Moving past the monolith, Part 3 – Think about how you share data
This is part of a series of posts about Moving Past The Monolith. To start at the beginning, click here.
In my last post, I talked about how you can separate data within your application. Sooner or later, someone outside your team is going to need to access your data. How are you going to get it to them while maintaining the flexibility that you need to be able to change when you need to?
It’s unlikely that you’re going to be able to go on forever without anyone asking for access to your data. People usually need it for a good reason — your data has a lot of value, so you should be willing to share it. But you want to do it in a controlled manner. Here is my typical thought progression:
- Can I create a schema that contains only views and stored procs that the other application will use?
- If I have to give teams access to tables, can I limit what they have access to? How will I know what they have access to?
- If someone needs to update data, does it really have to be through database calls or can you have them call a web service instead? If a straight data load makes sense, how do you make sure that this doesn’t adversely affect anything else that my application might do?
- If someone asks to have read-only access to the database to write queries, are they doing it just for research purposes or are they going to write application code against those tables?
- If BI or reporting teams want access to the database, can they write their queries in stored procs or views in a specific schema so that you know what they’re touching? (Especially watch out for SSIS packages that have custom SQL in them, it’s extremely difficult to figure out what is in those packages if you didn’t write them, and you won’t know if you’re going to break if you change something.)
- How do I keep track of who has access to my database so that I can notify them when I’m going to make a potentially breaking change? (If you don’t know who has access, this will severely limit you’re ability to change because you will have no idea what you’re going to break.)
- If another team wants to write application code against my data model, can they code against a copy of the data in their database which gets loaded from a batch job instead so that we both can maintain the freedom to change? Does it make sense to get the data from a web service instead?
Other people wanting access to your data is inevitable. How you manage it is up to you, but it’s important that you be proactive about managing everyone who is dependent on your data.
Read the next post in this series, Using the Service Object pattern.