The fundamental constraint for mobile devices is limitations because of energy supply and bandwidth.
能量供应和带宽的限制成为制约移动设备的基本因素。
2
Because the SchemaFactory is tied to a specific constraint model, you must supply this value at factory construction.
因为SchemaFactory是与具体的约束模型联系在一起的，所以必须在工厂构造的时候提供这个值。
3
A workaround to this is to supply a default value to the not NULL column whose value comes from a BEFORE INSERT TRIGGER, so that the constraint is not violated.