VI Datagen Input Object

The Visual Integrator (VI) Datagen input object provides data generation capability within VI scripts.

VI Datagen Icon

A Datagen object creates a specified number of rows containing integer sequences or other types of randomized data.

The Datagen input object has Closedthree panes where you set attributes.

VI Datagen All Panes

You set attributes for the Datagen object in the Closedobject attributes pane.

VI Datagen Attributes

Attribute Description

Count

(required)

 Defines the number of rows to generate. Count is set to generate 100 rows by default. The maximum number of rows allowed is 2,147,483,647.
Seed Defines the seed to use to initialize the pseudo-random number generator. Using a seed allows you to regenerate the same set of values. Otherwise, each time the script runs, it generates a new data set. Set a non-zero integer, and the generated random data is based on this seed. If set to zero or not set, the seed is the time that the script runs.

Each object has an area where you can enter comments.

It is a DI best practice to enter a note for every object in a VI script. You can set a VI preference to give a warning for each object without a note. For more information, see Visual Integrator Preferences.

ClosedDatagen object with comments.

VI Object Coments and Notes

The ClosedDatagen column grid is where you provide details about the columns to be created in the generated Closedoutput table.

VI Datagen Sample Grid

VI Datagen Output Table

Attribute Description
name Specifies a name for the generated column.
type

Specifies the generating type for the column, which controls the contents and the randomness of data. The type attribute can have the following values:

  • city—A random American city or town.
  • date—A random date in standard DI date format: YYYY/MM/DD, chosen from the start date through the end date.
  • decimal—A random two-decimal place number, chosen from within the min and max attributes inclusively.
  • firstname—A random first name, based on the 1000 most popular American first names.
  • integer—A random integer, chosen from within the min and max attributes inclusively.
  • lastname—A random last name, based on the 1000 most popular American last names.
  • month—A month string. For example: January, February, or December.
  • name—A concatenation of a random first name and a random last name. For example, John Smith.
  • sequence—An integer sequence, starting from the start attribute to the end attribute. If more rows are required after the sequence reaches the end number, the sequence starts again with the start value.
  • state—A two-character US state code.
  • strings—A string, chosen from the strings listed in the strings array attribute.
  • word—A random pronounceable word of a specified length or range of lengths. This value might not be an actual word.
  • zip—A random number between 01000 and 99999, in five-digit zip-code format. It does not necessarily correlate with generated city or state columns.
distribution

Specifies the distribution of random values. Distribution is valid for all generating types except sequence. Values include:

  • linear (default)—Specifies an even linear distribution. Each possible value appears with the same frequency.
  • standard—Specifies a bell curve distribution, centered at the midpoint of possible values, with a standard deviation of a quarter of the range. For example, a standard distribution of random integers with min=0 and max=100 is a distribution centered at 50, with a standard deviation of 25. Over half the values are between 25 and 75.
  • By fixing the standard deviation to be one quarter of the range, standard distribution values outside two standard deviations will not fit inside the range and will not be in the output. This will result in higher tails than normal.
  • 80-20—Specifies a random distribution that corresponds to an 80-20 Pareto rule found in many data sets where a small number of discrete values (10%-20%) contain 80%-90% of the total data. This distribution, valid for non-decimal data, sorts all possible values using a random permutation and chooses the sorted values using an exponential distribution. This results in an 80-20 distribution and requires memory corresponding to eight bytes per possible output value. It is not recommended for selections of more than 50,000 possible values.
start

Specifies a starting point.

  • date type—Specify the beginning of the date range. Use standard DI date format: YYYY/MM/DD.
  • sequence type—Specify the beginning of the sequence. The default value is 1.

Applies to sequence or date types only.
end

Specifies an ending point.

  • date type—Specify the end of the date range. Use standard DI date format: YYYY/MM/DD.
  • sequence type—Specify the end of the sequence. The default value is the value of the count attribute.

Applies to sequence or date types only.
min

Specifies the lowest possible integer or decimal value to generate.

Applies to integer and decimal types only.
max

Specifies the highest possible integer or decimal value to generate.

Applies to integer and decimal types only.
length

Specifies the maximum length of a word. The default value is 8.

Applies to word type only.
min_length

Specifies the minimum length of a word. The default value is the value of the length attribute.

Applies to word type only.
capitalize

Specifies capitalization for the string in the generated output data flow.

Applies to word type only.
strings

Specifies an array of string values that the strings generating type uses. See type attribute.

  1. Click the strings button for a table row using the strings type.

    The ClosedEdit 'strings'-value for <'row_name'> dialog box appears; for example, Edit 'strings'-values for 'GenStrings.

    VI Datagen Edit Strings

  2. Enter a string, and press Enter.

  3. Repeat step 2 until the list of strings is complete.

  4. Click OK.

    The array of strings is now available for this row.

    NOTE: If you add an array of strings to a row that is not a strings type, the type is automatically changed to strings.

Applies to the strings type only.