PersistentObject

PersistentObject["name",loc]

represents a persistent object stored at persistence location loc.

Details

  • PersistentObject["name",loc]["meta"]=val sets the metadata element "meta" to val.
  • The following metadata elements can be given:
  • "Value"Nullthe value of the persistent object itself
    "HeldValue"Hold[Null]the value wrapped in Hold
    "MergingFunction"Automaticthe default merging function to use
    "ValuePreprocessingFunction"Identitythe function applied to new values to be assigned
    "ModificationDate"Nonetime stamp of last modification
    "ExpirationDate"Nonetime after which data is no longer used
    "Creator"$UserNameuser who last modified the object
  • PersistentObject["name",loc][All] gives the association of all metadata.
  • DeleteObject[PersistentObject[]] removes a persistent object from the specified location.
  • A persistence location is given as PersistenceLocation["type"] or "type".

Examples

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Basic Examples  (2)

Create a persistent object by assigning it a value:

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Give all metadata of the object:

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Give a specific meta element:

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Remove a persistent object:

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Remove all persistent objects with a given key on $ContextPath:

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Scope  (1)

Properties & Relations  (3)

Possible Issues  (1)

See Also

PersistentValue  PersistenceLocation  PersistentObjects  LocalObject  CloudObject  ResourceObject  Databin

Introduced in 2017
(11.1)