在javascript中查询dynamodb日期范围

Question

If my table looks like this

Hash Key is a number like 7
Range Key is a timestamp like 2017-02-21 17:20:04.010000

and then the payload is something like:

{ "new" : { "N" : "903" }, "number" : { "N" : "7" },
  "Timestamp" : { "S" : "2017-02-21 17:20:04.010000" }, "total" : { "N" : "903" }}

I want to query for all instances where 'number' is 7(s) within a given timestamp range.

what does my params function need to look like? I have looked at some examples online like this one:

var params = {
    TableName: "Movies",
    KeyConditionExpression: "#yr = :yyyy",
    ExpressionAttributeNames: {
        "#yr": "year"
    },
    ExpressionAttributeValues: {
        ":yyyy":1985
    }
};

but not really following what the expressions are doing. Any help or pointing me towards an example is greatly appreciated.

Answer 1

You cannot embed literal values in condition expressions today. That is why you need to define them in ExpressionAttributeValues and use the variable instead. Again, some attribute names would make document paths in condition expressions be invalid. You use the ExpressionAttributeNames for those cases. year seems to be a valid document path even without using path variables, so maybe you do not need ExpressionAttributeNames in this example.