Using SimpleDB database With AWS Lambda In NodeJS

Posted By : Ankit Uniyal | 25-Dec-2017

nodejs

In this blog, we will give you a brief description of the SimpleDB database and how to connect with SimpleDB database in NodeJS under AWS Lambda environment.
SimpleDB database is a highly available NoSQL database which stores data in key-value pairs.
Some of the limitations on SimpleDB database :

1.Maximum domain size allowed is to be 10 GB per domain.
2.We can delete maximum 25 attributes in a single operation of the batchDeleteAttributes method of SimpleDB.
3.Maximum 1 billion attributes allowed per domain.
4.Truncate or deleting all attributes operation doesn't provide by SimpleDB domain.

Below are the various methods to query SimpleDB database in NodeJS :

var AWS = require('aws-sdk');

var simpledb = new AWS.SimpleDB({
   endpoint: 'your_endpoint',
   region: 'your_region',
   keyid: 'your_keyid',
   secret: 'your_secret_key'
});

1.To list all the domains in SimpleDB database :

var params = {
      DomainName: 'your_domain_name'
};

simpledb.listDomains(function(error, result, data) {
    if (error) {
        console.log("Error on domain listing is", error);
    } else {
        console.log("Listed domains", result);
    }
});

2.To create a domain in SimpleDB database :

var params = {
    DomainName: 'your_domain_name'
};
simpledb.createDomain(params, function(err, data) {
   if (err) {
       console.log("Error on domain creation is", err);
   } else {
        console.log("Domain created", data);
      }
});

3.Delete SimpleDB domain database :

var params = {
    DomainName: 'your_domain_name'
  };
simpledb.deleteDomain(params, function(err, response) {
    if (err) {
        console.log("Error on getting attributes", err);
    } else {
        console.log("response for deleting domain is", response);
    }
})

4.Select Query in SimpleDB database :

var params = {
      SelectExpression: "select * from 'your_domain_name' where attributeField = 'attributeValue',
      ConsistentRead: true
    };
    simpledb.select(params, function(err,response) {
      if (err) {
         console.log("Error on getting attributes",err);
      } else {
         console.log("response is",response);
      }
});

5.Putting Attributes in SimpleDB database :

var params = {
    Attributes: attributesArray,
    DomainName: 'your_domain_name',
    ItemName: 'item_name'
};

Note :

a. Atttributes field should be an array.

b. If we want to update an existing Attribute value then we can add the below field in params object.

params['Expected'] = {
    Exists: true,
    Name: 'existing_attribute_field',
    Value: 'previous_attribute_field_value'
}

simpledb.putAttributes(params, function(err, data) {
    if (err) {
        console.log("Error on adding attributes", err);
    } else {
        console.log("Attributes added successfully", data);
    }
});

Thanks