For the freshers who’ve just completed their Oracle 11G database certification and appearing for interviews, there are a few fundamental questions to expect. A large number of interviewers are of the opinion that database freshers are so engrossed in preparing for the complex questions that they tend to goof up the basics.
So here are five of the fundamental and most common database questions that are asked in 11G interviews. This should help you recapitulate the database fundamentals you learnt.
5 Fundamental Yet Important 11G Interview Questions
Databases offer single points of mechanism to store and retrieve information using tables. These tables, which store information about entities and attributes and the relation among them, comprise of rows and columns, where specific attributes are listed in the columns and the corresponding attribute values in the rows. Such tables also store index and attributes data types. Popular Database Management Systems include Oracle, Microsoft Access, Microsoft SQL Sever, etc.
What are the different storage systems available and which of them does Oracle use?
There are basically two kinds of storage systems available, namely:
RDBMS - Relational Database Management System
HSM - Hierarchical Storage Management System
Most of the databases use the RDBMS model and even Oracle uses the same.
What is join methods? How many types of join methods exist?
The join method refers to the link that joins one thread to another after the previous one has run its course. There are three types of join methods, namely:
Hash join, which uses the hash algorithm first in the smaller table followed by bigger ones to make joined columns. Matching rows are returned after that.
Then it join, which connects inner tables with their respective set of results.
Nested loop join, which gets results after applying filter conditions that are based on the outer tables.
Merge join are used to sort tables and then merge the sorted rows.
How is logical data different from physical data model? Name the components of logical data model.
Logical data models refers to databases that deal with logical objects like relationships and entities while physical data models deal with physical objects such as constraints and tables.
Components of logical data model include:
Define normalization. Name the different forms of the same.
Normalization refers to the process of organizing tables and fields of a relational database, so as to minimize dependency and redundancy. It ensures consistency of data and saves storage space.
First Normalization form when all domains only contain automatic values.
Second Normalization form when the domain is in the first normalization form and all non-key attributes are functionally and fully dependent on the primary key.
Third Normalization form, when the domain is in the second Normalization form and all non-key attributes are dependent on the primary key in a non-transitive manner.
Fourth Normalization form
Fifth Normalization form
If you’ve undertaken any of the following Oracle training courses, you’d have notes to revise all of the above and more:
Oracle 12c training
Oracle 10g training
Oracle 11g DBA training
Have more 11G interview questions to share? Post them in the comments below; we’d love to hear from you as well.