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for >99% of students, their year group will change every September (going up +1). That suggests an alternative approach: instead of storing "year group", it may be better to store a "cohort identifier" (e.g. nominal intake year, or a September-based birth year) and map that to the year group. In September, the mapping base changes, ...


"Generic database" a.k.a. column-oriented This is a comment, not an answer. A cursory read of column-oriented sounds like what we called a generic DB. We built and maintained a generic database using MS/SQL. Note: I don't recall that performance was a particular issue... Verbose queries - even the simplest, practical useful queries needed 2 or ...


Is it expected that an object's isCompound could change after it's constructed? I think that member ought to be const - or better still, use an intermediate class: class CompoundDataType : public BaseDataType I don't see where this value is ever used, so perhaps it could be removed entirely? The empty destructor can be explicitly defaulted: virtual ~...


Here is one way to avoid hitting table 2 twice: select tmp.* from ( select id, phone1 as phone_num, date from table_1 union all select id, phone2 as phone_num, date from table_1 ) tmp left join table_2 t2 on phone_num in (t2.phone1, t2.phone2) where is null

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