PATTERNS OF DATA MODELING- P46 pot

... the deletion of an Asset record could cause the deletion of the corresponding OwnedAsset. Then the deletion of an OwnedAsset could cause deletion of its RentedAssets. But deletion of a RentedAsset ... option Propagated PK of an entity comes from a relationship. • Awkward depen- dency between entities. A poor option Table 16.1 Summary of Approaches to Design Identity Note: I...

Ngày tải lên: 05/07/2014, 06:20

... Software Architecture: A System of Patterns. Chichester, United Kingdom: Wiley, 1996. [Chen-1976] PPS Chen. The entity-relationship model—toward a unified view of data. ACM Transac- tions on Database ... Vlissides. Design Patterns: El- ements of Reusable Object-Oriented Software. Boston, Massachusetts: Addison-Wesley, 1995. [Hay-1996] David C. Hay. Data Model Patterns: Conventions...

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... branch nodes. A Tree is a hierarchy of nodes and has one node as the root. A particular node may, or may not, be the root. You need not show Tree in a use of the tem- plate. A Node is either ... nodes each of which, in turn, can be a leaf node or a further branch node. Figure 2.18 adds the constraint that a tree cannot have any cycles. (See Section 2.2.1 for an explanation of cycles.)...

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... a person can be manager of one group and an acting manager of another group. The same person may be an individual contributor and a manager during different portions of a Figure 2.36 Tree changing ... differ from that of its various positions. A Tree is a hierarchy of nodes and has one node as the root. A Node is a position within a Tree. An Entity is something with identity and da...

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... (directed graph) is a set of nodes and a set of directed edges that connect nodes. (Note: in a directed graph all nodes do not have to be connected.) You need not show DG in a use of the template. A ... represented via the coupling between nodes. The populated tables use different data than Figure 3.1 because the premise of the template is a tree that is generalized to having multip...

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... published de- scription of air travel between two airports. The frequency indicates the days of the week for which the PublishedFlight applies. A PublishedFlight consists of a sequence of Published- FlightLegs ... Directed Graph Template 49 A DG (directed graph) is a set of nodes and a set of directed edges that connect nodes. You need not show DG in a use of the template. A Nod...

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... background for data and a light gray for metadata. The item description template is useful if you cannot fully describe data as software is being developed. The template lets you enter data and its ... Item description: UML template. Use when the same model relates data and metadata. ItemDescription Item Characterization Metadata Data Flexibility General purpose Specific Volatility...

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... characterization of a common software flaw. The antipatterns in Table 9.1 simplify reading but compromise the ability of database structure to enforce quality. These antipatterns are often acceptable for data ... (FK) accountEquivalenceID AccountEquivalence tangibleActorID TangibleActor . . . 118 Chapter 9 / Non -Data- Warehouse Antipatterns into a single dimension entity. For example,...

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... 10.17, Figure 10.18). The notion of an event often appears in application models. An EventType is a general category of Events. This archetype involves data and metadata and uses the shading convention ... the definition of events by their similarities and differences using generalization. There is also a simple model of cause and effect. A group of causes might lead to a group o...

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... that the combination of fields will be unique. I strongly encourage the use of candidate keys. After all, the purpose of a database is not only to store data but also to assure data s quality. When ... to find data in a database or the database is compromised. 11.1 Intrinsic Identity Intrinsic identity is the ability to find data with fields that have meaning. Starting from out-...

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