database-design

name	database-design
description	MongoDB/Mongoose schema design, indexing, relationships, query patterns for Resource-Adda. Use when designing data models, creating Mongoose schemas, optimizing queries, or setting up database connections.

Database Design

When to Use

• Designing data models for new features
• Creating Mongoose schemas
• Optimizing query performance
• Planning indexing strategies
• Setting up database connections

Procedure

Phase 1: Schema Design

Resource-Adda uses MongoDB with Mongoose for all data persistence.

import mongoose from "mongoose";

const vendorSchema = new mongoose.Schema(
  {
    name: { type: String, required: true, trim: true },
    category: {
      type: String,
      required: true,
      enum: ["catering", "technology", "venue", "equipment", "other"],
    },
    contactPerson: { type: String, required: true },
    email: { type: String, required: true, lowercase: true },
    phone: { type: String, required: true },
    status: {
      type: String,
      default: "active",
      enum: ["active", "inactive", "suspended"],
    },
    rating: { type: Number, default: 0, min: 0, max: 5 },
  },
  { timestamps: true },
);

export const Vendor = mongoose.model("Vendor", vendorSchema);

Rules:

• Always use timestamps: true for createdAt/updatedAt
• Use enums for constrained values
• Mark required: true explicitly
• Use trim: true on strings, lowercase: true on emails

Phase 2: Schema Locations

• Operations modules (vendor, resource, scheduling, budget): backend/src/database/schemas/
• Other modules: apps/<module>/src/schema/

Phase 3: Indexing Strategy

• Index primary lookup fields (email, status, category)
• Index sort fields (createdAt, updatedAt)
• Use unique: true for emails where appropriate
• Avoid indexing low-cardinality booleans
• Monitor slow queries with mongoose.set('debug', true)

Phase 4: Relationship Patterns

• One-to-Many: Reference ID on the "many" side (eventId in registrations)
• Embedded: For data always fetched together
• Cross-module: Reference IDs only — never import from other modules

Phase 5: Connection Configuration

// database/connection.js
const options = {
  serverSelectionTimeoutMS: 5000,
  socketTimeoutMS: 45000,
  maxPoolSize: 10,
  minPoolSize: 2,
};

Default URI: mongodb://localhost:27017/Resource-Adda

Quick Reference

# Start MongoDB
docker run -d -p 27017:27017 --name mongodb mongo:latest

# Connect to shell
mongosh mongodb://localhost:27017/Resource-Adda

# Check connection from backend
curl http://localhost:4000/health

Common Issues

Issue	Solution
Connection refused	Ensure MongoDB is running (docker start mongodb)
Validation error	Check required fields and enum values in schema
Slow queries	Add indexes on filter/sort fields
Duplicate key	Check unique: true indexes, handle in service