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转于:https://blog.csdn.net/claram/article/details/77574600 首先明确:为什么要用联合索引? 对于查询语句“SELECT E.* FROM E WHERE E.e1=1 AND E.e3=2”涉及到两列,这个时候我们一般采用一个联合索引(e1, e 阅读全文
摘要:
package ReflectTest; public class Dog { private final String name; private final int sex; private final int weight; private final String type; public Dog(String name, int sex, ... 阅读全文