MarkLogic 10 Product Documentationes:optional
es:optional( $instance as map:map, $key-name as xs:string, $key-value as item()? ) as map:map
Summary
This function is deprecated and will not be supported in MarkLogic 11.
Add a key-value pair to a map, if the value exists, and return
the modified input map. This function is meant for use in code
generated by Entity Services.
| Parameters | |
|---|---|
| instance | A map:map representation of an entity instance. |
| key-name | A key name. |
| key-value | The value to which to set the key, if the value exists. |
Usage Notes
This function is included for use within the modules that Entity Services
generates for manipulating instance data. It is identical to
map:with
except map:with
inserts a key with a null value in the case of an empty value. This
function leaves the map unmodified if there is no value.
This function returns the original instance, with
the key-value pair added.
See Also
- Creating and Managing Models in the Entity Services Developer's Guide.
Example
xquery version "1.0-ml";
import module namespace es = "http://marklogic.com/entity-services"
at "/MarkLogic/entity-services/entity-services.xqy";
json:object() =>es:optional("a", "value")
=>es:optional("missing", ())
(: returns an object with one key/value pair, {"a", "value"} :)