What's the better database design: more tables or more columns? -

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a former coworker insisted database more tables fewer columns each better 1 fewer tables more columns each. example rather customer table name, address, city, state, zip, etc. columns, have name table, address table, city table, etc.

he argued design more efficient , flexible. perhaps more flexible, not qualified comment on efficiency. if more efficient, think gains may outweighed added complexity.

so, there significant benefits more tables fewer columns on fewer tables more columns?

i have few simple rules of thumb follow when designing databases, think can used make decisions this....

  1. favor normalization. denormalization form of optimization, requisite tradeoffs, , such should approached yagni attitude.
  2. make sure client code referencing database decoupled enough schema reworking doesn't necessitate major redesign of client(s).
  3. don't afraid denormalize when provides clear benefit performance or query complexity.
  4. use views or downstream tables implement denormalization rather denormalizing core of schema, when data volume , usage scenarios allow it.

the usual result of these rules initial design favor tables on columns, focus on eliminating redundancy. project progresses , denormalization points identified, overall structure evolve toward balance compromises limited redundancy , column proliferation in exchange other valuable benefits.


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