Описание тега cognos-tm1
Cognos TM1 is an in-memory, multi-dimensional, read/write online analytical processing (OLAP) tool which can be used for data warehousing, budgeting and planning, reporting or analysis of data.
It typically works on a client / server model in which the server side of the application resides on either a Windows Server or a Unix computer on the network. This part of the application, also called the TM1 server, stores the data and regulates access to it. All of the data is stored in the server's memory and is only read from disk (in most cases) when the server starts, contributing to the server application's speed but demanding a high memory capacity server. Initial calculations which are derived from input data are done on demand, but will be cached until the underlying data changes. The server has a calculation language called Rules which allows calculations similar to Excel to be done, but on larger data sets and with all of the calculations centralised on the server. The server is optimised for sparse storage, meaning that it handles the situation where large blocks of a cube (defined below) are empty.
A version of TM1 named Perspectives also allows users to run a TM1 server on their own desktop for analysis purposes. This is referred to as a Local Server. In most ways it functions similarly to a standard networked TM1 server but only the user who is running it can connect to it.
Various client software can access the data that exists on a server. Historically the most common client was an add-in for Microsoft Excel (and, previously, Lotus 123) which allows the user two way interaction with the data on the server via special worksheet formulas called =DBRW()s, amongst others. A web server is also available to allow users to interact with the data via a browser interface. For most of its life TM1 was distributed by a company called Applix but was acquired by Cognos in 2007. (Which was in turn acquired by IBM later that year.) Cognos has been increasingly integrating TM1 into its Enterprise Resource and Planning (ERP) products as the back-end calculation engine to Cognos front-ends. The TM1 software also offers several separate APIs (one for C++/VB6/VBA, one for VB.Net and C#, one for Java) of varying levels of functionality, which makes it possible, if not always easy or practical, for users to write their own applications which connect to the server engine.
TM1 is multidimensional in that its data is held in "cubes". Each cube is made up of dimensions, each of which represents a characteristic of the value stored. (Eg the company, the profit centre, the account, the version, etcetera.) Each element within the dimension represents a specific characteristic, such as the name of the profit centre, the name of the account, and so on. Some elements represent consolidations (aggregations) of other elements; for example the consolidated element "Total Revenue" may be made up of all of the revenue elements in the Account dimension. To locate specific values within a cube, the user specifies one or more elements from each of the dimensions. In this way they can create a grid of values.
The fact that TM1 is read/write allows it to be used for collaborative budgeting and forecasting, where users from multiple sites can be inputting budget numbers at the same time, with someone in head office reviewing them in real time.
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