Developing ssas cube

Editor's Notes

• #9: SQL Server Management StudioWhen you start SQL Server Management Studio, it connects directly to the Analysis Services server and immediately performs the requested operation.For example, if you process a cube or a dimension, internally the system uses the new managed API called Analysis Management Objects (AMO) to look up information and request management functions, such as object processing. Some operations are done via AMO and some use XMLA scripting. In either case, the operations are performed immediately against the live Analysis Services server. Since Analysis Services supports concurrent access, the system maintains locking structures that block multiple operators from performing conflicting operations. For example, these structures prevent an operation from deleting a dimension at the same time that another operation is processing the dimension.SQL Server Management Studio is designed as a management utility. It is not a development environment. It allows you to browse the Analysis Services server and perform various operations-related activities, such as performing backups and restores, synchronizing servers, and configuring servers. While SQL Server Management Studio can perform basic object manipulation, such as changing minor properties or deleting objects, it relies on other programs to design and deploy Analysis Services objects.BI Development Studio in project mode (default)A developer or database administrator (DBA) who wants to design and implement an Analysis Services database uses BI Development Studio to interact with Analysis Services. BI Development Studio is built using the Microsoft Visual Studio® shell. Performing operations in BI Development Studio is similar to performing operations with other SQL Server tools (such as creating an Integration Services package or a Reporting Services report) and with other programming tools (such as writing a Visual Basic®. NET or Visual C#® program). One of the tenets of the Visual Studio shell is that development is an iterative edit, build, and deploy cycle.For Analysis Services, this means that once you start working with an Analysis Services project, you are disconnected from the Analysis Services server. You initially build the project by either: 1) creating dimensions, cubes, and other objects from relational sources and then deploying the project to the Analysis Services server; or 2) taking an existing Analysis Services database from a server and creating a project from it. Once the project is created, it exists disconnected from the Analysis Services server (and the database that it represents). You can take the project offline with you on an airplane, home with you on your laptop, or how ever you wish. Only when you deploy the project does it reconnect to the Analysis Services server. When you deploy the project, BI Development Studio detects the differences between the objects in the project and what exists on the Analysis Services server. These differences are then applied to the Analysis Services server so that it is synchronized with the project. This might mean creating new objects that you created while offline or editing properties that you changed while offline or even deleting objects if they exist on the Analysis Services server but not in the project.This is very powerful paradigm. Developers develop an application and then compile and deploy it. From then on, the project exists offline on the developer’s workstation, where it can be edited and developed, then recompiled and deployed again. This is the same paradigm that is used for Analysis Services projects.How do developers ensure that no two developers make a conflicting edit to the same piece of application code? They use a source control system. When everyone is working through the same source control system, no two developers can make conflicting changes. The same thing happens with BI Development Studio project files. This also applies to project subfiles, such as the dimension and cube files which make up the project, not unlike the C# program source files that make up an application.BI Development Studio in directly connected modeYou might be thinking that all is right in the world as we’ve outlined two tools: SQL Server Management Studio for operators and BI Development Studio for developers. However, there are circumstances where DBAs and operators need the functionality of BI Development Studio to perform their work. This would be the case, for example, when they need to find out what measures come from which cubes or what the overall schema looks like. To facilitate this, BI Development Studio has a direct connect mode. To access this mode, after starting BI Development Studio, select Open from the File menu and then select Analysis Services database.In this mode, you are not using an offline project file. Instead, you are directly connected to the Analysis Services server. If you create a partition, a cube, or a dimension, you immediately create, update, or delete the object. You are working against the live database. There is no offline editing and thus no deployment or check-in of the underlying files.
• #18: Dimensions are a structural attribute of cubes. They are organized hierarchies of categories and (levels) that describe data in the fact table. These categories and levels describe similar sets of members upon which the user wants to base an analysis.Dimensions can also be based on OLAP data mining models. They can be used to store the results of a mining model analysis and can be browsed within the context of a virtual cube.
• #21: Cube ProcessingAfter making structural changes to a cube, you must process the cube before attempting to browse its data. Process your cube after completing any of the following: Building the cube and designing its storage options and aggregationsChanging the cube's structure (measures, dimensions, and so on) and saving the changes to the cubeChanging the structure of a shared dimension used in the cubeAlso, if data in the cube's data warehouse has been added or changed, processing is recommended in order to ensure accurate results when browsing the cube.When you process a cube, the aggregations designed for the cube are calculated and the cube is loaded with the calculated aggregations and data. Processing a cube involves reading the dimension tables to populate the levels with members from the actual data, reading the fact table, calculating specified aggregations, and storing the results in the cube. After a cube is processed, users can query it.There are three ways to process a cube. If you are modifying the structure of the cube, you may be required to process the cube with the Full Process option. If you are adding new data to the cube, you can process the cube with the Incremental update option. To clear out and replace a cube's source data, you can use the Refresh data processing option.In addition to these three mutually exclusive options, a fourth option can be selected in conjunction with any of these options. This option allows you to incrementally update the cube's dimensions as part of the cube processing. This option is called incrementally update the dimensions of this cube.These options are available in the Process a Cube dialog box, which is displayed when you right-click a cube in the Analysis Manager tree pane and then click Process.Real-Time OLAPProcessing a cube can take a great deal of time, especially for complex cubes with dimensions containing millions of members. Frequently processing cubes based on rapidly changing data, such as data found in online transaction processing (OLTP) databases, can be a difficult task. Very often such cubes contain stale data, with aggregations based on a view of the data that is no longer valid.Real-time OLAP provides a way to automatically process the relational OLAP (ROLAP) dimensions and/or partitions based on Microsoft® SQL Server™ 2000 relational tables when changes to the underlying dimension or fact tables occur. This allows real-time cubes based on rapidly changing data to be automatically updated and always available to end users. For more information about real-time cubes,