Directives

This is a reference of all the GraphQL directives that can be used to direct how data is generated with GraphGen. They are attached to an associated field, and modify and inform the way in which GraphGen will generate it.

@has(chance: Float!)

Used to indicate what the probability is that a record will have a related record. Only applicable to fields which represent relationships. The type of the field must be nullable.

options

• chance: A number between number 0 and 1 indicating the probability that a related record exists. [default:0.5]

example

type Person {
  employer: Business @has(chance: 0.9)
}

@gen(with: String! args: [String|Float|Int|Boolean])

Every field has a generation method. This directive explicitly sets the name of that method.

options

• with: a string identifying the generation method. It can be any unique string
• args: arguments that will be passed to the generation method that is registerd with factory.

Examples

# use a generation method
type Person {
  name: String! @gen("@human/name")
}

# pass arguments to the generation method
# the meaning of the arguments are up to the method itself
type Person {
  name: String! @gen("names", args: ["type", "human"])
}

Notes

If an explicit generation method is not specified, it will default to the typename concatenated with the field name. E.g. Person.name

@computed

Mark a field as being derived from the record data and not generated. The implemenation of the computed field must be provided to createGraphgen().

Examples

type Person {
  firstName: String!
  lastName: String!
  fullName: String! @computed

@size(mean: Int, min: Int, max: Int, standardDeviation: Int)

Describe the noraml distribution that governs how many related records will be generated. Only applicable to list fields.

• mean: the average number of related records. [default:5]
• standardDeviation: the standard deviation of the number of related records. A small number will mean that the size clusters close to the mean, but a larger value causes samples to be scattered farther from the average. [default:1]
• min: the number of related records will always be greater than this number. Must be greater than or equal to zero. [default:0]
• max: the number of related records will never be greater than this number. [default:Infinity]

Examples

type Person {
  employees: [Person] @size(mean: 100, standardDeviation: 10, min: 1)
}

@inverse(of: String!)

Marks a relationship as being the other side of another relationship. The other side of the relationship is named with the concatenation of the typename and fieldname. This allows GraphGen to generate related records but still maintain referential integrity. It must reference a relationship that existis by its fully qualified name. This can be attached to both normal and list fields, so long as the type is a record type.

• of: The name of the inverse relationship in typename.fieldname format. E.g. Person.employer

Examples

type Person {
  employer: Business! @inverse(of: "Business.employees")
}

type Busines {
  employees: [Person]
}

@affinity(of: Float!)

A number between 0 and 1 indicating the probability that any two records of a given type are related via the relationship expressed by the associated field. When generating related records, graphgen will use this probability to determine whether to create a new record, or to point a relationship to an existing record. Specifically, as the population of related types increases, you begin to create fewer and fewer new records in order to satisfy the affinity constraint.

An affinity of zero means that a new record will always be created, whereas an affinity of one indicates that an an existing record will always be used except in the event that there is not yet one existing record already.

Use affinity to make graph generation converge rather than exploding into infinity.

• of: probability that two records of the given type are related. Must a number between 0 and 1.

Examples

# the probability that any two people are friesds is 5%
type Person {
  friends: [Person] @affinity(of: 0.05)
}