Generator

If the column is being used in a Row Generator or Column Generator stage, this allows you to specify extra details about the mock data being generated. The exact fields that appear depend on the data type of the column being generated. They allow you to specify features of the data being generated.

For example, integers allow you to specify if values are random or whether they cycle. If they cycle, you can specify an initial value, an increment, and a limit. If they are random, you can specify a seed value for the random number generator, whether to include negative numbers and a limit.

The following diagram shows the generate options available for the different data types.

All data types

All data types other than string have two types of operation, cycle and random:

• Cycle. The cycle option generates a repeating pattern of values for a column. It has the following optional dependent properties:
  • Increment. The increment value added to produce the field value in the next output record. The default value is 1 (integer) or 1.0 (float).
  • Initial value. is the initial field value (value of the first output record). The default value is 0.
  • Limit. The maximum field value. When the generated field value is greater than Limit, it wraps back to Initial value. The default value of Limit is the maximum allowable value for the field's data type.

    You can set these to `part' to use the partition number (for example, 0, 1, 2, 3 on a four node system), or `partcount' to use the total number of executing partitions (for example, 4 on a four node system).

• Random. The random option generates random values for a field. It has the following optional dependent properties:
  • Limit. Maximum generated field value. The default value of limit is the maximum allowable value for the field's data type.
  • Seed. The seed value for the random number generator used by the stage for the field. You do not have to specify seed. By default, the stage uses the same seed value for all fields containing the random option.
  • Signed. Specifies that signed values are generated for the field (values between -limit and +limit). Otherwise, the operator creates values between 0 and +limit.

    You can limit and seed to `part' to use the partition number (e.g., 0, 1, 2, 3 on a four node system), or `partcount' to use the total number of executing partitions (for example, 4 on a four node system).

Strings

By default the generator stages initialize all bytes of a string field to the same alphanumeric character. The stages use the following characters, in the following order:

abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ

For example, the following string with a length of 5 would produce successive string fields with the values:

aaaaa
bbbbb
ccccc
ddddd
...

After the last character, capital Z, values wrap back to lowercase a and the cycle repeats.

You can also use the algorithm property to determine how string values are generated, this has two possible values: cycle and alphabet.

• Cycle. Values are assigned to a generated string field as a set of discrete string values to cycle through. This has the following dependent property.

  Values. Repeat this property to specify the string values that the generated data cycles through.

• Alphabet. Values are assigned to a generated string field as a character string each of whose characters is taken in turn. This is like the default mode of operation except that you can specify the string cycled through using the dependent property String.

Decimal

As well as the Type property, decimal columns have the following properties:

• Percent invalid. The percentage of generated columns that contain a invalid values. Set to 10% by default.
• Percent zero. The percentage of generated decimal columns where all bytes of the decimal are set to binary zero (0x00). Set to 10% by default.

Date

As well as the Type property, date columns have the following properties:

• Epoch. Use this to specify the earliest generated date value, in the format yyyy-mm-dd (leading zeros must be supplied for all parts). The default is 1960-01-01.
• Percent invalid. The percentage of generated columns that will contain invalid values. Set to 10% by default.
• Use current date. Set this to generate today's date in this column for every row generated. If you set this all other properties are ignored.

Time

As well as the Type property, time columns have the following properties:

• Percent invalid. The percentage of generated columns that will contain invalid values. Set to 10% by default.
• Scale factor. Specifies a multiplier to the increment value for time. For example, a scale factor of 60 and an increment of 1 means the field increments by 60 seconds.

Timestamp

As well as the Type property, time columns have the following properties:

• Epoch. Use this to specify the earliest generated date value, in the format yyyy-mm-dd (leading zeros must be supplied for all parts). The default is 1960-01-01.
• Use current date. Set this to generate today's date in this column for every row generated. If you set this all other properties are ignored.
• Percent invalid. The percentage of generated columns that will contain invalid values. Set to 10% by default.
• Scale factor. Specifies a multiplier to the increment value for time. For example, a scale factor of 60 and an increment of 1 means the field increments by 60 seconds.