Interview Questions

Explain about data and how do you store data?

  • Data is any value which we store for future reference. There are different types of data tools which we can use to store data. The simplest data storage tools are notepad, MS-Excel, MS-Access etc.

How data storage is different from data representation?

  • Data storage can be done by using any data tools. Data storage defines how data is stored. On the other hand, data representation is how data is displayed to a user. For example, we can store data in the form of table but represent it in the form of charts!

As a DBA, explain what is a database?

  • Database is a software which allows applications to store and retrieve data faster. It allows companies to create a three tier system where first tier is users, second is application and third tier is database.

Can you differentiate Instance and Database?

  • In Oracle, Instance and database are two separate components but work together. Instance resides on RAM and it is the way users speak to database. The user data resides inside data files which reside on Hard Disks. Users connect to database instance and ultimately instance speaks with database.
  • Instance can also be defined as combination of memory structures and background processes.

How LRU algorithm impacts database instance?

  • RAM works on LRU algorithm. As the database instance resides on RAM, it has to follow same rules as RAM. Hence, Oracle instance also follow LRU algorithm.