In this section:
A datapoint is similar to a field in a table, but with built-in dimensional linkages. It also has linkages back to sources and forward to measures, which provide a clear lineage from harvest point to presentation.
There are four different types of datapoints in PMF:
Note: Most of the information for Loadable, Generated, or User-Entered datapoints are read-only. The only thing you can change about them is their name or description.
The Edit Datapoint panel opens.
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Derived datapoints let you create calculations that include dimensional metadata. For example, you can create a series of derived datapoints that perform a series of calculations on Sales performance for your manufacturing company:
These datapoints can now be added up to become Total Cost (by Product, Location and Time).
You can then set Total Cost against your Sales (by Product, Location and Time) to calculate Profit.
You can also load precalculated Total Costs and Profit datapoints from an external Source, but there is no guarantee the data will be calculated in the proper order. If you use derived datapoints to calculate the values:
Lineage Chains are currently available in the Lineage tabs on dimensions, sources, datapoints, and measures panels.
To create a derived datapoint:
The New Datapoint panel opens.
Calculations can also include constants. To add a constant, drag the Constant object into position on the canvas, and type in the constant value inside the Constant object.
Separate datapoints for WebFOCUS functions are typically created during the source load, since capturing these calculations is done best in the first-generation in the lineage, during harvesting.
For example, if you want to capture counts of a particular condition, rather than trying to save all those attributes somewhere so you can perform the filtering later, you can determine When, that is what filters should be true, for the count. You can then pull that count into a loadable datapoint. Approaching data this way allows you to make calculations in the lineage after this harvesting phase simpler for you to manage.
To change a derived datapoint:
You can make an exact copy of any existing derived datapoint. After making the copy, you can immediately alter it as needed. To copy a datapoint:
All loaded data from a derived datapoint can be wiped out or deleted in a single operation, because they are not attached to a source.
Note: Wiping data affects downstream datapoints for the datapoint you wipe. Every datapoint downstream is marked as having incomplete components. Incomplete components do not participate in recalculation.
Note: It may take PMF a moment to purge all of the data.
PMF allows you to create an unlimited number of calculations for your measures using special datapoints that store and process calculations, known as derived datapoints. These calculations can be based on one or more existing datapoints, of any kind, including loadable, user-entered, generated, and other derived datapoints. Note the following:
Recalculating a complex lineage chain through possibly hundreds of thousands or millions of row values can be an expensive operation, so you have full control over how much of this calculation is performed during normal processing hours.
Note: During scheduled load cycles, since PMF is less used during scheduled load times (usually overnight), recalculation can always go through the entire lineage.
You can preview the data that PMF will generate by clicking the Preview tab, as shown in the following image.
The Preview tab generally shows rows that are new, or will be updated or deleted.
Derived datapoints can have a complex, multi-part lineage, depending on their relationship to other derived datapoints.
You can view lineage for all datapoints for any derived datapoint. Lineage shows the progress of data through PMF, from the external data harvested into datapoints, through any derived datapoints, and finally all terminal points in Measures. The Lineage tab displays the components in the generated source by default, as shown in the following image.
The lineage tab automatically displays the entire lineage. You can click the Collapse All button to hide the entire lineage.
PMF keeps track of each load that is executed for each derived datapoint in the system, regardless of whether you loaded it manually or the load was called by the scheduler. This data is stored in a special logging section of the PMF data mart.
The History tab on each derived datapoint displays the history of all loads that have been logged.
The history of the derived datapoint shows:
Loadable Sources manage Loadable datapoints. You can drill into any datapoint on a Loadable Source to view the specifics about the datapoint, or you can access Loadable datapoints from the separate panel button for them.
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Generated Sources manage Generated datapoints. You can drill into any datapoint on a Loadable Source to view the specifics about the datapoint, or you can access Loadable datapoints from the separate panel button for them.
Generated datapoints are designed for the following situations:
Generated Datapoints are primary sources for data in PMF. They are treated as first generation in any lineage, along with loadable datapoints and user-entered datapoints.
Generated datapoints are used when you lack real data to prove that your model works, or they are needed for a demonstration. Once you are ready to use a working model with real data, generated datapoints are no longer necessary to feed your metrics.
To promote the generated datapoint:
User Entered Sources manage User Entered datapoints. You can drill into any datapoint on a Loadable Source to view the specifics about the datapoint, or you can access Loadable datapoints from the separate panel button for them.