The Gold Layer is the business-level data representation, structured to support analytical and reporting use cases. It consists of dimension tables and fact tables for specific business metrics.

**Purpose:** Stores customer details enriched with demographic and geographic data.

| Column Name | Data Type | Description |

|--------------------|---------------|-----------------------------------------------------------------------------|

| `customer_key` | INT | Surrogate key uniquely identifying each customer record in the dimension table. |

| `customer_id` | INT | Unique numerical identifier assigned to each customer. |

| `customer_number` | NVARCHAR(50) | Alphanumeric identifier representing the customer, used for tracking and referencing. |

| `first_name` | NVARCHAR(50) | The customer's first name, as recorded in the system. |

| `last_name` | NVARCHAR(50) | The customer's last name or family name. |

| `country` | NVARCHAR(50) | The country of residence for the customer (e.g., 'Australia'). |

| `marital_status` | NVARCHAR(50) | The marital status of the customer (e.g., 'Married', 'Single'). |

| `gender` | NVARCHAR(50) | The gender of the customer (e.g., 'Male', 'Female', 'n/a'). |

| `birthdate` | DATE | The date of birth of the customer, formatted as YYYY-MM-DD (e.g., 1971-10-06). |

| `create_date` | DATE | The date and time when the customer record was created in the system. |

**Purpose:** Provides information about the products and their attributes.

| Column Name | Data Type | Description |

|---------------------------|---------------|-----------------------------------------------------------------------------|

| `product_key` | INT | Surrogate key uniquely identifying each product record in the product dimension table. |

| `product_id` | INT | A unique identifier assigned to the product for internal tracking and referencing. |

| `product_number` | NVARCHAR(50) | A structured alphanumeric code representing the product, often used for categorization or inventory. |

| `product_name` | NVARCHAR(50) | Descriptive name of the product, including key details such as type, color, and size. |

| `category_id` | NVARCHAR(50) | A unique identifier for the product's category, linking to its high-level classification. |

| `category` | NVARCHAR(50) | The broader classification of the product (e.g., Bikes, Components) to group related items. |

| `subcategory` | NVARCHAR(50) | A more detailed classification of the product within the category, such as product type. |

| `maintenance_required` | NVARCHAR(50) | Indicates whether the product requires maintenance (e.g., 'Yes', 'No'). |

| `cost` | INT | The cost or base price of the product, measured in monetary units. |

| `product_line` | NVARCHAR(50) | The specific product line or series to which the product belongs (e.g., Road, Mountain). |

| `start_date` | DATE | The date when the product became available for sale or use. |

**Purpose:** Stores transactional sales data for analytical purposes.

| Column Name | Data Type | Description |

|---------------|----------------|-------------|

| order_number | NVARCHAR(50) | A unique alphanumeric identifier for each sales order (e.g., 'SO54496'). |

| product_key | INT | Surrogate key linking the order to the product dimension table. |

| customer_key | INT | Surrogate key linking the order to the customer dimension table. |

| order_date | DATE | The date when the order was placed. |

| shipping_date | DATE | The date when the order was shipped to the customer. |

| due_date | DATE | The date when the order payment was due. |

| sales_amount | INT | The total monetary value of the sale for the line item, in whole currency units (e.g., 25). |

| quantity | INT | The number of units of the product ordered for the line item (e.g., 1). |

| price | INT | The price per unit of the product for the line item, in whole currency units (e.g., 25). |