Sampling page

Data stores sampled or not sampled. The Data Sampling function can be used to display the content of the data elements or a sample of the values contained in the data elements with the number of occurrences for each of them. The Data Sampling phase provides the following information:

  • Up to 1000 different values for each data element, with their frequency and the frequency of the 999 ranges defined by the 1000 values (standard sampling).
  • Fingerprints (compressed sampling). This is a visual representation of the statistical distribution, in a compressed format, of the data element content.
  • The concise representation of the content of a data element depends on the nature of the data element:
    • The values of numeric data elements are divided into homogeneous groups differentiated by the value of their first digit and the number of digits they include. This description preserves the general representation of the values distributed in the data element.
    • The values of alphanumeric data elements are organized according to several criteria, including: First character, value length, presence of numeric characters only, presence of alphabetic characters only.

The number of values belonging to each class is stored for each of these criteria, which allows the data element content properties to be preserved. If you want to process the compressed sampling, the minimum and maximum values of each sampled data element can also be calculated.

To access the data sampling function, click the tab or click (View Data Stores by Sampling) on the toolbar.

Icon Description
Activated Data stores with data elements that have been sampled.
Deactivated Data stores that contain no data elements with sampling activated.
Sampled Data stores that contain sampled data elements.
Not Sampled Data stores that contain no sampled data elements.

The first two icons can be combined with the second two to give four different combinations.

The following options are accessed by right-clicking a selected data store in the Work with Data Stores area on the Sampling page:

Option Description
Open Selected Data Store Displays a window, which shows all the objects associated with the data store (Work with Data Stores area).
Data Store Properties Displays a window with all the information about the data store.
Delete Selected Data Store Starts a job and deletes highlighted data stores from the Knowledge Base.
Work with Data Elements of the Selected Data Elements Displays the data element details window, filtered for the currently selected data store.
Show Synthetic Data Element Contents Shows the statistical distribution of values in graphical form about the sampling of data elements within the selected data store.
Schedule Jobs Shows a submenu used to schedule jobs for the selected data store. (Data Express for z/OS only).
Enable/Disable Sampling Enables and disables the sampling function.
Export to File Exports the list of displayed data to a file of the chosen type.
Filter Active Independently of the data store selected, applies selections to the list of data stores.