Changes

|Prepares Schedules the execution of the supplied {{Code|$query}} string for asynchronous execution and returns a query id. The query will be queued as described in the article on [[Transaction Management]], and the result will optionally be cached in main-memory until it is fetched via [[#jobs:result|jobs:result]], or until {{Option|CACHETIMEOUT}} is exceeded. Queries may be updating.<br/>Variables and context items can be declared via {{Code|$bindings}} (see [[XQuery Module#xquery:eval|xquery:eval]] for more details). <br/>The {{Code|$options}} parameter contains evaluation options:* {{Code|cache}}: indicates if the query result will be cached or ignored (default: <code>truefalse</code>):** The result will be cached in main-memory until it is fetched via [[#jobs:result|jobs:result]], or until {{Option|CACHETIMEOUT}} is exceeded. ** If the query raises an error, it will be cached instead.** If the result will not be cached, the query id will immediately be discarded after query execution.* {{Code|start}}: a dayTimeDuration, time or dateTime can be specified to delay the execution of the query:** If a dayTimeDuration is specified, the query will be queued after the specified duration has passed. Examples for valid values are: <code>P1D</code> (1 day), <code>PT5M</code> (5 minutes), <code>PT0.1S</code> (100 ms). An error will be raised if a negative value is specified.** If a time is specified, the query will be queued at this time. Examples for valid times are: <code>02:00:00</code> (2am), <code>12:00:00</code> (noon). If the time lies in the past, toothe query will be executed next day.** If a dateTime is specified, the query will be queued at this date. Examples for valid values are: <code>2018-12-31T23:59:59</code> (New Year's Eve 2018, close to midnight). An error will be raised if the specified time lies in the past.* {{Code|interval}}: a dayTimeDuration string can be specified to execute the query periodically. An error is raised if the specified interval is less than one second (<code>PT1S</code>).

|{{Error|overflow|#Errors}} Too many queries or query results are queued. {{Option|CACHETIMEOUT}} can be decreased if the default setting is too restrictive.<br/>{{Error|range|#Errors}} A specified time or duration is out of range.