PATTERNS OF DATA MODELING- P22 pps

... various combinations of dimensions. (Section 6.1.5 discusses the store sales example.) Such queries can involve massive amounts of data, so performance is always a concern. Data warehouses use ... subset of data for store sales and is covered further in the next section. In practice there are a modest number of dimension re- cords (tens or hundreds per table) and a large number...

Ngày tải lên: 05/07/2014, 06:20

... time. Records the history of a tree. This template permits storing of the past, present, and future content of trees. • Degenerate node and edge. Use when there is data for the parent–child grouping. Table ... tree. References [Fowler-1997] Martin Fowler. Analysis Patterns: Reusable Object Models. Boston, Massachusetts: Addison-Wesley, 1997. Figure 2.46 Excerpt of data model for...

Ngày tải lên: 05/07/2014, 06:20

... chief information officer may report to both the chief operating officer and chief financial officer. The model can store the current reporting structure, report- ing structures of the past, and ... unimportant and the history of a directed graph must be recorded. • Node and edge directed graph changing over time. Use when there is data for edges and the history of a directed graph mu...

Ngày tải lên: 05/07/2014, 06:20

... Template Bibliographic Notes Page 89 of [Hay-1996] has an example of projects that involve the node and edge directed graph. References [Hay-1996] David C. Hay. Data Model Patterns: Conventions of Thought. New York, ... An undirected graph is a set of nodes and a set of edges. Each edge connects two nodes (which may be the same). The nodes of an undirected graph can have any nu...

Ngày tải lên: 05/07/2014, 06:20

... characterization of a common software flaw. As you construct models, you should be alert for antipatterns and correct them. Table 8.1 summarizes universal anti- patterns antipatterns to always ... 8.1 Summary of Universal Antipatterns 110 Chapter 8 / Universal Antipatterns for improving software quality. [Laplante-2006] builds on [Brown-1998] and adds further management antipatterns as ....

Ngày tải lên: 05/07/2014, 06:20

... the owner as well as money in lieu of partial shares. A computing transaction (often involving a database) is a group of commands that is treated as a unit of work. All commands must be completed ... 10.2). Ven- dors often have special data to collect, such as supply data, credit information, and order lead time. You could use softcoding (see Chapter 13) to capture vendor data, but...

Ngày tải lên: 05/07/2014, 06:20

... nuances of patterns. Chapter 16 elaborates this use of two modeling notations and presents an overview of my approach to the database design process. I begin constructing a model with the UML data structure ... VI Relational Database Design Chapter 16 Relational Database Design 205 This book is about patterns and patterns are described via models. I have presented two no- tation...

Ngày tải lên: 05/07/2014, 06:20

... accumulating the history of past data. A data warehouse puts data in one database and stores data in a common format for reporting purposes. database a permanent, self-descriptive store of data that is contained ... the identity of occurrences of a critical concept and unifies its data across an organization’s applications. mathematical template See template. metadata data...

Ngày tải lên: 05/07/2014, 06:20

... granularity, than does the percentage of active data. For track images, percentages in the range of 10 - 20 percent of active data were found to be persistent in a window of 24 hours; for files, the ... migration of unused data after one week or more would have a good chance of being acceptable from the standpoint of application performance. Figure 7.14 presents the av...

Ngày tải lên: 03/07/2014, 08:20

Ngày tải lên: 05/07/2014, 06:20