# Mega Mart Grocery

## Schema Overview

The `MEGA_MART_GROCERY` database underpins the core operations of a grocery retail system, managing product categories, customer information, employee details, and sales orders including individual order items.

## Table Summary

| Table Name | Primary Responsibility |
| :--------- | :--------------------- |
| `Categories` | Organizes products into distinct categories for efficient inventory management and customer Browse. |
| `Customers` | Stores comprehensive information about all registered customers. |
| `Employees` | Contains details of all employees involved in the grocery operations. |
| `OrderDetails` | Links products to specific orders, defining the quantity of each item purchased. |
| `Orders` | Records each customer order, including who placed it, who processed it, and when. |
| `Products` | Manages the catalog of all items available for sale within the grocery store. |
| `Shippers` | Stores information about the companies responsible for delivering orders. |
| `Suppliers` | Maintains details of all product suppliers. |

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## `Categories` Table

This table defines the various categories under which products are grouped. It is essential for organizing the product catalog and enabling filtered searches within the application.

| Column Name | Data Type | Description |
| :---------- | :-------- | :---------- |
| `CategoryID` | INT | Unique identifier for this entity. Used for all lookups and relationships. |
| `CategoryName` | VARCHAR(25) (Optional) | The name of the product category. |
| `Description` | VARCHAR(255) (Optional) | A brief explanation of the category. |

## `Customers` Table

This table holds the master data for all customers. It is crucial for order processing, customer relationship management, and personalized services.

| Column Name | Data Type | Description |
| :---------- | :-------- | :---------- |
| `CustomerID` | INT | Unique identifier for this entity. Used for all lookups and relationships. |
| `CustomerName` | VARCHAR(50) (Optional) | The full name of the customer. |
| `ContactName` | VARCHAR(50) (Optional) | The name of the primary contact person for the customer. |
| `Address` | VARCHAR(50) (Optional) | The customer's street address. |
| `City` | VARCHAR(20) (Optional) | The city where the customer resides. |
| `PostalCode` | VARCHAR(10) (Optional) | The postal code for the customer's address. |
| `Country` | VARCHAR(15) (Optional) | The country where the customer resides. |

## `Employees` Table

This table stores information about the employees of the grocery store. This data is used to track who processed an order and for internal HR functions.

| Column Name | Data Type | Description |
| :---------- | :-------- | :---------- |
| `EmployeeID` | INT | Unique identifier for this entity. Used for all lookups and relationships. |
| `LastName` | VARCHAR(15) (Optional) | The employee's last name. |
| `FirstName` | VARCHAR(15) (Optional) | The employee's first name. |
| `BirthDate` | DATETIME (Optional) | The employee's birth date. Map to `java.time.LocalDateTime` for modern date/time handling. |
| `Photo` | VARCHAR(25) (Optional) | File path or reference to the employee's photo. |
| `Notes` | VARCHAR(1024) (Optional) | General notes or additional information about the employee. |

## `OrderDetails` Table

This table captures the individual items within each order. It establishes a many-to-many relationship between orders and products, detailing quantities.

| Column Name | Data Type | Description |
| :---------- | :-------- | :---------- |
| `OrderDetailID` | INT | Unique identifier for this entity. Used for all lookups and relationships. |
| `OrderID` | INT (Optional) | Establishes a relationship with `Orders.OrderID`. Essential for data integrity and joins. |
| `ProductID` | INT (Optional) | Establishes a relationship with `Products.ProductID`. Essential for data integrity and joins. |
| `Quantity` | INT (Optional) | The number of units of the product included in this order detail. |

## `Orders` Table

This table records each transaction made by customers. It links customers, employees, and shippers to specific orders, providing a complete overview of each sale.

| Column Name | Data Type | Description |
| :---------- | :-------- | :---------- |
| `OrderID` | INT | Unique identifier for this entity. Used for all lookups and relationships. |
| `CustomerID` | INT (Optional) | Establishes a relationship with `Customers.CustomerID`. Essential for data integrity and joins. |
| `EmployeeID` | INT (Optional) | Establishes a relationship with `Employees.EmployeeID`. Essential for data integrity and joins. |
| `OrderDate` | DATETIME (Optional) | The date and time the order was placed. Map to `java.time.LocalDateTime` for modern date/time handling. |
| `ShipperID` | INT (Optional) | Establishes a relationship with `Shippers.ShipperID`. Essential for data integrity and joins. |