Constraint Specifications

You specify constraints and validation tests in Majic using the object definition metalanguage.

Note: For information, see the Technical Reference Guide.

Constraints defined in Majic closely resemble an SQL WHERE clause, with the following exceptions:

Attribute names in the constraint are object attribute names, not the database attribute name from the schema.
You can refer to the value of an attribute in the contact record for the logged‑in user with a name of the following form, where att_name is the Majic name of the desired attribute:
```
@root.att_name
```
For example, specifying @root.location refers to the location ID of the current contact.

You specify joins with a specification of the following form, where foreign-key is the Majic name of the SREL attribute in the table for which you are writing the data partition constraint, and attribute-in-referenced-table is the Majic name of the attribute in the table being joined:
```
foreign-key.attribute-in-referenced-table
```
For example, to refer to the maintenance vendor of the asset associated with an incident report, specify the following:
```
resource.vendor_repair
```
This specification is recursive. For example, you could refer to the name of the vendor with the following:
```
resource.vendor_repair.name
```

The following table contains examples of valid constraints to use for the Change_Request table, used to store change order information:

Constraint Type

Code and Description

View

assignee.organization = @root.organization

Specifies the user can only view change orders where the assignee’s organization is the same as the user’s organization.

Pre-Update

requestor = @root.id

Specifies the user can only update the change orders where he is the caller or requester.

However, you cannot write a constraint that uses joins on both sides of the expression, as shown in the following example:

assignee.org = requestor.org