sql - Having placeholder columns when creating new database table -


is practice add placeholder columns when creating database table millions of rows, in case schema gets changed later? more efficient rename column insert new one?

there many problems adding "placeholder" columns table.

  • these columns may take useless space, , appear "sloppy".
  • you may create many columns now, , have columns never used.
  • you may not create enough columns now, , have end creating more anyways.
  • you don't know column data types @ time.

always remember if column needs added @ later date , not used of current rows in table, can still keep table normalized creating smaller table holds information, link them using primary key.

let me know if have questions this. hope helps!


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