# Define & reuse global SQL definitions

> This document describes how to use AML Constant to define SQL definitions globally and reuse them in data models

Let's say that you define a dimension called `price_category` using SQL in one data model. As you work on other data models, you notice that the same SQL definition is also needed. 

With [AML Constant](/reference/aml/constant), you can declare the SQL definition as a const within a separate AML file, and then reuse it in any relevant data models in your AML project. This will help reduce code duplication, and eliminate the need to update multiple piece of code.

```aml

// Define a SQL definition as const in a separate AML file
// highlight-next-line
// In reused_sql_defs.aml
const price_category_sql = @sql select 
	case when price >= 3000 then 'Expensive' 
	else 'Cheap' end as price_category;;

// highlight-next-line
// In order.model.aml
DataModel order {
	// ...
	table_name: 'ecommerce_orders'
	data_source_name: 'ecommerce'
	dimension price_category {
		label: "Price Category"
		type: "text"
		hidden: false
		// highlight-next-line
		definition: price_category_sql
	}
}

// highlight-next-line
// In order_item.model.aml
DataModel order_item {
	// ...
	table_name: 'ecommerce_order_items'
	data_source_name: 'ecommerce'
	dimension price_category {
		label: "Price Category"
		type: "text"
		hidden: false
		// highlight-next-line
		definition: price_category_sql
	}
}
```