meadow-connection-postgresql

PostgreSQL connection service for the Meadow data access layer.

Features

• Fable Service Provider -- integrates with the Fable dependency injection ecosystem
• Connection Pooling -- managed pool via the pg driver's Pool class
• SQL DDL Generation -- produces PostgreSQL-native CREATE TABLE and DROP TABLE statements
• Meadow-Compatible Settings -- accepts both Meadow-style (Server, Port) and native pg property names
• Quoted Identifiers -- double-quoted table and column names for safe handling of reserved words
• Auto-Connect Mode -- optionally connect during service construction
• Idempotent Schema -- CREATE TABLE IF NOT EXISTS and graceful handling of duplicate table errors

Installation

npm install meadow-connection-postgresql

Quick Start

const libFable = require('fable');
const libMeadowConnectionPostgreSQL = require('meadow-connection-postgresql');

let _Fable = new libFable(
	{
		"PostgreSQL":
		{
			"Server": "localhost",
			"Port": 5432,
			"User": "postgres",
			"Password": "secret",
			"Database": "myapp"
		}
	});

_Fable.serviceManager.addAndInstantiateServiceType(
	'MeadowPostgreSQLProvider', libMeadowConnectionPostgreSQL);

_Fable.MeadowPostgreSQLProvider.connectAsync(
	(pError, pPool) =>
	{
		if (pError) { return console.error(pError); }

		let tmpPool = _Fable.MeadowPostgreSQLProvider.pool;
		tmpPool.query('SELECT NOW()', (pErr, pRes) =>
		{
			console.log('Server time:', pRes.rows[0].now);
		});
	});

Configuration

Settings are read from fable.settings.PostgreSQL:

| Setting | Alias | Default | Description | |---------|-------|---------|-------------| | Server | host | -- | PostgreSQL host | | Port | port | -- | PostgreSQL port | | User | user | -- | Authentication username | | Password | password | -- | Authentication password | | Database | database | -- | Target database name | | ConnectionPoolLimit | max | -- | Maximum connections in the pool |

API

| Method | Description | |--------|-------------| | connect() | Synchronous -- create pg.Pool instance | | connectAsync(fCallback) | Callback-style connection (recommended) | | pool | Getter -- returns the pg.Pool instance | | generateCreateTableStatement(schema) | Generate a CREATE TABLE DDL string | | createTable(schema, fCallback) | Execute CREATE TABLE via the pool | | createTables(schema, fCallback) | Create multiple tables sequentially | | generateDropTableStatement(name) | Generate a DROP TABLE IF EXISTS DDL string |

Column Type Mapping

| Meadow DataType | PostgreSQL Type | Constraints | |-----------------|-----------------|-------------| | ID | SERIAL | PRIMARY KEY | | GUID | VARCHAR(Size) | DEFAULT '0xDe' | | ForeignKey | INTEGER | NOT NULL DEFAULT 0 | | Numeric | INTEGER | NOT NULL DEFAULT 0 | | Decimal | DECIMAL(Size) | -- | | String | VARCHAR(Size) | NOT NULL DEFAULT '' | | Text | TEXT | -- | | DateTime | TIMESTAMP | -- | | Boolean | BOOLEAN | NOT NULL DEFAULT false |

Part of the Retold Framework

This module is a Meadow connector that plugs into the Retold application framework. It provides the PostgreSQL persistence layer for the Meadow data access abstraction.

Testing

npm test

Coverage:

npm run coverage

Related Packages

• meadow -- Data access layer and ORM
• fable -- Application framework and service manager
• foxhound -- Query generation DSL
• stricture -- Schema definition and DDL tools
• meadow-endpoints -- RESTful endpoint generation
• meadow-connection-mysql -- MySQL / MariaDB connector
• meadow-connection-mssql -- Microsoft SQL Server connector
• meadow-connection-sqlite -- SQLite connector
• meadow-connection-mongodb -- MongoDB connector

License

MIT

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.