SMK / Configuration / Layers / Query / Parameter

Select Unique Layer Query Parameter

Use a select parameter to provide a value to the query predicate that comes from the user picking a value from a drop-down list. The drop-down list is populated dynamically from the layer by finding all unique values for "uniqueAttribute" property. If the request to populate the drop-down fails, the drop-down field changes to an input field. The "choices" property may be used as well to provide a fall-back.

Note

DO NOT use this parameter type if you know the number of unique values will be more than a few hundred.

A parameter object is defined with these properties. Click on a property name for more information:

{
    "type":            "select-unique",
    "id":              null,
    "title":           null,
    "value":           null,
    "choices":         null,
    "uniqueAttribute": null
}

Type Property

"type": String

The type of parameter object.

Must be one of these values: "constant", "input", "select", or "select-unique".

Id Property

"id": String

The unique identifier for the parameter. This MUST be unique within the layer query parameter list. Conventionally it is all lowercase with - separating words.

Title Property

"title": String

The title to show in query form for this parameter.

Value Property

"value": String

The default value for the parameter. If not provided, the user MUST provide a value to execute the query.

Choices Property

"choices": Array

An array of { title, value } objects to populate a drop-down list. The title is optional.

UniqueAttribute Property

"uniqueAttribute": String

The name of the attribute on the layer that will be queried to find all unique values.