Dynamodb Interview Questions

Dynamodb Interview Questions Download Dynamodb Interview Questions PDF

Dynamodb Interview Questions

For an operation to be completed on an item, you have to specify a condition.
You can define a ConditionExpression that can be constructed from the following:
  • Boolean functions: ATTRIBUTE_EXIST, CONTAINS, and BEGINS_WITH
  • Comparison operators: =, <>, <, >, <=, >=, BETWEEN, and IN
  • Logical operators: NOT, AND, and OR. 

You can also construct a free-form conditional expression that combines multiple conditional clauses which also includes nested clauses.

Projections are the set of attributes that are copied or projected from the table to an index.

They are in addition to the index key attributes and primary key attributes which are automatically projected.

Whenever you define a local secondary index, it is required to specify the attributes that are projected into the index.

Each index consists of a minimum of 3 attributes, and they are:

  • Table partition key value
  • Attribute to serve as the index sort key
  • Table sort key value
An index with a different partition and partition-and-sort key from those on the table is called global Secondary index.
It is considered to be “global” in the sense that queries on the index can span all the items in a table across, all the partitions.
It is the entry point to DynamoDB.The DynamoDB Mapper class provides access to a DynamoDB endpoint and enables the user to access to their data in various tables, execute queries and scan against tables, and perform CRUD operations on items.
Each table can constitute up to five local secondary indexes.
It is a database service that provides and supports storing, updating and querying the objects that are identified using key and values that constitutes the actual content that is being stored.
Here is the list of some of the benefits of using Amazon DynamoDB:
  • It is a managed service where there is no need to hire the experts or worry about installation, setup, cluster etc.,
  • It is scalable.
  • It provides the users high throughput at very low latency.
  • It is durable and highly available.
  • It is flexible and allows dynamic tables creation that includes multi-valued attributes.
  • It is cost-effective.
You are allowed to create a maximum of 5 global secondary indexes per table.
It is a NoSQL database service which is superintended and provides fast and inevitable performance with seamless scalability.
It also enables the users to offload the operating and scaling distributed databases to AWS.
So that the users don’t have to worry about setup and configuration, hardware provisions, replication, throughput capacity planning, cluster scaling or software patching.
  • CreateTable
  • UpdateTable
  • DeleteTable
  • DescribeTable
  • ListTables
  • PutItem
  • BatchWriteItem
  • UpdateItem
  • DeleteItem
  • GetItem
  • BatchGetItem.
  • Query
  • Scan