# ask-ai

Andrea Montes

03/12/2024, 3:15 PM
@Scout how does materialize api work?


03/12/2024, 3:15 PM
The materialization API in Dagster is a way to define how data assets are produced and tracked within the system. Materialization is a term used to describe the process of persisting a data asset as a result of a computation. In Dagster, you can define materializations using the
decorator, which indicates that a function produces an asset. Here's a high-level overview of how the materialize API works: 1. Defining Assets: You use the
decorator to define a function that computes an asset. By default, the name of the function is used as the name of the asset. 2. Materialization Events: When an asset is computed, you can yield
events to record metadata about the asset in Dagster's asset catalog. This metadata can include information like the location of the asset, a description of the asset, or any custom metadata you wish to include. 3. Asset Catalog: Dagster includes a built-in asset catalog that indexes all the assets produced by your pipelines. This catalog allows you to track the history of an asset over time, watch for trends, and explore all the assets produced by your pipelines. 4. Materializing Assets: To materialize an asset, you can trigger its computation manually through the Dagster UI by clicking the "Materialize" button, or you can set up schedules, sensors, or auto-materialization policies to materialize assets automatically based on certain conditions or events. 5. Auto-Materialization: Dagster also supports auto-materialization policies that can automatically materialize an asset or a selection of assets when specified criteria are met, such as upstream changes. This is an experimental API that allows for a declarative approach to asset materialization. 6. Asset Sensors: Asset sensors can start a job when a materialization occurs for a specific asset or selection of assets, allowing you to trigger jobs in response to asset materializations. The materialize API is a flexible and powerful feature of Dagster that integrates with the rest of the system to provide self-service observability and automation for your data assets. It simplifies data orchestration by enhancing your existing code with an understanding that your code produces data assets, and it provides a structured way to track and manage those assets over time.