NCR Corporation Software Engineer Interview Questions and Answers

I was asked to write SQL queries for data retrieval, aggregation, and manipulation during the interview.

• Write a query to select all columns from a table: `SELECT * FROM employees;`

• Create a query to count the number of records: `SELECT COUNT(*) FROM orders;`

• Join two tables to retrieve related data: `SELECT a.name, b.order_date FROM customers a JOIN orders b ON a.id = b.customer_id;`

• Use a WHERE clause to filter resu...read more

Tree traversal methods: inorder, preorder, and postorder are essential for accessing nodes in a binary tree.

• Inorder Traversal: Visit left subtree, root, then right subtree. Example: For tree 1,2,3, output is 2,1,3.

• Preorder Traversal: Visit root, left subtree, then right subtree. Example: For tree 1,2,3, output is 1,2,3.

• Postorder Traversal: Visit left subtree, right subtree, then root. Example: For tree 1,2,3, outp...read more

Spring Sleuth is a distributed tracing system for microservices built on top of Spring Cloud.

• Spring Sleuth helps in tracking and monitoring requests as they travel through different microservices.

• It generates unique trace and span IDs for each request to help in correlating logs and metrics.

• Spring Sleuth integrates with Zipkin, a distributed tracing system, to provide visualization of request flows.

• It is commonly ...read more

Redux is a predictable state container for JavaScript apps.

• Redux is a state management library commonly used with React.

• It helps in managing the state of an application in a predictable way.

• Redux follows a unidirectional data flow architecture.

• Actions are dispatched to update the state through reducers.

• State is stored in a single immutable state tree.

Primary constraints are used to uniquely identify a record while secondary constraints are used to enforce business rules.

• Primary constraints are used to create a unique identifier for a record in a table

• Primary constraints can be used to enforce referential integrity

• Secondary constraints are used to enforce business rules

• Secondary constraints can be used to limit the values that can be entered into a column