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It's not always straight forward. A lot of protocols use delta encoding. For example "insert BUY GBPUSD, price=1.1702, volume=100000". But yes, it's worth comin

• naasking 10y ago
  But then you can't query schemaless data without sophisticated parsing or absurd wildcard/regex matching of some sort, which obviously is highly error-prone, thus making schemaless data at best only probabilistically useful. For delta-encoded models, it still seems straightforward to define a general schema via (operation, objectId, value, transactionId) tuples. 'value' can be a string if you want maximum flexibility, but at least this way you can reliably query the operations, entities involved and which changes happened together as a group.
  • fnord123 10y ago
    >But then [it sucks] Absolutely. I agree with you, I'm just saying it's not trivial to turn a delta encoded format into a nice schema. I mean, I would advise against storing deltas as tuples and considering that the schema. If it's at all possible, try to rectangularize your format. If you're using a column store a lot of the redundant data from the denormalisation can be compressed away. If the rectangularisation is lossy then you may need to archive the raw data. This is the hurdle where a lot of people stop and choose schema-on-read since they can't afford the storage requirements for an archive of raw data and a nice analytic format for querying.