# Reference Sets

Two categories make up Snow Owl's Reference Set API:

1. **Reference Sets** category to get, search, create and modify reference sets
2. **Reference Set Members** category to get, search, create and modify reference set members

Basic operations like create, update, delete are supported for both category.

## Actions API

On top of the basic operations, reference sets and members support actions. Actions have an *action* property to specify which action to execute, the rest of the JSON properties will be used as body for the Action.

Supported reference set actions are:

1. **sync** - synchronize all members of a query type reference set by executing their query and comparing the results with the current members of their referenced target reference set

Supported reference set member actions are:

1. **create** - create a reference set member (uses the same body as POST /members)
2. **update** - update a reference set member (uses the same body as PUT /members)
3. **delete** - delete a reference set member
4. **sync** - synchronize a single member by executing the query and comparing the results with the current members of the referenced target reference set

For example the following will sync a query type reference set member's referenced component with the result of the reevaluated member's ESCG query

```
POST /members/:id/actions
{
  "commitComment": "Sync member's target reference set",
  "action": "sync"
}
```

## Bulk API

Members list of a single reference set can be modified by using the following bulk-like update endpoint:

```
PUT /:path/refsets/:id/members
```

Input

```
{
  "commitComment": "Updating members of my simple type reference set",
  "requests": [
      {
        "action": "create|update|delete|sync",
        "action-specific-props": ...
      }
  ]
}
```

The request body should contain the commitComment property and a request array. The request array must contain actions (see Actions API) that are enabled for the given set of reference set members. Member create actions can omit the *referenceSetId* parameter, those will use the one defined as path parameter in the URL. For example by using this endpoint you can create, update and delete members of a reference set at once in one single commit.