ObjectRepository   Object Repository Overview When to Use Constant Form Object Data Types Examples

Object Repository Overview

An Object Repository is a Heap object containing zero or more bindings. Each binding is composed of an AIS Word data value and followed by an object reference key, allowing ObjectRepository values to be referenced and modified by object key. The ObjectRepository values are NOT stored in memory; instead, they are stored on disk. (Note: ObjectRepository key values are NOT restricted to Symbol objects, and may be references to any AIS heap object).

An Object Repository may be created with the following syntax:

(setq gor (new ObjectRepository: "myarchive.odb"))

When to Use

The ObjectRepository data type is used to save any object closure of any size and complexity.

Constant Form

The Object Repository Native data type is a container that holds a Word data value and an object reference key. It has no constanct form, but its contents may be modified or deleted using Object Repository Transactions.

Object Data Types

The ObjectRepository is a Heap Object or an Object Data Type. The Analytic Information Server Object Types are stored in the Heap and are managed by the Heap manager. The Analytic Information Server Heap manager supports object resizing, garbage collection, and anti-fragmentation algorithms so that the user may concentrate on the analysis and modeling of data rather than on memory management. Without exception, all of the Object types are identified by an object id. The object id identifies a block of memory, managed by the Lambda Information Server memory manager, in which the Object's data is stored.

The Analytic Information Server Heap Object and Native Data types can be saved and loaded to and from persistent (disk file) storage at any time. Containers with immediate data are saved on disk in fixed length records equal to the size of the container. Containers with Heap object references are saved in fixed length records, which are automatically expanded to include the contents of the Heap object, and any objects referenced by the Heap object, etc. This feature is called Object Closure Management and is automatic with every Analytic Information Server container database save.

Analytic Information Server containers may be loaded from any database repository record at any time. If the data in the record is immediate, the database load fills the container with the immediate data. If the data in the record is an object closure, the database load fills the container with a Heap object reference, and all of the objects in the record are loaded back into the Heap with the same referential relationships they had when they were saved in the repository.

The ObjectRepository object can be demonstrated by the following examples.