A dimension represents the amount of data you want to analyze, such as when you analyze a product's sales, you can choose to analyze it by category, or by region. Such a press. The analysis forms a dimension. The previous example can have two dimensions: type and region. In addition, each dimension can have sub-dimensions (called attributes), such as attributes t
What is a fact (fact) dimension relationshipDevelopers who have developed SSAS cube should know that there is a type of fact relationship in Cube's dimension usage, as shown in:The fact dimension relationship is just like the description in the red box above, which refers to a table even if the fact table is a dimension
VC Dimension (
Vapnik-Chervonenkis dimension) Is an important indicator of function set learning performance defined by statistical learning theory to study the speed and promotion of consistent convergence in the learning process. The traditional definition is: For an indicator function set, if H samples exist, functions in the function set can be separated by all possible forms of K power of 2, the functi
what it is.Now, I assume that through the above mentioned two articles about NF-HIPAC, you already know the multi-dimensional interval matching process, then we can be separated from the specific scene, it is abstracted into a general problem, first look at the abstract, in this diagram, I ignored the size of the interval, ignoring the rule of the permutation problem ( In the end I will return to this question):In this diagram, we see a lot of "?" , which means that we don't know what ruleset i
Original: SSAS Series--"02" Multidimensional Data (Dimension object)1. What is dimension? In mathematics, it is called a parameter, which is the number of independent space-time coordinates in physics. 0-Dimensional is a point, 1-dimensional is a line, 2-dimensional is a long and wide (or curved) area, 3-dimensional is 2-dimensional plus the height to form the volume surface. In physics, Time is the fourth
Instance description 1:Slowly changing dimensions. For example, if you register a csdn account with the address, phone number, and other information you fill in, your address will change, but it will change once in a long time. This is a Slow Changing Dimension. See type1, type2, and type3.Type1-full coverage, keep the latest data (keep most recent values in target)Type2-full history (keep a full history of changes in the target)Type3-keep the latest
Gradient Dimension Conversion and Its Implementation
Author: Chen Li
In SQL Server 2005, Bi (Business Intelligence) module functions are greatly enhanced. An important module is called SQL Server Integrated Services (SSIS), which is the SQL Server database integration service, its main function is to extract, convert, and load data from the business database or OLTP database (extract-transform-load, ETL) to the data warehouse ), th
physical model of the Data Warehouse.2. Basic concepts of fact tables and dimension tablesSimply speaking, the dimension table is the angle (dimension) in which you observe the object, and the fact table is what you want to focus on.For example, to analyze the sales of products, you can choose to analyze by product category, or by time, such as the press. The an
In the past, the dimension tables, fact tables, data analysis, BI and other concepts have some ambiguity. These days of study finally let these have some clues:A dimension represents the amount of data you want to analyze , such as when you analyze a product's sales, you can choose to analyze it by category , or by region . Such a press. The analysis forms a dimension
Dimension Modeling Method
Dimension modeling organizes information into structs, which typically correspond to the query methods that analysts want to use for data warehouse data. How much food sales were in the northwest in the third quarter of 1999. Represents the use of three dimensions (product, geography, time) to specify the information to be summarized. Star mode is widely used, in order to do a lot
Overview of SQL Server database dimension tables and fact tables:
Fact table
Each data warehouse contains one or more fact tables. Fact tables may contain business sales data, such as cash register transactions
The resulting data, the fact table usually contains a large number of rows. The main feature of the fact table is that it contains numeric data (facts), and these digital information can be aggregated to provide the relevant units as histori
Introduction fact tables store metric values and Foreign keys of dimension tables. Dimension table angle and category. Time, region, and status. The old method is select * fromorderoinnerjoindistrictdono. discoded. discodein.
Introduction fact tables store metric values and Foreign keys of dimension tables. Dimension t
not be obtained if only these three features are used for classification. Therefore, you can add features such as size and texture. After adding features, the classification results may be improved. But is there more features, the better?
Figure 1 The performance of a classifier does not increase or decrease as the dimension increases
As shown in figure 1, the performance of a classifier increases with the number of features. After a certain value e
Foundataions of machine learning: Rademacher complexity and VC-dimension (2)
(1) growth Function)
Before introducing the growth function, let's introduce an example which will help you understand the growth function.
When the input space is $ \ mathbb {r} $, assume that the space is a threshold function, that is, when the input vertex $ x> V $, The point is marked as positive. For example, Figure 1 shows the six assumptions.
Figure 1 threshold functi
Fact tableEach data warehouse contains one or more fact data tables. Fact data tables may contain business sales data, such as data generated by cash registration firms. Fact data tables usually contain a large number of rows. Fact data tables are mainly characterized by digital data (FACTS) that can be summarized to provide relevant units as historical data, each fact table contains an index composed of multiple parts. This index contains the primary key of the foreign key's correlated latitude
results. Second, the difference between the middle level and the grade of the dimensionWhen defining dimensions in OLAP , layers (Hierarchy) and levels are two confusingconcepts. Simply put, a layer is a classification of dimension members, which is the inclusion relationship between dimension members or dimension member properties. A
0x00 Preface
The following content, is the author in the study and work of some summary, of which the concept of most of the content from the book, the practical content mostly from their own work and personal understanding. Due to the lack of qualifications, there will inevitably be many mistakes, I hope to criticize. Overview
The Data warehouse contains a lot of content, which can include architecture, modeling, and methodologies. For specific work, it can include the following: A data archit
Here's a brief talk of SCD.Put two useful link addresses before you speak. The author's two papers explain what SCD is and how it is appliedHttp://www.cnblogs.com/biwork/p/3363749.htmlHttp://www.cnblogs.com/biwork/p/3371338.htmlSlow changing dimension translation comes down to the slowly changing dimension. It is applied to the loading of dimension table data in
We often encounter this problem in the design of the Data Warehouse: If the dimension has only one attribute in the dimension design, is the choice to create a single dimension for this attribute, or will the attribute of that dimension be placed directly in the fact table as part of the fact table?Suppose there is a
Js one-dimensional array, multi-dimensional array and Object Mixed use method, js dimension
The main purpose of this article is to explain the mixed use of JavaScript arrays and objects. Due to the weak check feature of JS, different types of variables can be stored in the JS array at the same time, for example, you can place numbers, strings, characters, objects, and other content in the same array. Objects can also do the same thing. The difference
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.