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What is the proper syntax to get() entries where the sort key begins with a substring using AWS.DynamoDB.DocumentClient in NodeJS?

What is the proper syntax to query database entries whose sort key starts with a specific string?
I believe it's something along the lines of
const query_params = {
TableName: 'my_table',
Key: {
my_primary_key: 'a_primary_key_value',
},
FilterExpression: "my_sort_key begins_with :string",
ExpressionAttributeValues: {
":string": "starts_with_substring"
}
};
Followed by a dynamoDb.get(query_params, ..., but that is not quite right. I am getting an ValidationException: The provided key element does not match the schema error.

According to the SDK query documentation, your query params should look like this
{
TableName: "my-table",
KeyConditionExpression: "#pk= :pk And begins_with(#sk, :sk)",
ExpressionAttributeValues: {
":pk": "a_primary_key_value",
":sk": "starts_with_substring"
},
ExpressionAttributeNames: {
"#pk": "my_primary_key",
"#sk": "my_sort_key"
}
}
You'll also need to change dynamoDb.get() to dynamoDb.query().

mongoDB - Regex search against partial field values

I've a collection of countries with country calling code in the country object. How can I find a country using calling code with a mobile number?
const countries = [
{
name: 'UAE',
callingCode: 971
},
{
name: 'USA',
callingCode: 1
},
{
name: 'UK',
callingCode: 44
}
];
const number = '971524500000'; // Input
How can I find country for the given mobile using regex in mongoose javascript;

[https://en.wikipedia.org/wiki/List_of_country_calling_codes][1]
Take a look at the link above on country calling codes, and specifically see the section "Tree List".
One solution would be to implement a schema in Mongo based on this tree in order to decode the country codes.
So, a table could be created to store Mongo documents containing a field "1x" "2x" "21x" etc (the Y axis in the Tree List table).
Each of these documents could contain an array of sub-documents from x=0 to x=9 (the x axis in the Tree List table). The sub-document can contain the country name/code you are looking for. You can use a direct index into the array in the Mongo document for an efficient lookup.
I think you'll find this to be a pretty efficient implementation and should cover all the bases.

If you can restructure your array to an object this would be the fastest
const countries =
{
971: 'UAE',
1: 'USA',
44: 'UK',
}
;
var code = 44;
console.log(countries[code]);
const countries = [
{
name: 'UAE',
callingCode: 971
},
{
name: 'USA',
callingCode: 1
},
{
name: 'UK',
callingCode: 44
}
];
var myFound =countries.filter(myFunc.bind(this,44));
function myFunc(code,element) {
if(element.callingCode == code){
return element;
}
}
console.log(myFound);

On MongoDB v 4.2 - you can use $let & $regexFind to do this :
db.collection.aggregate([
{
$match: {
$expr: {
$eq: [
{
$let: {
vars: {
value: {
$regexFind: {
input: "971524500000", // pass in as string
regex: { $toString: "$callingCode" }
}
}
},
in: "$$value.idx",
}
},
0
]
}
}
}
]);
Test : MongoDB-Playground
Explanation :
General Use-case :
In general regex searches - Will have an input which will be sub-string of actual string, Ex.:-
Actual string in DB : 'We can do it in mongo'
Input : mongo (/mongo/ - will work)
Your Use-case :
From above case as mongo exists in actual string/value of db field then you can get that document, But your case is different :
Actual string in DB : mongo
Input : 'We can do it in mongo'
This doesn't work that way, So using normal /We can do it in mongo/ isn't going help you here (Also doing few tricks with regex). So we need to make a trick to $regexFind operator. Unlike mongo documentation we need take 971524500000 into input field & regex as string value of callingCode field which is vice-versa to what's given in documentation.
So once we do that, We would get something like below :
{
"match" : "971", /** value of callingCode field */
"idx" : 0, /** Index of `971` in '971524500000' */
"captures" : []
},{
"match" : "1",
"idx" : 2,
"captures" : []
},
null /** 3rd doc no match */
As country code has to be at first of given number we need docs where "idx" : 0 - So we're using $let to get index of returned object & checking against 0 & eventually getting respective docs using $match.
Note :
There is something you need to look into, Just in case if you've docs like below :
{
"_id": ObjectId("5e8f67091aa1cc3d2158ade1"),
"name": "USA",
"callingCode": 1.0
},
{
"_id": ObjectId("5e8f67091aa1cc3d2158ade3"),
"name": "somecountry",
"callingCode": 197.0
}
& input is 1971524500000, then this query will bring both docs in result. This will be the case you need to check on. Anyhow I would suggest to try this query, rather than getting all documents for collection to the code & extract required o/p this might be better to do.

DynamoDB Update ExpressionAttributeValues

Sample test data:
"suppliers" : [
{
"supplierName": "xxx supplier"
},
{
"supplierName": "zzz supplier"
}
]
Excerpt of UpdateItem Params:
ExpressionAttributeValues:{
":sA" : {L: [event.suppliers]}
// ":sA" : {L: event.suppliers}
}
I encounter "UnexpectedParameter: Unexpected key '0' found in params". I tried changing the formatting of the AttributeValues but I get other errors like "UnexpectedParameter: Unexpected key 'supplierName' found in params".
I need help properly defining a list AttributeValue. Note that the input sample test data may contain x number of supplierName objects and hence defining the keys (ie. '0', '1', etc) in the AttributeValue is also not an option. I also prefer not to use the documentClient version of UpdateItem.

ExpressionAttributeValues is about to set a value to the parameter of the update expression, for example:
dynamoDb.update({
TableName: ...,
Key: ...,
UpdateExpression: 'set suppliers = :suppliers',
ExpressionAttributeValues: {':suppliers': event.suppliers}
}
You have to provide the key to the record and then you can change the suppliers attribute.

DynamoDB FilterExpression with multiple condition javascript

I have a table with partition key and sort key also 2 other columns. I am unable to get items using FilterExpression for multiple conditions with AND in DynamoDB using javaScript AWS SDK. Can anyone provide correct code to retrieve data with multiple conditions in FilterExpression?
My code is as follows:
var params = {
TableName: 'Department',
KeyConditionExpression: '#company = :companyId'
, ExpressionAttributeNames: {
'#company': 'CompanyID',
'#dType': 'DepartmentType',
'#cTime': 'CreatedTime'
}
, ExpressionAttributeValues: {
':companyId': 'Test',
':deptType': dType,
':daysPrior': 1250456879634
},FilterExpression: '#dType = :deptType AND #ts > :daysPrior'
};

There is typo error in the format in your query(after CreatedTime)
To keep it clean, use either double quotes or single quotes but not both.
I have used double quotes, just the way aws sample codes are there.
var params = {
TableName: "Department",
KeyConditionExpression: "#company = :companyId",
ExpressionAttributeNames: {
"#company": "CompanyID",
"#dType": "DepartmentType",
"#cTime": "CreatedTime" //here
},
ExpressionAttributeValues: {
":companyId": "Test",
":deptType": dType,
":daysPrior": 1250456879634
},
FilterExpression: "#dType = :deptType AND #cTime > :daysPrior"
};

In case you need a bit more complex filter expressions to scan or query your DynamoDB table, you could use brackets, for example:
var params = {
TableName: "Department",
...
FilterExpression: "(not (#type <> :type and #company = :company)) or (#timestamp > :timestamp)",
...
};
Note: this example filter expression does not have a particular meaning.

Querying DynamoDB with node.js between values

Querying dynamoDB table with node.js. The DynamoDB table has key of Timestamp, represented by an integer. In this case, I left :timestampStart as 1 and timestampEnd as 10 as an example.
var params = {
TableName: "Table2",
KeyConditionExpression:"Timestamp = :ts BETWEEN :timestampStart AND :timestampEnd",
ExpressionAttributeValues: {
":ts":"Timestamp",
":timestampStart": 1,
":timestampEnd": 10
}
};
The :ts is not correct, I can see this. I want to return any rows found with a Timestamp value between timestampStart and timestampEnd.
Error message:
"errorMessage": "Invalid KeyConditionExpression: Syntax error;
token: \"BETWEEN\", near: \":ts BETWEEN :timestampStart\"",

If Timestamp is the partition key and not the sort key. Then, you have two problems:
In a Query operation, you cannot perform a comparison test (<, >, BETWEEN, ...) on the partition key. The condition must perform an equality test (=) on a single partition key value and, optionally, one of several comparison tests on a single sort key value. For example:
KeyConditionExpression: 'HashKey = :hkey and RangeKey > :rkey'
You have a syntax error in your KeyConditionExpression, obviously. Keep in mind that Timestamp is a reserved word in DynamoDB. So, you'll have to use ExpressionAttributeNames for that:
(Assuming you have an Id partition key and Timestamp sort key)
var params = {
TableName: "Table2",
KeyConditionExpression: "Id = :id AND #DocTimestamp BETWEEN :start AND :end",
ExpressionAttributeNames: {
'#DocTimestamp': 'Timestamp'
},
ExpressionAttributeValues: {
":id": "SOME VALUE",
":start": 1,
":end": 10
}
};