DBConnection Class Documentation

Overview

The DBConnection class is designed to facilitate interactions with a PostgreSQL database, providing methods for connecting to the database, performing CRUD operations, and fetching schema information.

Constructor

DBConnection()

Initializes a new instance of the DBConnection class.

Methods

async ConnectPG(login)

• Establishes a connection to the PostgreSQL database.
• Parameters:
  • login (Object): Configuration for database connection.
• Returns: Promise that resolves upon establishing the connection.

async GetPG(table, where = "", values = [], select = "*", output = false)

• Retrieves data from a specified table.
• Parameters:
  • table (String): Table name.
  • where (String, optional): WHERE clause.
  • values (Array, optional): Parameterized query values.
  • select (String, optional): Columns to select.
  • output (Boolean, optional): Modify query result.
• Returns: Promise with the query result.

async SetPG(array, whereValues, table)

• Updates data in a specified table.
• Parameters:
  • array (Array): Data to update.
  • whereValues (Array|String): Update criteria.
  • table (String): Table name.
• Returns: Promise that resolves upon completion.

async InsertPG(array, table, toReturn = "")

• Inserts data into a specified table.
• Parameters:
  • array (Array): Data to insert.
  • table (String): Table name.
  • toReturn (String, optional): Columns to return.
• Returns: Promise with inserted data or success message.

async DeletePG(table, where = "", values = [], safety = true)

• Deletes data from a specified table.
• Parameters:
  • table (String): Table name.
  • where (String, optional): WHERE clause.
  • values (Array, optional): Parameterized query values.
  • safety (Boolean, optional): Execute safety check.
• Returns: Promise that resolves upon completion.

async getSchemaPG(table)

• Fetches schema information for a specified table.
• Parameters:
  • table (String): Table name.
• Returns: Promise with schema details.

async DisconnectPG()

• Disconnects from the PostgreSQL database.
• Returns: Promise that resolves upon disconnection.

Example Usage

const db = new DBConnection();

// Establish a connection to the database
const loginConfig = {
    user: 'your_username',
    password: 'your_password',
    host: 'localhost',
    port: 5432,
    database: 'your_database'
};
await db.ConnectPG(loginConfig);

// Retrieve data from a table
const userData = await db.GetPG('users', 'age > $1', [18], 'name, age');
console.log('Users above 18:', userData.rows);

// Insert data into a table
const newUser = { name: 'Alice', age: 25 };
await db.InsertPG([newUser], 'users');
console.log('New user inserted.');

// Update data in a table
const updateCriteria = ['name']; // Match users with name "Alice"
const updatedData = {name:"Alice", age: 26 };
await db.SetPG([updatedData], updateCriteria , 'users');
console.log('User data updated.');

// Delete data from a table
const deleteCriteria = ['Bob']; // Match users with name "Bob"
await db.DeletePG('users', 'name = $1', deleteCriteria);
console.log('User data deleted.');

// Fetch schema information for a table
const schemaInfo = await db.getSchemaPG('users');
console.log('Schema Information:', schemaInfo);

// Disconnect from the database
await db.DisconnectPG();
console.log('Disconnected from the database.');

This documentation provides a comprehensive guide to utilizing the DBConnection class for managing database interactions within a Node.js application.