Tài liệu Module 6: Working with Cubes and Measures docx

Contents Overview 1 Introduction to Cubes 2 Working with Cubes 5 Introduction to Measures 11 Lab A: Creating Cubes with the Cube Editor 15 Working with Measures 19 Defining Cube Properties 28 Using the Disabled Property 30 Lab B: Using Properties in the Cube Editor 32 Review 35 Module 6: Working with Cubes and Measures BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY Information in this document is subject to change without notice. The names of companies, products, people, characters, and/or data mentioned herein are fictitious and are in no way intended to represent any real individual, company, product, or event, unless otherwise noted. Complying with all applicable copyright laws is the responsibility of the user. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose, without the express written permission of Microsoft Corporation. If, however, your only means of access is electronic, permission to print one copy is hereby granted. Microsoft may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document. Except as expressly provided in any written license agreement from Microsoft, the furnishing of this document does not give you any license to these patents, trademarks, copyrights, or other intellectual property.  2000 Microsoft Corporation. All rights reserved. Microsoft, BackOffice, MS-DOS, Windows, Windows NT, <plus other appropriate product names or titles. Replace this example list with list of trademarks provided by copy editor. Microsoft is listed first, followed by all other Microsoft trademarks in alphabetical order. > are either registered trademarks or trademarks of Microsoft Corporation in the U.S.A. and/or other countries. <This is where mention of specific, contractually obligated to, third party trademarks, which are added by the Copy Editor> The names of companies, products, people, characters, and/or data mentioned herein are fictitious and are in no way intended to represent any real individual, company, product, or event, unless otherwise noted. Other product and company names mentioned herein may be the trademarks of their respective owners. Module 6: Working with Cubes and Measures iii BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY Instructor Notes Other modules in this course review the mechanics for creating different types of dimensions and how to solve common online analytical processing (OLAP) design issues. Though dimensions are fundamental to multidimensional reporting, the database cube combines dimensions with measures to answer complex business questions. In this module, students use the Cube Editor in Microsoft ® SQL Server ™ 2000 Analysis Services to create and manipulate cubes, add measures and dimensions, and assign properties to improve cubes. After completing this module, students will be able to: ! Define the required components of cubes. ! Create cubes by using the Cube Editor. ! Describe the characteristics of measures. ! Assign properties to measures. ! Modify cube properties by using the Cube Editor. ! Disable levels of shared dimensions. Materials and Preparation This section provides the materials and preparation tasks that you need to teach this module. Required Materials To teach this module, you need Microsoft PowerPoint ® file 2074A_06.ppt Preparation Tasks To prepare for this module, you should: ! Read all of the student materials. ! Read the instructor notes and margin notes. ! Practice the lecture presentation and demonstration. ! Complete the lab. ! Review the Trainer Preparation presentation for this module on the Trainer Materials compact disc. ! Review any relevant white papers that are located on the Trainer Materials compact disc. Presentation: 60 Minutes Labs: 30 Minutes iv Module 6: Working with Cubes and Measures BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY Other Activities Difficult Questions Below are difficult questions that students may ask you during the delivery of this module and answers to the questions. These materials delve into subjects that are within the scope of the module but are not specifically addressed in the content of the student notes. 1. Will the Validate Cube Structure tool in the Cube Editor find most problems with a cube? The Validate Cube Structure tool does not find most problems associated with a cube. It notifies you if a cube does not contain at least one measure and at least one dimension. In addition, it notifies you if not all tables in the cube schema are joined to at least one other table. However, most errors in a cube are found in the underlying data in the fact table and dimension tables. Therefore, the only method of ensuring that the cube is complete and error-free is to process the cube, to watch for errors in the Process dialog box, and to verify correct data values within a cube browser. 2. How can you move easily from the Cube Editor to the Dimension Editor to update shared dimensions? There is no way to easily move from the Cube Editor to the Dimension Editor. You must first close the Cube Editor and then open the Dimension Editor for that dimension. In addition, you cannot minimize the Cube Editor or any windows in Analysis Manager. 3. How do you add a measure to a cube when the measure is not in the fact table? All measures must be found in the fact table defined in the cube schema. If your cube requires a measure from another fact table, you can create a view in the relational database management system (RDBMS) and build a cube directly from the view. You can also create another cube with the same dimensions and then create a virtual cube that combines the measures of the two cubes and their shared dimensions. 4. How do you model measures that require a hierarchy, such as a chart of accounts? Because the measures dimension is flat, you cannot create a hierarchy by defining the accounts as measures. However, you can model the accounts as a parent-child dimension. If you are defining typical measures as members in a dimension, you can create a single measure, Amount, because cubes require at least one measure. Then, you use a custom roll-up to assign various aggregations to each of the accounts in the parent-child dimension. Module 6: Working with Cubes and Measures v BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY Module Strategy Use the following strategy to present this module: ! Introduction to Cubes Explain the characteristics of cubes. Discuss the programmatic limitations associated with cubes and measures. ! Working with Cubes Describe the Cube Editor interface and give an informal demonstration of each of the Cube Editor areas. Explain the steps involved in creating a new cube by using the Cube Editor. Describe the differences between defining private and shared dimensions in a cube. ! Introduction to Measures Define the characteristics of measures. Explain the process of adding new members to a cube, deleting measures from a cube, and modifying measures in the Cube Editor. Finish the discussion with lab A, in which students create simple cubes, add dimensions and measures, and view properties in the Cube Editor. ! Working with Measures Describe each of the measure properties found in the Cube Editor. Explain each of the Aggregate Function properties and give examples of when to use Sum, Count, Min, Max, and Distinct Count. Define derived measures and discuss their limitations in creating calculations. ! Defining Cube Properties Explain each of the cube properties available in the Cube Editor. Discuss the real-world application of each property. ! Using the Disabled Property Explain the Disabled property used in the Cube Editor to disable dimension levels. Finish the module with lab B, which highlights several measure, dimension, and cube properties. Module 6: Working with Cubes and Measures 1 BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY Overview ! Introduction to Cubes ! Working with Cubes ! Introduction to Measures ! Working with Measures ! Defining Cube Properties ! Using the Disabled Property It is important to understand the mechanics of creating dimensions, but dimensions are useful only when incorporated into a cube. The database cube combines dimensions with measures to answer complex business questions. In this module, you use the Cube Editor to create and manipulate cubes, add measures and dimensions, and assign properties to improve cubes. After completing this module, you will be able to: ! Define the required components of cubes. ! Create cubes by using the Cube Editor. ! Describe the characteristics of measures. ! Assign properties to measures. ! Modify cube properties by using the Cube Editor. ! Disable levels of shared dimensions. Topic Objective To provide an overview of the module topics and objectives. Lead-in In this module, you will learn about the Cube Editor and how it can be used to create and manipulate cubes, add measures and dimensions, and assign properties to improve cubes. 2 Module 6: Working with Cubes and Measures BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY # ## # Introduction to Cubes ! Characteristics of Cubes ! Analysis Services Limitations An online analytical processing (OLAP) cube uses dimension hierarchies to summarize measures from a fact table. A cube must always have at least one dimension, at least one measure, and one fact table that is the data source of the cube. To efficiently design cubes that meet your business needs, you need to understand the requirements related to cubes and measures and the design limits of Microsoft ® SQL Server ™ 2000 Analysis Services. This section describes the characteristics of cubes and the limitations associated with cubes and measures. Topic Objective To introduce the concept of cubes. Lead-in In this section, you learn the characteristics of cubes and the limitations associated with cubes and measures. Module 6: Working with Cubes and Measures 3 BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY Characteristics of Cubes ! Combine Dimensions and Measures ! Provide the Mechanism for Uniform and Rapid Query Response ! Are Subsets of Data from a Data Warehouse that Are Converted to Multidimensional Structures ! Contain Precalculated Summaries of Data Called Aggregations ! Contain up to 128 Dimensions Users interact with OLAP databases by connecting to and manipulating cubes. The following are important characteristics of cubes: ! Cubes combine dimensions and measures into one logical storage medium. ! Cubes provide the mechanism for rapid and uniform response to complex queries by users. ! Cubes usually contain subsets of data pulled from a data warehouse at the lowest level that are then organized into multidimensional structures and aggregated into more summarized levels. Relational OLAP (ROLAP) cubes store data in a collection of tables found in the source relational database management system (RDBMS). ROLAP cubes store their data in tables, but they have the option to store dimension data in multidimensional structures. ! Cubes contain summaries of data called aggregations, which precalculate according to the aggregation design of the cube. ! Despite their three-dimensional description, cubes typically contain many dimensions, with the programmed limitation of Analysis Services being 128 dimensions. Topic Objective To describe the fundamental characteristics of cubes. Lead-in Now let us discuss the fundamental characteristics of cubes. Delivery Tip Point out that cubes can store data directly in the RDBMS. The slide mentions the most common method of storing cube data in multidimensional structures, but there are other options for storing cube data in Analysis Services. Note 4 Module 6: Working with Cubes and Measures BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY Analysis Services Limits LimitItem 65,535Calculated members per cube 1,024Measures per cube 256Levels per cube 128Dimensions per cube 64 kilobytesRecord size for cube’s source database table When designing cubes and measures, you need to know the programmable limits of Analysis Services. In most cases, the limits far exceed real-world requirements. However, cube and measure requirements sometimes require changes because of the limitations. The following table lists some published limits of Analysis Services. Item Limit Dimensions per cube 128 Levels per cube 256 Measures per cube 1,024 Calculated members per cube 65,535 Record size for cube’s source database table 64 kilobytes Topic Objective To describe the programmed limits associated with cubes and measures in Analysis Services. Lead-in When designing cubes and measures, you need to understand the programmable limits of Analysis Services. Delivery Tips Review each of the limits, using the slide to illustrate the discussion. Ask students whether any limit might be a problem for them when they design cubes for their business needs. [...]... characteristics and mechanics of measures is fundamental to working with cubes ! Defining Measures ! Adding, Deleting, and Modifying Measures Measures are the numeric data of primary interest to the users of a cube Understanding the characteristics and mechanics of measures is fundamental to working with cubes BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY 12 Module 6: Working with Cubes. .. other cubes You can then create virtual cubes that combine multiple source cubes Note For more information about virtual cubes, see module 12, Working with Virtual Cubes, ” in course 2074A, Designing and Implementing OLAP Solutions with Microsoft SQL Server 2000 BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY 26 Module 6: Working with Cubes and Measures Working with Derived Measures. . .Module 6: Working with Cubes and Measures 5 # Working with Cubes Topic Objective To introduce the basics of working with cubes Lead-in In this section, you explore the basic elements of the Cube Editor and learn how to use it to create and edit cubes ! Working with the Cube Editor ! Creating a New Cube ! Setting Dimension Properties The Cube Editor is one of the primary interfaces for refining and. .. cube, and then close the Cube Editor BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY Module 6: Working with Cubes and Measures 19 # Working with Measures Topic Objective To introduce the mechanics of working with measures ! Aggregating Measures ! In this section, you will learn about basic measure properties, the Aggregate Function property, and the use of derived measures in cubes. .. later to refine the cube and measures BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY 6 Module 6: Working with Cubes and Measures Working with the Cube Editor Topic Objective To describe how to work with the Cube Editor ! If you are familiar with the Dimension Editor, the Cube Editor is a very straightforward interface for working with cubes and measures Delivery Tip Open the... by using the Cube Editor ! Add measures and dimensions to a cube Prerequisites Before working on this lab, you must have: ! Experience working with dimensions ! An understanding of dimensions, cubes, and measures Estimated time to complete this lab: 10 minutes BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY 16 Module 6: Working with Cubes and Measures Exercise 1 Creating a... PURPOSES ONLY Module 6: Working with Cubes and Measures 25 include dimensions that use custom rollups or custom member formulas with Distinct Count measures ! Analysis Services cannot fully precalculate cubes containing Distinct Count measures because they are nonadditive measures Therefore, it is recommended that you separate Distinct Count measures into separate cubes so that other measures can take... Dimensions and Cubes, ” in course 2074A, Designing and Implementing OLAP Solutions with Microsoft SQL Server 2000 BETA MATERIALS FOR MICROSOFT CERTIFIED TRAINER PREPARATION PURPOSES ONLY Module 6: Working with Cubes and Measures 11 # Introduction to Measures Topic Objective To introduce the concept of measures Lead-in Measures are the numeric data of primary interest to the users of a cube Understanding... PURPOSES ONLY Module 6: Working with Cubes and Measures 13 The Measures Dimension The following items are characteristics of the measures dimension: ! The measures dimension is flat—there are no levels in the dimension ! The measures dimension is limited to 1,024 members, each of which maps directly to one or more columns in the source fact table ! You do not share measures across multiple cubes The measures. .. CERTIFIED TRAINER PREPARATION PURPOSES ONLY 14 Module 6: Working with Cubes and Measures Adding, Deleting, and Modifying Measures Topic Objective To describe how to add, delete, and modify measures by using the Cube Editor ! ! After a cube is defined, the only way to add, delete, or modify a measure is by using the Cube Editor Key Point Adding, deleting, or modifying measures in a production cube is a major . learn the characteristics of cubes and the limitations associated with cubes and measures. Module 6: Working with Cubes and Measures 3 BETA MATERIALS. and manipulate cubes, add measures and dimensions, and assign properties to improve cubes. 2 Module 6: Working with Cubes and Measures BETA MATERIALS