Overview of Recipe Concepts¶
Ingredients are reusable fragments of SQL defined in SQLAlchemy. Ingredients can contribute to a SQL query’s select, group by, where clause or having clause. For convenience, we define Metric, Dimension, Filter, and Having classes which support common query patterns.
A Shelf is a container for holding named ingredients. Shelves can be defined with python code or via configuration. Shelves defined with configuration can be bound to a SQLAlchemy selectable.
By convention, all the ingredients on a Shelf should reference the same SQLAlchemy selectable.
A Recipe uses a Shelf. The Recipe picks dimensions, metrics, filters, and havings from the shelf. Dimensions and metrics can also be used to order results. While the Recipe can refer to items in the shelf by name, you can also supply raw Ingredient objects. Recipe uses a builder pattern to allow a recipe object to be modified.
A Recipe generates and runs a SQL query using SQLAlchemy. The query uses an Oven an abstraction on top of a SQLAlchemy connection. The query results are “enchanted” which adds additional properties to each result row. This allows ingredients to format or transform values with python code.
Recipe results can optionally be cached with the recipe_caching support library.
Extensions add to Recipe to change how SQL queries get built.
Recipe includes the following built-in extensions.
AutomaticFilter: Supports a configuration syntax for applying filters.
BlendRecipe: Allows data from different tables to be combined
CompareRecipe: Allows a secondary recipe against the same table to be combined.
Anonymize: Allows result data to be anonymized.