# Business Rules

In order to define a Business Rule, you need to define both a `Selection` and one or multiple `Rule(s)`. The `Selection` defines which data you want to measure and the `Rule` defines the rule that you want to apply to the data.

The `Selection` is a query that results in a dataset with the columns that you need. The `Rule` is a SQL query that is applied to the result of the `Selection`. the `Rule` should result in a single column where each row contains a boolean (True/False) value. When the value is `True`, the data meets the requirement of the rule. When the value is `False`, the data does not meet the requirement of the rule.

```{mermaid}
flowchart LR;
  business_rule --> selection;
  selection --> rules;
```

## YAML Example

```yaml
# Example of a Business Rule in YAML format
name: "Each policy should have a single person"
selection_query: "SELECT * FROM policy LEFT JOIN person ON policy.person_id = person.id"
custom_properties: 
- application: policy_timeline
rules:
- rule: "Each policy should have a person"
  query: "person.id IS NOT NULL"
- rule: "Each policy should only contain a single person"
  query: "ROW_NUMBER() OVER (PARTITION BY policy.id) = 1"
```

## End Points
At the following location the API references can be found: [Athora Data Quality End Point Docs](https://app-dq-dev-01.azurewebsites.net/docs#/). For Business Rules, the following end points can be used:
```
Manage:
/business_rules #POST for adding a new selection
/business_rules/{id} #PUT for changing an existing selection

Find (GET):
/business_rules #For returning all selections
/business_rules/{id} #For finding a specific selection
```

This will result in a table that shows which policies do not meet the requirement of having a single person.

# Selections
As preparations for Business Rules, a dataset can be predefined with the Selections End Points. This selection can be referenced in the Business Rule(s).

## End Points
At the following location the API references can be found: https://app-dq-dev-01.azurewebsites.net/docs#/. For Selections, the following end points can be used:
```
Manage:
/selections #POST for adding a new selection
/selections/{id} #PUT for changing an existing selection

Find (GET):
/selections #For returning all selections
/selections/{id} #For finding a specific selection
/selections/find_one #To find specific selections without pagination
/selections/find  #To find specific selection with pagination
```

## Custom Properties
Predefined tags can be given to multiple parts within the API. These tags can be used to e.g. group or catagorize toSelections and Business Rules.

### End Points
At the following location the API references can be found: https://app-dq-dev-01.azurewebsites.net/docs#/. For Custom Properties, the following end points can be used:
```
Manage:
/custom_properties #POST for adding a new selection
/custom_properties/{id} #PUT for changing an existing selection

Find (GET):
/custom_properties #For returning all selections
/custom_properties/{id} #For finding a specific selection
/custom_properties/find_one #To find specific selections without pagination
/custom_properties/find  #To find specific selection with pagination
```