java - Future Proofing SQL table? -


i considering creating mysql data base non-mission critical project. thinking scenario when, in case had insert column in table, how can achieve without compromising data integrity of pre-existing columns specify default values of additional columns? i'd answer both sql , java persistence api (jpa).

in addition, i'd know how add table within cell of parent table.

the addition of column should have no effect on pre-existing data, unless links columns, such creating multi-column index, unique key, or similar. if there no such linkages between new & old columns, add many columns like. go crazy!


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