PATTERNS OF DATA MODELING- P20 doc

... the pre- vious section, a shading convention differentiates metadata from data. Light gray indicates metadata and white indicates data. Figure 5.8 Item description: Report model. ReportDefinition name ReportExecution creationDatetime Person name 1 1 * * Metadata Data creator ** * ** * 11 0 ... model. ReportDefinition name ReportExecution creationDatetime Person name 1 1 * * Metadata Dat...

Ngày tải lên: 05/07/2014, 06:20

... Individual- Contributors necessitating the use of subtypes. For example, only Managers can be in charge of Departments. Many years ago, the original Microsoft PC-DOS file structure was a hierarchy. ... explains.) In Figure 2.26 a File may be a DataFile or a DirectoryFile. Directories contain multiple files, some or all of which may be subdirectories. The combination of a DirectoryFile...

Ngày tải lên: 05/07/2014, 06:20

... (FK) dimension1ID data Dimension1 dimension2ID data Dimension2 dimension3ID data Dimension3 dimension4ID data Dimension4 dimension6ID data Dimension6 dimension5ID data Dimension5 dimension7ID data ... Dimension7 dimension8ID data Dimension8 data 82 Chapter 5 / Item Description Template 5.3 Chapter Summary The item description template arises when a model re...

Ngày tải lên: 05/07/2014, 06:20

... data. An application may also have a database that developers populate apart from Eclipse. If you reverse engineer the database, the resulting model can appear to be incomplete. Ideally the database ... I was reverse engineering the database of a commercial product and was perplexed. The resulting model had many disconnected entity types with only a smattering of relationships. I could...

Ngày tải lên: 05/07/2014, 06:20

... and there is special data to collect for them, such as sales data, credit information, and discount schedules. You could use softcoding (see Chapter 13) to capture customer data, but an alternative ... define a dis- tinct Customer entity type as shown here. 10.8 Document A Document is a physical or electronic representation of a body of information (Figure 10.15, Figure 10.16). Figure...

Ngày tải lên: 05/07/2014, 06:20

... (FK) attributeID (FK) dataSourceID dataSourceName (AK1.1) DataSource overrideUOMID (FK) dataSourceID (FK) unitOfMeasureID unitOfMeasName (AK1.1) UnitOfMeasure defaultUnitOfMeasureID (FK) Figure 13.12 Softcoded ... This approach can be useful for a small amount of miscellaneous data, but is not suitable for large quantities. Figure 13.11 Softcoded values—add value metadata: IDEF1X model. en...

Ngày tải lên: 05/07/2014, 06:20

... areas. The generic diagram model provides a starting point for various kinds of diagrams such as data structure diagrams, data flow diagrams, state diagrams, and equipment flow diagrams. I have used ... that cause changes of state. State diagrams are often used for control and managing user interaction. They are also helpful for enforcing business policies and constraining data — th...

Ngày tải lên: 05/07/2014, 06:20

... else. “Lookup” data means metadata such as AccountType that is often implemented as a pick list in a user interface. Lookup tables have a small number of records (usually no more than tens of records) ... can be helpful for consolidating the data of an entity across generalization levels. Relational databases only partially support generalization. Relational databases cannot express...

Ngày tải lên: 05/07/2014, 06:20

... many columns each of which has a domain. A domain specifies a datatype, constraints on the data, and semantic meaning of the data. Thus the domain for UPC codes may store data as a string of digits with ... applications, to syn- chronize distributed databases, or to feed data warehouses. Triggers can also be helpful for keeping derived data consistent with its underlying base...

Ngày tải lên: 05/07/2014, 06:20

... of 1 month. THE FRACTAL STRUCTURE OF DATA REFERENCE The I/O trace data are used to explore reference patterns at the track image, cylinder image, and file levels of granularity. The SMF data ... levels of activity, but some level of activity continues to be observed. Storage performance practitioners rely implicitly on the presence of persis - tent patterns of ac...

Ngày tải lên: 03/07/2014, 08:20