> ## Documentation Index
> Fetch the complete documentation index at: https://docs.davinci-app.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Relationships

## Description

Objects in the model have defined relationships with each other that establish an explicit knowledge graph of the system being modeled. These relationships are either unidirectional (`in` and `out`) or bidirectional (`inout`) and can be traversed by the user while exploring the model. A summary of the existing relationships in Davinci are dicussed below:

<Note>Relationships must be given a Relationship Type when created. Select the Relationship Type, then the Relationship Object when creating a new Relationship</Note>

### Base Relationships

| Property     | Description                                                                                                                                            |
| ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `Uses`       | Indicates that one element makes use of another within the model. Can be `in` and `out`.                                                               |
| `Reference`  | Denotes that a reference points to another element in the model. Is `out` from the reference object and `in` to its target.                            |
| `Performs`   | Represents that a part or entity is responsible for performing a specific action. Is `out` from the part and `in` to the action.                       |
| `Connect`    | Defines a connection between interfaces or ports. Is `inout`.                                                                                          |
| `Realized`   | Indicates that the object realizes some intent, design, or function of another object. Can be `in` and `out`.                                          |
| `Subject`    | Defines the subject of a requirement, linking it to relevant parts, actions, or entities. Is `out` from the requirement and `in` to the target object. |
| `Mitigation` | Indicates that one element mitigates a risk, issue, or other problem related to another element. Can be `in` and `out`.                                |
| `Source`     | Indicates the source or origin of the object or its intent. Can be `in` and `out`.                                                                     |
| `Impact`     | Represents the impact that one element has on another. Can be `in` and `out`.                                                                          |
| `Dependency` | Indicates that one element depends on another. Can be `in` and `out`.                                                                                  |
| `Resource`   | Indicates that one element uses a resource. Can be `in` and `out`.                                                                                     |
| `Validation` | Indicates that the element is validated by another element. Is `out` from the constraint and `in` to the target.                                       |
| `Transition` | Indicates a transition between states. Is `out` from one state and `in` to another state.                                                              |
| `Result`     | Indicates a result of one object occurring as a consequence of another object. Can be `in` and `out`.                                                  |

### Standard Custom Relationships

New projects always start with set of base custom relationships. You can choose to remove these from the [project settings view](/user-guide/project-settings/relationship-settings).

<Note>All of the following are defined as `inout`.</Note>

| Property          | Description                                               |
| ----------------- | --------------------------------------------------------- |
| `Data`            | Represents the exchange of data between parts.            |
| `Power`           | Indicates a power connection between parts.               |
| `Mechanical`      | Denotes a mechanical connection between parts.            |
| `Optical`         | Represents an optical link between parts.                 |
| `Chemical`        | Describes a chemical interaction between parts.           |
| `Electromagnetic` | Represents an electromagnetic relationship between parts. |
| `Thermal`         | Indicates a thermal exchange between parts.               |
| `Fluid`           | Indicates a fluid connection between parts.               |