barcode vb.net 2010 Analytic Databases and Dimensional Design 13 in Software

Drawer Denso QR Bar Code in Software Analytic Databases and Dimensional Design 13

1 Analytic Databases and Dimensional Design 13
Reading QR Code In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
QR Code 2d Barcode Generation In None
Using Barcode maker for Software Control to generate, create Quick Response Code image in Software applications.
important feature of the star schema: how it is actually used. Understanding the basic usage pattern of the star schema allows the dimensional designer to make intelligent choices.
Read QR Code 2d Barcode In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
Paint QR Code In Visual C#.NET
Using Barcode generator for .NET Control to generate, create Quick Response Code image in VS .NET applications.
Querying Facts
Paint QR In Visual Studio .NET
Using Barcode generator for ASP.NET Control to generate, create QR Code JIS X 0510 image in ASP.NET applications.
Quick Response Code Creator In .NET
Using Barcode creator for .NET Control to generate, create QR Code ISO/IEC18004 image in Visual Studio .NET applications.
Most queries against a star schema follow a consistent pattern. One or more facts are requested, along with the dimensional attributes that provide the desired context. The facts will be summarized in accordance with the dimensions present in the query. Dimension values are also used to limit the scope of the query, serving as the basis for filters or constraints on the data to be fetched and aggregated. A properly configured relational database is well equipped to respond to such a query, which is issued using Structured Query Language (SQL). Suppose that someone has asked to see a report showing order dollars by product category and product name during the month of January 2009. The orders star schema from Figure 1-5 can provide this information, even though order dollars is stored at a lower level of detail. The SQL query in Figure 1-6 produces the required results, summarizing tens of thousands of fact table rows. The SELECT clause of the query indicates the dimensions that should appear in the query results (category and product), the fact that is requested (order dollars), and the manner in which it will be aggregated (through the SQL Sum() operation). The FROm clause specifies the star schema tables that are involved in the query. The WHERE clause serves two purposes. First, it filters the query results based on the values of specific dimension columns (month and year). It also specifies the join relationships between tables in the query. In terms of processing time, joins are among the most expensive operations the database must perform; notice that in the case of a star schema, dimension attributes are always a maximum of one join away from facts. The GROuP BY clause specifies the context to which the fact will be aggregated by the relational database; the ORDER BY clause uses dimensions to specify how the results will be sorted. For readers new to dimensional design, there are two key insights to take away. First, the star schema can be used in this manner with any combination of facts and dimensions. This permits the star to answer questions that may not have been posed during the design process. Although facts are stored at a specific level of detail, they can be rolled up or summarized at various levels of detail. The reporting possibilities increase dramatically as the richness of the dimension tables is increased. Second, note that the ability to report facts is primarily limited by the level of detail at which they are stored. While it is possible to aggregate the detailed fact table rows in accordance with any set of dimensions, it is not possible to produce a lower level of detail. If a fact table stores daily totals, for example, it cannot be used to look at an individual order. The importance of this limitation depends in part on your data warehouse architecture, as you will see in the next chapter. Of course, star schema queries can get much more complex than this example. Queries may build on this template in a number of ways. A very important type of report requires that we merge query results sets from more than one star. These drill-across reports will be discussed in 4, A Fact Table for Each Process. Some reports add subqueries to the mix, enhancing the selection of relevant facts, as discussed in 16, Design and Business Intelligence. Another type of report necessitates the performance of set operations with the results of more than one query, as discussed in 12. It is also possible that facts may be aggregated in other ways, perhaps by averaging them or simply counting them.
Drawing QR Code 2d Barcode In VB.NET
Using Barcode creation for .NET Control to generate, create QR Code 2d barcode image in Visual Studio .NET applications.
Make UPC Symbol In None
Using Barcode maker for Software Control to generate, create GTIN - 12 image in Software applications.
Barcode Drawer In None
Using Barcode printer for Software Control to generate, create barcode image in Software applications.
Make Code 3/9 In None
Using Barcode creator for Software Control to generate, create Code 3/9 image in Software applications.
Generating EAN-13 Supplement 5 In None
Using Barcode drawer for Software Control to generate, create EAN-13 Supplement 5 image in Software applications.
Code 128A Maker In None
Using Barcode generation for Software Control to generate, create Code 128B image in Software applications.
ITF Creation In None
Using Barcode drawer for Software Control to generate, create Uniform Symbology Specification ITF image in Software applications.
Create EAN-13 In None
Using Barcode drawer for Word Control to generate, create EAN-13 Supplement 5 image in Microsoft Word applications.
Generating Barcode In Visual Studio .NET
Using Barcode creator for Reporting Service Control to generate, create bar code image in Reporting Service applications.
UCC.EAN - 128 Encoder In Java
Using Barcode generation for Java Control to generate, create GS1 128 image in Java applications.
USS Code 39 Maker In None
Using Barcode maker for Online Control to generate, create Code 3/9 image in Online applications.
Generating Bar Code In Objective-C
Using Barcode generation for iPad Control to generate, create barcode image in iPad applications.
Decoding USS Code 39 In VB.NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in .NET applications.
Bar Code Creator In Java
Using Barcode generation for Android Control to generate, create barcode image in Android applications.
Copyright © OnBarcode.com . All rights reserved.