权限往往是一个极其复杂的问题，但也可简单表述为这样的逻辑表达式：判断“Who对What(Which)进行How的操作”的逻辑表达式是否为真-Permission is often a very complex issue, but this can be simply described as the logical expression: to determine " Who to the What (Which) to How the operation" of the l