Alex Jeffreys

20 June 2018

8 Comments

Database subsetting. What it is, what it’s for, and why we’d love to hear from you.

We’re looking into database subsetting, and if you need it or are investigating it, we want to hear from you. Please share your thoughts in the comment section below.

What is database subsetting?

Database subsetting is creating a copy of a database that contains only a portion of the data, while still being referentially intact.

For example, suppose you have a table in a database containing millions of customers, but you only want to work with a database that contains thousands. Simple enough, just copy over a fraction of the rows, right?

But then suppose you also have an orders table that contains references to the customers. You’ll need to take only those orders that are related to customers in your sample. As your schema grows more complicated, so does the process of taking a valid subset of the data, and the need for automating the process becomes greater.

Why would I want a subset of my data?

We think there are many reasons organizations need subsets of data for development work, and right now we’re looking at three use-cases:

• Testing, development and training environments – developers often want to work with real data, but providing a copy of your entire production database would be too costly in time and disk space, especially if you need to provide a copy for each developer. Subsetting allows you to work with data that contains all the necessary links between tables for your programs to function, but for a fraction of the cost.

• Multiple organizations or departments – you may have a database that contains data for a number of different organizations or departments, and providing the whole database would expose data to individuals without the correct permissions. Instead, you can provide a subset containing just the data that is relevant to a particular organization or department.

• Old data – you may want to discard a portion of your data based on some criteria. For example, you might want to clear out data older than a certain date, or data which you can no longer keep in order to comply with regulations like the GDPR.

What do you think?

Do you agree with us? Can you think of any other scenarios where you might need database subsetting? Are there other aspects of the use-cases we’ve outlined that should be considered?

We want to gain a deeper and broader understanding of the demand for data subsetting, so if your business has a need for any of the above or you would be interested in data subsetting for any other reason, please share your thoughts in the comment section below.