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Platform Attributes

In addition to the properties that can be expressed by modeling native and derived attributes, each object in Livebase is associated with a set of metadata, related to its corresponding record in the relational database (including, for example, the unique identifier or creation date).

In the engine model, you can choose to make this information explicit on classes by enabling one or more platform attributes, characterized by the reserved prefix __.

The following platform attributes are available:

  • __id: a unique identifier;
  • __createdby: the user who created the object;
  • __createdon: the date and time the object was created;
  • __lastmodifiedby: the user who made the last modification;
  • __lastmodifiedon: the date and time of the last modification;
  • __ownedby: the user who owns the object;
  • __ownedon: the date and time when the user acquired ownership of the object.

Platform attributes

A class to which all available platform attributes have been added

Platform attributes thus enabled, as for all attributes, can be referenced in Livebase expressions to define other derived attributes, or to define filters or Class warnings at the Application Schema level.

Platform attributes are automatically valued by Livebase and are therefore read-only information. Therefore, it is not possible to perform some of the operations normally allowed with native attributes:

Enable a platform attribute #

Right-click on a class to open its Class menu and select New platform attribute; choose the platform attribute from the list.

Enable a platform attribute