An Insertion or Substitution rule will use information from a specified Data Set to modify the contents of the specified table and column.

If there is a requirement for a specific set of substitution data that is unavailable in the standard Data Sets it is quite possible to construct your own Data Set. Building your own Data Set is quite simple - here is how it is done:

Create the data as a standard text file with one item per line.

Give the text file any name you wish (see note 3 and 4 below) but use the extension .udef

Place the file in the Data Masker Data Sets directory along with the standard data sets.

Restart the Data Masker Software. The new data set should now be visible and usable in Insertion and Substitution rules.

Some Notes on User Defined Data Sets

1. Be careful not to allow any blank lines (particularly at the very end of the file) in the text file. The Data Masker will happily accept an empty line as a valid Data Set value and will insert or substitute it as with any other data.

2. Be careful to trim off any leading and trailing space characters from each line. The Data Masker will insert or substitute the data "as-is".

3. The text file containing the data must have an extension of .udef

4. Any underscore "_" characters in the file name will be replaced by spaces when the name appears in the Data Set list inside the Data Masker software. Thus a filename of Endangered_Mammals.udef will appear on the display as Endangered Mammals.

5. As with all Data Sets you do not need to worry about field length considerations. For example, a rule applied to a varchar2(20) field will not receive Oracle errors if there are some lines in the User Defined Data Set that are longer than 20 characters. The Data Masker will ignore the lines in the User Defined Data Set which are too long for the field into which they are being written.

6. It is possible to use all of the sampling and WHERE Clause options with User Defined Data Sets - just as with the supplied Data Sets.

7. It is possible to feed the Data Set into a User Defined procedure - just as with the supplied Data Sets.

8. It is possible to enable "Randomize" and "Unique Values Only" options on User Defined Data Sets.

9. The DataMasker Sample Sets directory contains a sample text file named Endangered_Mammals.udef file which can be copied into the DataMasker DataSets directory to practice using User Defined Data Sets.