Database - Interview Questions and Answers for 'Amd' | Search Interview Question

Database - Interview Questions and Answers for 'Amd' - 3 question(s) found - Order By Newest

Q1. What is the purpose of Commit and Rollback in Databases ?

Ans. When a DML is executed, the changes only stays in session and still not pushed to DB Tables, Commit is used to push those changes to the Tables.

In case we realize that we don't want to commit those changes and would like to ignore them, we can use rollback.

For example - You may like that for a banking transaction you would like to update the account balance only if the debit or credit record was correctly inserted, so you may like to encapsulate both DML's - insert for transaction and update for balance in a single transaction and would only commit if both succeeds else rollback.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve databases commit rollback Asked in 2 Companies Basic}

Related Questions

What is ACID ?

What is database deadlock ? How can we avoid them?

What things you would care about to improve the performance of Application if its identified that its DB communication that needs to be improved ?

If you are given a choice to implement the code to either Insert a Record or Update if already exist, Which approach will you follow ?

What is the use of @GeneratedValue annotation in Hibernate?

What are temp tables ?

What is a Database Trigger ?

What is database Normalization ?

What happens to backups if we delete the RDS instance ?

What is a Cursor ?

Q2. What are the methods to connect to database in Java ?

Database

Ans. JDBC ( Java Database Connectivity ),ODBC (Open Database Connectivity), Hibernate, JPA ( Java Persistence API ), JOOQ,MyBatis

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve database connection jdbc ORM Hibernate Asked in 1 Companies}

Related Questions

What is ACID ?

What is database deadlock ? How can we avoid them?

What things you would care about to improve the performance of Application if its identified that its DB communication that needs to be improved ?

If you are given a choice to implement the code to either Insert a Record or Update if already exist, Which approach will you follow ?

What is the use of @GeneratedValue annotation in Hibernate?

What are temp tables ?

What is a Database Trigger ?

What is database Normalization ?

What happens to backups if we delete the RDS instance ?

What is a Cursor ?

Q3. Write a SQL to delete duplicate records in a table

Database

Ans. DELETE FROM TABLE WHERE ROW_NUM NOT IN ( SELECT MAX(ROW_ID) FROM TABLE GROUP BY DUPLICATE_FIELD )

or

DELETE FROM TABLE a WHERE ROW_ID >(SELECT MIN(ROW_ID FROM TABLE b WHERE a.DUPLICATE_FIELD=b.DUPLICATE_FIELD);

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 3 Companies}

Related Questions

What are Inner , Outer , Left and Right Joins in SQL ?

What is JDBC? Describe the steps needed to execute a SQL query using JDBC.

What are temp tables ?

What is a self Join and give an example of a self Join ?

or

What is self Join and What is it's purpose ?

Do you like Native SQL Apis like JDBC or JPA / Hibernate ?

Is there any schema in mongo DB ?

Difference between Inner and Outer Join ?

What is a Cursor ?

Does SQL allow null values ? Can we use it within Where clause ?

Write an SQL to find all records having all upper case alphanumeric characters in a field ?

Search Interview Questions

Help us and Others Improve. Please let us know the questions asked in any of your previous interview.