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Summary > Self-test

Self-test

Self-test Question: For the most part, what will be the information in TM1? Response: The information in TM1 will be trended over time, compared between different time periods, and forecasted for future time periods. Question: To support these requirements, how will most TM1 cubes have time added? Response: The TM1 cubes will have time added as one (or more) dimension. Question: Of all the considerations for deciding what dimensions should make up a TM1 cube, what may be the most important? Response: Time is one of the (if not the most) important considerations. Question: What is the role of the time dimension? Response: The role of the time dimension is to allow the analysis of past, present, and future information as well as to support the ability to predict the future (also known as forecasting). Question: When considering the concept of time in a TM1 cube, what do you need to determine? Response: You need to determine the lowest level of time detail required, if the data in your cube requires regular and consistent time cycles, if the data in your cube requires any unusual, overlapping, or inconsistent time cycles, and if your cube will require any rolling time periods. Question: What are the four basic types of cubes in Cognos TM1? Response: Standard cubes, control cubes, virtual cubes, and lookup cubes. Question: Name three important considerations when adding TIME to your cube design. Response: The considerations are as follows: Will your cube be sharing data with other cubes already in your system?What will be the level of effort that may be required for the end user when accessing data?What will be the level of effort required to load data from external systems? Question: In respect to maintaining TIME in your model, what must be considered? Response: You must consider flexibility when comparing data across multiple time periods, flexibility when creating new consolidated time periods in the future, the maintenance effort required to update time dimension(s) as new cycles are added, and your rules—since the left hand side of a rule must be a fixed reference, you really don't want to have to maintain them every year because of your time dimension design. Question: What is granularity? Response: Granularity is the lowest level of time detail required. Question: What are the most common granularities for a time dimension? Response: Month, Week, and Day. Question: Cognos TM1 cubes that store data at the monthly level of detail may have one or two time dimensions. If you have two, what would this mean? Response: It would mean that you have one dimension for the year and one dimension for the month. Question: Why would you have both a year and a month dimension, in the same cube? Response: It is easier for year on year comparisons, it will require less maintenance for the system administrator, requiring that only a single element needs to be added to the year dimension once a year, and it is easier to take advantage of TM1's relative data spreading. Question: Describe a rule of thumb when using a two dimensional time model. Response: A rule might be that the year and month dimensions should conform to the financial year of the business. Question: What may the consolidated elements of the month dimension also include? Response: Year totals, Quarter totals, Half-year totals, and optionally Quarter to Date totals and Year to Date totals. Question: For non-financial cubes, what should the year and month dimensions use to make the structure more appropriate? Response: A calendar year (with a set of months running from January to December). Question: When can using a single time dimension be more useful? Response: If the application requires rolling totals for example, it is easier to model these using consolidations in a single time dimension rather than using rule calculations in a cube that has separate year and month dimensions. Question: What may be an advantage of using a single time dimension? Response: Single time dimensions may also make the development of some rule calculations more straightforward. Question: In the case where there is a requirement for rolling totals, how is time usually modeled? Response: Time is usually modeled using consolidations in a single time dimension rather than using other options such as rule calculations or having separate year and month dimensions. Question: Name some characteristics of a single time dimension. Response: Support requirements such as rolling forecasts make rule writing somewhat easier, and may be easier to maintain by a system administrator. Question: For cubes that must store weekly information the best approach may be to have two time dimensions. Which would be these dimensions? Response: One dimension for year and one dimension for week. Question: What challenges does the use of a week dimension create? Response: A 365 or 366 day year does not contain an exact number of weeks and a 29, 30, or 31 days month does not contain an exact number of weeks. Question: What will using a 52 week system result in? Response: The days that are assigned to each year becoming more and more out of synchronization with the calendar year as years pass. Question: How should week dimensions be set up? Response: With 53 weeks, not 52. Question: If for any reason the time pattern needs to change from year to year, what should be considered? Response: Then a single time dimension will be more appropriate. Question: How are single week-based time dimensions usually built? Response: The single week-based dimensions are based upon a business calendar with the appropriate number of weeks rolling up to each month. Question: What does using a single time dimension allow? Response: It allows the creation of any possible grouping of individual dates. However, it requires the most amount of maintenance and affords the least amount of flexibility when performing period on period comparisons. Question: If data needs to be stored at a lower level of detail than day, what is normally required? Response: Then an additional dimension should be added for the day part. Question: What is one of the most commonly requested requirements for Cognos TM1 dates? Response: The ability to select and display the date in a variety of formats. Question: Although there are a number of supported TM1 functions that you should be comfortable with, what are some alternative methods for formatting TM1 dates? Response: Most date format reporting requirements can be met using MS Excel formulas. Question: In addition to defining an element's type, what can elements have defined for them? Response: Elements can have attributes defined for them. If elements identify data in a cube, then think of the element attributes as describing the elements themselves. Question: What is the method for formatting dates in TM1? Response: Attributes with alternative date formats can help in doing data analysis by making it easier to search for and locate a particular date. Question: What could be the advantage of using element attributes? Response: You can select elements by attribute value in the Subset Editor. You can also display element names in TM1 windows using their aliases. Question: What are some (but not all) of the common time dimension consolidations used for aggregation to be aware of? Response: Week, Month, Quarter, Year, Fiscal Year, QTD, and QTG. Question: In most cases, the initialization of the model will include multiple forward years so that the time dimension maintenance will almost be non-existent for the foreseeable future. What does this mean? Response: This means that the time dimension will include multiple dates past the current and next calendar and/or fiscal years. This is referred to as future proofing the time dimension. Question: In some cases, it may be important to only include currently used or active dates in the time dimension. Why? Response: Dates can simplify the use of the model enhance readability or discourage possible errors in reporting. In these cases, a method needs to be defined to allow the addition (or removal) of dates which is currently needed (or no longer needed) within the model. Question: When may it be completely acceptable for a TM1 Administrator to manually modify a time dimension using the TM1 Dimension Editor? Response: Depending upon the size of the application and/or number of users (and other factors). Question: What is another method for maintaining a TM1 time dimension? Response: In some situations a TI process may be useful to accept appropriate parameters and then update the time dimension. Question: Name some Cognos TM1 functions that deal with dates and times. Response: DATE, DATES, DAY, DAYNO, MONTH, NOW, TIME, TIMST, TMIVL, TODAY, and YEAR.

  

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