首先使用实体框架代码继承，在表中重复字段

Class GeneralRequest 
{    
String BaseProperty { get set}
}

RapidRequest: GeneralRequest
{
Bool IsSignRequired { get set}    
}

BackRequest : GeneralRequest
{
Bool IsSignRequired { get set}    
}

OtherRequest: GeneralRequest
{   
String Note   { get set}   
}
Class GeneralRequest 
{    
String BaseProperty