| MiniOB 1
    MiniOB is one mini database, helping developers to learn how database works. | 
成员的完整列表,这些成员属于 ConditionFilter,包括所有继承而来的类成员
| filter(const Record &rec) const =0 | ConditionFilter | pure virtual | 
| ~ConditionFilter() (定义于 ConditionFilter) | ConditionFilter | virtual |