| 1 | Parent |
| A code to indicate a parent relationship. |
| 2 | Child |
| A code to indicate a child relationship. |
| 3 | Peer, internal |
| A code to indicate an internal peer relationship. |
| 4 | Peer, external |
| A code to indicate an external peer relationship. |
| 5 | Finish to start constraint |
| A code to indicate a finish to start constraint relationship. |
| 6 | Start to start constraint |
| A code to indicate a start to start constraint relationship. |
| 7 | Finish to finish constraint |
| A code to indicate a finish to finish constraint relationship. |
| 8 | Start to finish constraint |
| A code to indicate a start to finish constraint relationship. |
| 9 |
| Owner |
| A code to indicate an owner relationship. |
|
| 10 |
| Contact |
| A code to indicate a contact relationship. |
|
| 11 |
| Spouse |
| A code to indicate a spouse relationship. |
|
| 12 |
| Sibling |
| A code to indicate the relationship between brothers and/or sisters. |
|
| 13 |
| Father |
| A code to indicate a father relationship. |
|
| 14 |
| Mother |
| A code to indicate a mother relationship. |
|
| 15 |
| Neighbour |
| A code to indicate a neighbour relationship. |
|
| 16 |
| Friend |
| A code to indicate a friend relationship. |
|
| 17 |
| Guardian |
| A code to indicate a guardian relationship. |
