db_client

A production-ready Dart package for connecting to SQL Server, Oracle, and PostgreSQL via ODBC. Battle-tested for concurrent workloads and long-running servers.

Forked from dart_odbc, enhanced for production stability.

Version 0.2.1

Fixes:

• Eliminates heap corruption crashes on process exit
• SQL Server: Exit code 0 (fully resolved)
• Oracle: Functional, known exit code issue (doesn't affect production)

Memory Strategy:
Resources persist until process termination to prevent ODBC driver cleanup issues. Impact: ~516 bytes per connection.

Ideal for: Long-running servers with singleton pattern (1-10 permanent connections).

Quick Start

SQL Server

import 'package:db_client/db_client.dart';

final client = SqlDbClient(DbClientConfig(
  driver: 'ODBC Driver 17 for SQL Server',
  server: 'localhost',
  database: 'my_database',
  username: 'sa',
  password: 'password',
  additionalParams: {
    'Encrypt': 'no',
    'TrustServerCertificate': 'yes',
  },
));

// Execute query
final result = await client.send(
  DbRequest.query('SELECT * FROM users WHERE id = ?', params: [1]),
);

if (result.success) {
  print(result.rows);
}

Oracle

final client = SqlDbClient(DbClientConfig(
  driver: 'Oracle in instantclient_21_17',
  server: '',  // Leave empty
  port: 0,
  username: 'system',
  password: 'password',
  additionalParams: {
    'DBQ': 'localhost:1521/XEPDB1',  // host:port/service
  },
));

final result = await client.send(
  DbRequest.query('SELECT * FROM users WHERE id = ?', params: [1]),
);

PostgreSQL

Functional, but not testted in production.

Resource Management (v0.2.1+)

The close() method is optional. Resources are automatically cleaned up on process exit.

Recommended pattern:

// Singleton - never call close()
class Database {
  static SqlDbClient? _instance;
  
  static SqlDbClient get instance {
    _instance ??= SqlDbClient(config);
    return _instance!;
  }
}

Memory impact: ~516 bytes per connection retained until process exit.

Features

• SQL Server: Full support (ODBC Driver 17+)
• Oracle: Full support (Instant Client 19c/21c)
• PostgreSQL: Coming soon
• Parameterized queries: SQL injection prevention
• Concurrent connections: Tested with 6+ simultaneous connections
• Production-ready: Ideal for long-running servers

Additional Information

For more about ODBC, see the Microsoft ODBC documentation.