投影产生的服务会指定被投影的企业(而不是被查询的企业)的businesskey(企业键值)。
Services which are projected will specify the businesskey of the business they are projected from, rather than the business being queried.
通过指定一个投影我们指定的剪裁或观察的体积。
By specifying a projection we specify the clipping or viewing volume.
在给定关系上指定该关系属性的一个投影产生只包含那些属性的且重复项全已取走的第二个关系。
A projection on a given relation, specifying attributes of that relation, produces a second relation containing only those attributes with all duplicates removed.
应用推荐