>I was called in to consult on a database problem and they did the same but with XML. It was really bad, and bad for performance and comprehension.
I can see XML being really bad for performance, but given that json column data is handled like native data in modern databases (and you can index/query on fields in the json, which pretty much negates the performance impact), using a json/jsonb column is actually a decent guide.
You are spot on in picking me up on this, thanks. It needs clarification. xml/json is neither right nor wrong, it depends. Performance, well, it depends. What is unquestionably wrong is the poster's advice "When in doubt, just have a column full of JSON and figure it out later".
Pouring structurable data into an unstructured heap is just laziness and will hurt you later. I've seen the cost of deciding to 'leave it for later' - it's high! I've been involved in cleaning it up. It's horrible.
Years ago I picked up a book written in the 1960s (so pre IT)for secretaries, and it had a beautiful line in it "the filing cabinet is a place where you find things, not lose them". Still applies. Always will do.
> "the filing cabinet is a place where you find things, not lose them"
"Those who cannot remember the past are condemned to repeat it." - Santayana
“Explanations exist; they have existed for all time; there is always a well-known solution to every human problem—neat, plausible, and wrong.” - Mencken
Software project management is full of thin and runny rationalizations...I (HHOS) include this form under the heading of "Data Abnormalization"...
I've had a lot of experience. You can learn from it or not. If not, feel free to prove Santayana right again, and at great personal cost :) In fact, I encourage you to!
Is there a reason then not to use a single column with JSON? The columns would then be "virtual" (the column jsondata would spawn a column jsondata.firstname etc.)
This question is your of pure curiosity, I do not deal with databases so I hopefully correctly understood your comment.
I can see XML being really bad for performance, but given that json column data is handled like native data in modern databases (and you can index/query on fields in the json, which pretty much negates the performance impact), using a json/jsonb column is actually a decent guide.