

KORM provides detailed error information through two main error types:

try {
  await client.executeStatement(query);
} catch (error) {
  if (error instanceof KsqlDBError) {
    // Handle server-side errors
    console.error('KSQL Error:', error.message);
  } else if (error instanceof ValidationError) {
    // Handle validation failures
    console.error('Validation Error:', error.details);
  }
}

Configuration Options

interface KsqlDBConfig {
  host: string;
  port: number;
  protocol?: 'http' | 'https';
  auth?: {
    username: string;
    password: string;
  };
  defaultStreamProperties?: {
    'ksql.streams.auto.offset.reset'?: 'earliest' | 'latest';
    'ksql.streams.cache.max.bytes.buffering'?: number;
    [key: string]: string | number | boolean | undefined;
  };
}

Contributing

We welcome contributions! Please see our Contributing Guide for details on:

• Code of Conduct
• Development setup
• Testing guidelines
• Pull request process

License

MIT

Support

• 📚 Documentation
• 💬 Discussions
• 🐛 Issue Tracker