DynamoDB检索最后一行[关闭]

Question

i need some help with DynamoDB. I have table as following:

| Shortener (Hash key) | ShortenedURL (Range key) | LongURL      |
|-----------------------------------------------------------------|
| "My webpage url"     | "1"                       | "example.net"|
| "My webpage url"     | "6"                       | "example.com"|
| "My webpage url"     | "4"                       | "example.eu" |

How to retrieve the row with biggest number in "ShortenedURL"? Im totally new to DynamoDB & NoSQL stuff. Using AWS PHP SDK. Tried to search for hours and didnt find anything useful. Everything i tried ended with result like "1" or "4".

Answer 1

To accomplish this, you can Query with the following arguments:

• hashKey is "My webpage url"
• No condition on the rangeKey
• limit is 1 (you only want one thing)
• withScanIndexForward=false (this goes from biggest to smallest)

This will only work if your rangeKey is a Number type. If it's a String, then you can only get lexicographical ordering, so "last" may be weird (these three strings appear in this order: ["1, "10", "2", ...]).