c++ - Deriving from templatized base class -

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i've buil small database of different kinds type of objects. idea have base templatized class, let's call database , let derive other classes that.

for example:

template< typename record,           size_t record_size,           char record_sep = '!',           char record_param_sep = ',',           char record_field_sep = '~',           size_t max_records_per_query = 5000,           size_t min_record_count = 15000           > class database { public:     typedef record record_t;     typedef std::vector< unsigned char > querybuffer;     database( const std::string& basepath, const std::string& recordpath, const std::string tablefilename );      enum class queryresult     {         ok,         no_data,         overflow,         future_date,         future_range,         error     };      void add( void add( const record_t& r )     {         lock lock( mmutex );         // ... lots of stuff here     }      queryresult query(querybuffer &qb, time_t first, time_t last )     {         lock lock( mmutex );          // ... lots of stuff here     }      queryresult query(querybuffer &qb, time_t first )     {         lock lock( mmutex );          // ... lots of stuff here     }      // protected , private data };

then derive class in way

class gamedatabase : public database< gametype, 9 > { private:     using mybase database< gametype, 9 >;  public:     gamedatabase( const std::string& basepath )         : mybase{ basepath, "g/", "g.dat" }     {     }      // query method     queryresult query(querybuffer &qb, size_t first, size_t last )     {         lock lock( mmutex );          // use protected methods of mybase          // .... lots of stuff here           } };

is idea or better solution? problem definition of database must inlined, , long code.

it's not unusual idiom, ordinarily template parameters either types, or integers need compile-time. hoping gain compiling sizes , delimiters in that?

i suggest make them members of database, initialized in constructor. if want inline everything, go right ahead. don't make things template parameters when need them const.


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