tailieunhanh - Hướng dẫn học Microsoft SQL Server 2008 part 152

Dữ liệu cũng có thể được còn lại trong cơ sở dữ liệu quan hệ, hoặc ROLAP lưu trữ, mà thường kết quả trong thời gian chế biến nhanh nhất tại các chi phí của lần truy vấn. Nếu không có aggregations, truy vấn đối với một cửa hàng ROLAP gây ra tương đương với SQL được thực thi khi cần thiết. Aggregations có thể được tính trước để ROLAP, nhưng làm như vậy đòi hỏi phải xử lý tất cả các dữ liệu chi tiết, vì vậy MOLAP là lựa chọn ưa thích. . | PartX Business Intelligence Data can also be left in the relational database or ROLAP store which generally results in the fastest processing times at the expense of query times. Without aggregations queries against a ROLAP store cause the equivalent SQL to be executed as needed. Aggregations can be pre-calculated for ROLAP but doing so requires processing all the detailed data so MOLAP is the preferred option. A relational database in this context is not limited to SQL Server but may be any data source for which an OLE DB provider exists. A compromise between the speed of MOLAP storage and the need for preprocessing called proactive caching serves queries out of MOLAP storage when possible but queries the relational database to retrieve the latest data not yet processed into the MOLAP store. Finally the Analysis Services server uses XML for Analysis XMLA as its sole protocol which is why you see XMLA inside the arrow in Figure 71-1. Client Clients communicate with Analysis Services like any other Web Service via the Simple Object Access Protocol SOAP . Client applications can hide XMLA and SOAP details by using the provided data access interfaces to access Analysis Services All .NET languages can use . Win32 applications such as C can use the OLE DB for OLAP driver. Other COM-based applications such as VB6 VBA scripting can use ADOMD. While the server will only speak XMLA via TCP IP clients have the option of using the HTTP protocol for their communications if an appropriately configured IIS server is available to translate. In addition to custom applications Analysis Services can be accessed by several provided tools including the following Business Intelligence Development Studio for defining database structure SQL Server Management Studio for managing and querying the server Reporting Services which can base report definitions on Analysis Services data Excel features and add-ins for querying and analyzing data A wide variety of third-party tools are .