Storing boolean values: bundle or individually?

I have about 50 discrete boolean values that I need to store in the database. These are logged every few seconds so I will be storing a lot of them over time.

The way this data would be used is: 1) Access a bulk of time to see flag status history 2) Find times at which flag changed status

Once stor开发者_Go百科ed, the records will not be updated.

Would you recommend storing each value in its own column, or bundling them in an integer values and storing in a few columns?

I am mostly curious about which approach would be better for storing/accessing data as it gets bigger? Eventually I will be getting data from multiple units 24/7, so there will be a lot of data, so I guess my question is: is there a performance/stability tradeoff between packed integers and individual columns.

I am using MySQL with VB.NET and PHP interfaces to it, but the question is more of a generic database design rather than mysql-specific.

Thank you,

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These kind of facts rarely remain boolean as the application evolves.

Today they're True/False.

Tomorrow they're True/False/NA/Don't Know

The next day they become an integer.

Eventually, they become proper "conditions" based on other pieces of data.

Don't "pack" them 32 to the integer. That's short-sighted. Leave them as independent columns -- perhaps "bytes" or something smallish.

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Even if you know that they will always be a bool, it is still better to have them in a separate column. This will make queries much easier and faster in the future. If you have to do bit unpacking for a query, you'll regret it. I also echo what S.Lott said. Prepare for the future (for example, what if you can't get the status for some reason? Will you say false or unknown?)