0.7% of businesses use Oracle DBA. To help freshmen and experienced candidates ace DBA interviews, we’ve compiled the most common questions and answers in this article.
Thus, Oracle DBA developers can advance their careers with these interview questions.
Let’s start with a basic understanding of the term.
Oracle: What is it?
It is a particular kind of database center that manages and organizes data. In a multi-user system, it enables users to save and retrieve pertinent information so that multiple clients can access the same data simultaneously. Everything is completed while delivering top-notch outcomes.
This article has covered real-time-based and tricky advanced Oracle DBA Interview Questions 2023 to assist you in landing your dream job as an Oracle DBA Developer and passing your interview.
Oracle DBA Interview Questions and Answers:
- Beginners (2–3 years of experience)
- Experienced (5-7 years of experience)
- Advanced Level (10+ years of experience)
Beginners (2–3 years of experience)
What are ORDBMS’s benefits?
You can save the items themselves in the database. You can replace the DBMS language with an OOP language. Even the language used in the program could be the same, so the developer wouldn’t need to make two versions of his objects.
What is a trace file, and how do you make one?
For each server and backend process, it is possible to make a trace file. When a process or user process finds a bug, it sends information about it to its trace. The database can be tweaked with this information.
How can an Oracle database be shut down in various ways?
Normal: With this option, you can’t make any new connections, and the database is shut down when all sessions end.
Immediate: No new connections are allowed, and all operations that are already going on are returned.
Transactional: You can’t make any new connections, and Oracle will wait until all of the current processes are done.
Abort: This happens right away, but the database is not shut down completely. When the database is turned back on, it will need to do a quick recovery. This is not something we can use in normal life.
What are the parts of a logical data model, and how are they different from a physical data model?
A logical data model is made up of the following parts:
Entity: An entity is a type of object that stores information. It has a table with it.
Attribute: This shows what we know about the thing we’re looking at. It is written down as a table column with a certain type of data attached to it.
Record: A record is a group of all the properties of an object for a single condition, shown as a single row in a table.
Domain: A property’s domain is the set of all of its possible uses.
Relationship: This object shows the relationship between two other things.
What’s the point of binding variables?
Bind variables are important because most database providers offer an execution plan cache that stores SQL statements and planning processes that have recently been run and can be used again.
What makes a database different from an instance?
Database files are the physical files that store the data and information that make up a database. There are the control files, the data files, and the redo log files.
In contrast, a shared instance is the storage that all threads and background processes can access.
Also Read: How to Transform Your Data into Stunning Visuals with Matplotlib
Experienced Oracle DBA questions (5-7 years of experience)
How does the “Database Writer” program work?
There can be more than one database process running in the background. “DBWn” is what the operating system calls them. This process is in charge of writing buffers that are “dirty” to the disk. When a server process wants to change a data block, it reads the block from the disk into the buffer cache if it isn’t already there. The copy in the cache is then changed. A “dirty” block is the part of the database in the buffer cache that has been changed.
What does the word “table” mean in Oracle?
The first level of the physical unit in a database is the table. Oracle stores data in rows and columns in rows and columns of a database table. The first level of the physical unit in a database is the table.
How do tablespace and datafiles relate to each other?
Each tablespace is made up of one or more data files, and each database has at least one tablespace.
How can the materialized view be used?
Materialized views are objects with smaller sets of information from base tables that have been summed up, grouped together, or aggregated. They are usually used in data warehouses or systems that help people make decisions.
What do you mean by “view,” and what are the different kinds of views?
Each view has a query that enables you to find particular rows and columns in the view, which is a sort of virtual table. Views can be read-write or read-only.
Advanced Level (10+ years of experience)
What are the advantages of the control file?
The control file must be available for writing by the Oracle database server whenever the database is open. Without the control file, the database cannot be mounted, and recovery is difficult. You might also need to create control files if you want to change particular settings in them.
What does “do a transaction” mean?
Oracle can handle transactions, according to the SQL standard. Oracle treats a group of SQL statements as a single unit of work. This is called a transaction. As soon as you connect to the database, a transaction begins. Once the transaction starts, every SQL DML (Data Manipulation Language) statement you issue after that is part of this transaction. The transaction ends when you disconnect from the database or use the COMMIT or ROLLBACK commands.
What’s the difference between “dropping a table,” “truncating a table,” and “deleting all records” from a table?
- When you delete a table, you also delete its invalid indexes. Both the table definition and the records are thrown away.
- “Truncating” means that bad data values are thrown away automatically.
- Inside the table, the database marks it as empty, and the records that were removed are not written to the transaction log.
When you delete all records, the information is saved in a file called a transaction log.
What does the term “group by” mean?
The GROUP BY keyword is an aggregate function, like SUM or MULTIPLE. Without this function, you can’t figure out the sum of each group value.
What benefits does the control file have?
When the database is open, the Oracle database server needs to be able to write to the control file. Without the control file, you can’t mount the database, and it’s hard to get it back. If you want to change certain settings in the control files, you might also need to make control files.
What is the redo log’s main purpose?
The main job of the redo log is to keep track of all changes made to the database as they happen.
Conclusion
Oracle Database is widely recognized as one of the best database management systems. The majority of businesses use Oracle, which has emerged as one of the most crucial databases in the business world. Being one of the Oracle database administrators is therefore always a professional accomplishment for that individual.
