There are many times when universe development task is big and it’s not possible to dingle person to develop the universe in stipulated time. To cater this need Business Objects has provided the facility to divide the universe design task amongst several designers and then integrate the work in single universe using universe linking method.
What is Universe Linking?
Linked universe are universes which share common component such as objects, classes and joins. When two universes are linked the one universe is called as core universe. It’s the main universe which contains common components where other universe is called as derived universe. Changes made to core universe are automatically propagated to derived universe.
Uses and advantages of universe linking.
- When you have to develop multiple universes but there are some common components across these universes in that you can create a core universe of common components and link it to other universes.
- Linking of Universe enables to distribute the universe designing task amongst other developers.
- It’s also helps to follow the code-reusability practices.
- If there are any changes to common objects. It needs to be done only in core universe. It gets propagated to all derived universes.
- Linking of universes help in universe maintenance.
Universe Linking Strategies.
Core Strategy: This strategy is used when you need to develop a universe for different functions. In such case you can create multiple universes for each function and the link all universes in single universe. This strategy allows us to create a common object only once and also help to split the universe design task amongst developers.
Master Strategy: Suppose you have a requirement to create clone of existing universe. You can achieve this by creating another copy of existing universe however this will increase maintenance as you would need to maintain two universes now. To avoid that you can use master linking strategy. In which existing universe is linked to new blank universe so it creates a copy of existing universe with different CUID and we need to maintain only one universe as core universe is linked.
Multiple Core Strategy: Now if you want divide the development task then you can follow this approach in which developers can develop their universe and at the link all universe in one universe.
Limitations and Restrictions of Linking Universes:
- Both the universes (core and derived) must use same connection and should connect to same database.
- Both the universe must be present in same repository in order to link.
- Only one level of linking is allowed you can create derived universe from another derived universe.
- Both universes should have unique object and classes. If there are duplicate objects/classes it will be renamed in core universe.
- Tables from two universes must be joined after linking in order to avoid Cartesian product.
- When core universe is linked in derived universe only classes, objects and tables are made available in derived universe. Context and LOV needs to be recreated in derived universe.
How to Link Universes?
To link universe make sure
- · Core universe is exported to repository
- · It’s open in designer.
- · Now open universe parameters from File->Parameters
- · Click on “Link” tab
- · Click on “Add Link”
- · Select the core universe to link.
- · Click OK
- · After this components from core universe will be available in derived universe and it will be grayed.
- · Now analyze the derived universe and create joins between tables added from core universe.
- · Create context/Alias wherever required.
- · Save and Export the derived universe.
Using Include to import one universe into another
In linking universe contents are not copied to derived universe and one cannot edit the core universe components in derived. However sometimes one need to merge two universe into one. For this purpose one can use “Include” universe approach instead of linking. When universe are included components of one universe are copied into another.
Difference between Linking and Including Universes
Including and Linking decision needs to be taken based on your own need following are the points which may help.
Linking.
- · Core universe structure is created once and used in many derived universe.
- · Only one copy of components from core universe exists in repository.
- · Changes needs to done only to core universe and it gets propagated to all derived universe.
- · Linking universe needs both the universe to be present in repository.
- · Only one level of linking is allowed.
- · Context and LOV needs to recreate in derived universe.
- · Both the universe must use same connection and connect to same database
Including
- · It’s the easiest and fastest way to copy universe into another.
- · Context needs to redefine after including.
- · Changes are not propagated from core to derived universe.
- · Both the universe must exist in repository like in linking.
- · One can easily maintain one universe rather than multiple universe o maintenance becomes bit easy.
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