Value DescriptionloCaseInsensitive //Key fields and key values are matched without regard to case.
loPartialKey//Key values can include only part of the matching key field value; for example, 'HAM' would match both 'HAMM' and 'HAMMER.'
loPartialKey//Key values can include only part of the matching key field value; for example, 'HAM' would match both 'HAMM' and 'HAMMER.'
const是常量的意思，也就是說這個地方的參數只能給常量，不能是一個變量