How to make search using "contains" with DynamoDB

Question

I'm trying to make search function on my React app.

I have this DynamoDB table:

---------------------
movie_id | movie_name
---------------------
1        | name a
---------------------
2        | name b
---------------------

I want to make a search function to search "b" on the React app's search input and get "name b" from the DB as the result.

I tried to query with CONTAINS but didn't work and does not seem to be a proper way to do it.

const SEARCH_KEYWORD = "b";

let params = {
   TableName : 'TABLE_NAME',
   KeyConditionExpression: "contains(#movie_name, :movie_name)",
   ExpressionAttributeNames:{
     "#movie_name": 'movie_name'
   },
   ExpressionAttributeValues:{
       ":movie_name": SEARCH_KEYWORD
   }
};
documentClient.query(params, function(err, data) {
  console.log(data);
});

What is the best way to create search function on my React app with DynamoDB?

Does it even make sense to run a query by the search keyword to check if the data contains keyword value?

Solution

The CONTAINS operator is not available in the query API. You need to use the scan API for this (see this link).

Try the following:

const AWS = require('aws-sdk');
const documentClient = new AWS.DynamoDB.DocumentClient();
const SEARCH_KEYWORD = "b";

let params = {
    TableName : 'TABLE_NAME',
    FilterExpression: "contains(#movie_name, :movie_name)",
    ExpressionAttributeNames: {
        "#movie_name": "movie_name",
    },
    ExpressionAttributeValues: {
        ":movie_name": SEARCH_KEYWORD,
    }       
};

documentClient.scan(params, function(err, data) {
    console.log(data);
});

Result:

{ 
    Items: [ 
        { 
            movie_id: 2,
            movie_name: 'name b' 
        } 
    ], 
    Count: 1, 
    ScannedCount: 2 
}

Comments

[Skate to Eat]

Thank you so much! It works! One more question tho, is this ideal way to build search function? or there's better way to do this?

[Zanon]

@Ohsik, searching with "contains" will never be optimal because it will always require a full scan of the table. This can bring to performance issues if you have a lot of data. However, checking if the name "begins with" can be used with the query API and benefit from indexes, which will greatly improves the performance. But obviously "begins with" is different from "contains".

[Zanon]

@Ohsik, if you need to use "contains" with millions of rows, I suggest that you look after Elasticsearch integration with DynamoDB.

[user3277530]

I think that it is possible now

[user3277530]

you can use it as a filter expression now

[lopezdp]

Limitation here is that it will only scan through 1mb of data at a time... :(

[theboshy]

how can this be applied to a list of objects instead of a list of plain strings?