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Oddball Feature Request: Generation of Temporary Column, etc

DAndres109@aol.comDAndres109@aol.com Posts: 22 Bronze 2

Consider the following schema:

Table A:
Col1: int
Col2: int
Col3: int
Col4: int
Total: int

I need to be able to ensure the following invariant is true for a each generated row:

Total = random(min, max)
Random % of Total = (Col1 - Col2) + (Col3 - Col4)

A couple of really great features would be nice here:

1. The Total column can be configurable as a random quantity (already supported, but would need to be extended to support the items below)

2. The Random % of Total is a temporary, configurable value that is used solely for deriving an end result to formulae involving other columns. In this case, it is a percentage of the value picked by #1.

3. Col1 through Col4 will be randomly generated (configurable, possibly by min/max percentage of some column value, would be awesome) and will add up, per a given formula, to the value picked by #2.

I guess what I'm asking for is to be able to generate data on a row-basis as well as the current method, which is by column. To be able to interrelate columns in the same row would be very helpful.


David Andres


  • Options
    Hi David,

    Thanks for the post. It is not such a odd feature request.

    If I understand correctly, to solve your requirement you want to be able to:

    1) Define an expression to generate the data based on other columns in the row. Similar to how you define a computed column in SQL Server?

    2) Have a set of rules governing how the data is created for each column on a row by row basis?

    I have added your post into our system, and we will review it for our next release. If you could confirm my two points above that would really help us for planning the feature.


  • Options

    That's a fair summary of my needs at this point.

    Essentially, each row could have a set of variables (randomly valued) that can be referred to by expressions for selected columns, and each column can refer to other columns within the same row (to ensure that the figures match up).

    I recently completed a project where I needed to ensure the following:

    1. Given a randomly generated total Total T, calculate Quantity X as a percentage (between 0 and 20) of that total.
    2. Quantity X is really the end result of a formula involving four table columns (referred to as A, B, C, and D), so I wanted to be able to distribute randomly across these four columns while still maintaining the rule that they must add up to Quantity X.

    In this scenario, I first calculated the percentage I needed to obtain Quantity X, and calculated the other values based on random portions of this percent. For example, given:

    X %: 15
    A %: Random(0, X%)
    B %: Random(0, X% - A%)
    C %: Random(0, X% - A% - B%)
    D %: X% - A% - B% - C%

    All of which are then multiplied by Total T to get the values I need.

    Hopefully, this can be more generalized then what is described here. I think it is complicated, but seems useful to be able to do for particularly hairy test-data-generation needs.


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