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Oberhohenberg
View over Deilingen to the Oberhohenberg
Elevation	1,011 m (3,317 ft)
Location
Oberhohenberg The location within Baden-Württemberg
Location	Baden-Württemberg, Germany
Range	Swabian Alb
Coordinates	48°09′50″N 8°45′38″ECoordinates: 48°09′50″N 8°45′38″E

The Oberhohenberg (1011 metres) is the second highest mountain of the Swabian Alb, only four metres lower than the Lemberg.

The ruins on its top derive from the year 1449, when the Castle Oberhohenberg together with the town of Hohenberg, located on the mountain's feet, were destroyed in a local feud.

 

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From Wikipedia, the free encyclopedia

Gammaridea is a suborder of small, shrimp-like crustaceans in the order Amphipoda. It contains about 7,275 (92%) of the 7,900 described species of amphipods, in approximately 1,000 genera, divided among around 125 families.^[1] Gammaridea includes almost all freshwater amphipods (such as Gammarus pulex), but most of its members are marine. The group may be paraphyletic,^[2] and a 2003 revision by Myers and Lowry moved several families from Gammaridea to join members of the former Caprellidea in a new suborder Corophiidea.^[1]

[edit]Systematics

From Wikipedia, the free encyclopedia

In computer science the concept of a Lossless-Join Decomposition is central in removing redundancy safely from databases while preserving the original data.

Contents [hide] 1 Lossless-join Decomposition 2 Example 3 Normal Forms 4 References

[edit]Lossless-join Decomposition

Can also be called Nonadditive. If you decompose a relation  into relations  and  you will guarantee a Lossless-Join if ⋈ = .

Let  be a relation schema.

Let  be a set of functional dependencies on .

Let  and  form a decomposition of .

The decomposition is a lossless-join decomposition of R if at least one of the following functional dependencies are in ⁺(where ⁺ stands for the closure for every attribute in ):^[1]

•  ∩  → 


•  ∩  → 

[edit]Example

• Let  be the relation schema, with , ,  and  attributes.


• Let  be the set of functional dependencies.


• Decomposition into  and  is lossless under  because  and  so .

[edit]Normal Forms

Decomposition into BCNF or 3NF must always be lossless.

[edit]References