20 Oracle Architecture Interview Questions and Answers

Oracle Architecture is the underlying structure of the Oracle Database. It is important for any software developer or database administrator to have a strong understanding of the Oracle Architecture in order to properly manage and maintain the database. When interviewing for a position that requires knowledge of Oracle Architecture, you can expect to be asked a variety of questions about the topic. In this article, we will review some of the most common Oracle Architecture interview questions and provide tips on how to answer them.

Oracle Architecture Interview Questions and Answers

Here are 20 commonly asked Oracle Architecture interview questions and answers to prepare you for your interview:

1. What is Oracle?

Oracle is a relational database management system (RDBMS) that is used to store, retrieve, and manipulate data. Oracle is a powerful and versatile system that can be used for a variety of purposes, from small businesses to large enterprises.

2. What are the different types of databases that can be created using Oracle?

The three types of databases that can be created using Oracle are:

1. Standard Database: A standard database is the most common type of database and is used for general purpose data storage.
2. Container Database: A container database is a type of database that can contain multiple databases, each with its own tables and data.
3. Pluggable Database: A pluggable database is a type of database that can be plugged into a container database.

3. Can you explain what a tablespace is in context with Oracle?

A tablespace is a logical container for segments (tables, indexes, etc.). All data in an Oracle database is stored in tablespaces. Tablespaces can be created when the database is created or they can be added later.

4. What’s the difference between an instance and database in Oracle?

An instance is a running copy of Oracle that consists of memory structures and background processes. A database is a collection of datafiles, redo log files, and control files.

5. What is an SGA?

The SGA is the System Global Area in an Oracle database. It is a shared memory region that is used by the Oracle instance to store data and control information. The SGA is divided into a number of subcomponents, each of which serves a different purpose.

6. How does data get stored on disk when you create a new table in Oracle?

When you create a new table in Oracle, the data for that table is stored in a datafile. The datafile is a binary file that contains the actual data for the table. The datafile is then stored on disk.

7. What do you understand about redo logs?

Redo logs are used in Oracle to track changes made to the database. They are used in conjunction with the undo logs to provide a complete picture of the changes made to the database. Redo logs are used to recover the database in the event of a failure, and they are also used to replicate the database to other servers.

8. What do you understand about control files?

A control file is a small binary file in an Oracle database that contains information about the physical structure of the database. This information includes the location of datafiles and redo log files, the time stamp of the database creation, and the database name. The control file is used by the Oracle instance to open and mount the database.

9. What is the function of a buffer cache?

The buffer cache is a section of memory where data from disk is read into and stored. When a process needs to read data from disk, it first checks the buffer cache to see if the data is already present. If it is, the data can be read from the cache instead of from disk, which is much faster.

10. What is the purpose of PCTFREE parameter in Oracle?

The PCTFREE parameter in Oracle is used to specify the minimum percentage of free space that must be available in a data block before Oracle can insert a new row into that block. This parameter is used to help prevent data blocks from becoming too full, which can lead to performance issues.

11. What is the importance of EXTENT ALLOCATION POLICY?

The EXTENT ALLOCATION POLICY is an important part of the Oracle architecture because it dictates how space is allocated within an Oracle database. This policy can have a big impact on performance, so it is important to understand how it works.

12. What is a data block?

A data block is the smallest unit of storage in an Oracle database. A data block contains the data for a single row of a database table.

13. What is the main use of the SYSTEM tablespace?

The SYSTEM tablespace is used to store the data dictionary for the entire database. The data dictionary contains information about all of the objects in the database, as well as the relationships between those objects.

14. Are there any limitations to creating indexes on views? If yes, then what are they?

Yes, there are some limitations to creating indexes on views. One such limitation is that the view must not be based on another view that already has an index. Additionally, the view must not be based on a table that has a column with a data type of LONG, CLOB, or BLOB.

15. What is a functional dependency?

A functional dependency is a relationship between two sets of data in a database. In Oracle, a functional dependency exists when one column in a table uniquely determines the value of another column in the same table.

16. Why is normalization important for relational databases?

Normalization is important for relational databases because it helps to reduce data redundancy and improve data integrity. When data is stored in a normalized form, it is easier to update and maintain, and there is less risk of data corruption.

17. What is the significance of having multiple Indexes per table?

There can be multiple indexes per table in Oracle for multiple purposes. For example, a table might have a primary key index to enforce uniqueness, and then a separate index on a column that is frequently searched. Having multiple indexes can help improve performance by allowing the database to more quickly find the data it needs.

18. How would you define an ACID property?

The ACID property is a set of database transaction properties that ensure data integrity and consistency. The acronym stands for Atomicity, Consistency, Isolation, and Durability.

19. What is a checkpoint?

A checkpoint is a point in time at which all redo information up to that point is written to the online redo logs. This ensures that, in the event of a failure, the database can be recovered up to the last checkpoint.

20. What is a transaction log?

A transaction log is a file that is used to store information about all of the transactions that have been performed on a database. This information can be used to roll back changes, or to recover data in the event of a failure.