Database Connections

-- E-commerce Database Schema
products (
  id: serial primary key,
  name: varchar(255),      -- Product display name
  price: decimal(10,2),    -- Current selling price
  stock: integer,          -- Available quantity in inventory
  category_id: integer references categories(id)  -- Product classification
)

categories (
  id: serial primary key,
  name: varchar(100),      -- Category display name
  description: text        -- Detailed category description
)

-- Orders can have multiple products
orders (
  id: serial primary key,
  customer_id: integer,    -- References customer making the purchase
  order_date: timestamp,   -- When the order was placed
  status: varchar(50)      -- Current order status (pending, shipped, delivered, etc.)
)

# School Management System
students (
  id: int auto_increment primary key,
  first_name: varchar(50),
  last_name: varchar(50),
  date_of_birth: date,     # Used for age verification and reports
  grade: int,              # Current grade level
  email: varchar(100) unique  # Primary contact method for students
)

courses (
  id: int auto_increment primary key,
  name: varchar(100),      # Full course title
  credits: int,            # Number of credits awarded
  department: varchar(50)  # Academic department offering the course
)

# Junction table for many-to-many relationship
enrollments (
  student_id: int,
  course_id: int,
  enrollment_date: datetime,  # When student enrolled in the course
  grade: decimal(4,2)        # Final grade achieved (0.00-100.00)
)

// Blog Platform
posts: {
  _id: ObjectId,
  title: String,           // Post headline
  content: String,         // Main post content
  author: {
    _id: ObjectId,
    name: String,         // Author's display name
    email: String         // Author's contact email
  },
  tags: Array<String>,    // Categories/topics for the post
  comments: [{
    user: String,         // Commenter's username
    content: String,      // Comment text
    created_at: Date      // When comment was posted
  }],
  created_at: Date,       // When post was first published
  updated_at: Date        // Last modification timestamp
}

users: {
  _id: ObjectId,
  username: String,       // Unique username for login
  email: String,         // Primary contact method
  profile: {
    bio: String,         // User's self description
    avatar_url: String,  // Profile picture URL
    social_links: {
      twitter: String,   // Twitter profile URL
      github: String     // GitHub profile URL
    }
  }
}