Top Data Modeling Interview Questions and Answers

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Here we will examine the most significant data modelling interview questions that will be necessary in the year 2024. If you are interested in a job in database management systems, they would be helpful as well.

Novice Data Modeling Interview Questions

Q.1 What is DBMS?

Ans.1 DBMS (Database Management System) is a software system that organizes and also manages data in an ordered manner.

 

Q.2 What are the three different types of data models?

Ans.2 The three different types of data models are –

Conceptual Data Model,

Logical Data Model, and

Physical Data Model.

 

Q.3 What is Normalization?

Ans.3 It is the process of designing a database that reduces data redundancy without having to sacrifice integrity. 

 

Q.4 What is Denormalization?

Ans.4 It is a technique where we add redundant data to an already normalized database, thus enhancing the read performance while sacrificing the write performance.

 

Q.5 Why do we consider DBMS a better choice compared to traditional file-based systems?

Ans.5 Only one user can access the data at a time in file systems. However multiple users can access data simultaneously in DBMS. This is one of the important data modeling questions.

 

Q.6 What is Data Abstraction?

Ans.6 Data Abstraction is a process that hides irrelevant details from users.

Advanced-Data Modeling Interview Questions

Q.1 What are the four main types of Database languages?

Ans.1 The four main database languages are-

Data Control Language (DCL),

Data Definition Language (DDL),

Data Manipulation Language (DML) and also

Transaction Control Language (TCL).

This is also one of the important data modeling questions.

 

Q.2 What does the acronym ERD mean?

Ans.2 ERD stands for Entity Relationship Diagram. Also, it is a logical entity representation that defines the relationships between the entities. 

 

Q.3 What is a Surrogate Key?

Ans.3 A Surrogate Key in a DBMS is a unique identifier for either an object in the database or an entity in the modeled world. Unlike a natural or business key, we do not derive the Surrogate Key from application data. We also know it as synthetic key, pseudo key, factless key, entity identifier, or technical key. 

 

Q.4 What is an Enterprise Data Model?

Ans.4 We know the data model which consists of all the entries required by an enterprise as the Enterprise Data Model. 

 

Q.5 What are the common errors you can face in Data Modeling?

Ans.5 The common errors that one can face in Data Modeling are Unnecessary Surrogate Keys, A Missing Purpose as well as Building overly broad data models. 

 

Q.6 What is the definition of a Primary Key?

Ans. 6 A primary key is a column or a set of columns in a regional DBMS table. It thus identifies each record in a unique manner.

Competent Data Modeling Interview Questions

Q.1 What is the goal of Data Modeling?

Ans.1 Data Modeling defines the structure of data. It also explains how the memory stores the data. It also enhances query performance and identifies which tables we should link together. This is one of the important data modeling interview questions.

 

Q.2 What does Data Sparsity mean?

Ans.2 Data Sparsity is the number of blank cells in a database. It is also the amount of data available for a specific dimension. 

 

Q.3 What is a Data Mart?

Ans.3 It is a subset of data warehouses that aligns to a specific line of business or a functional area of an organization. 

 

Q.4 What is Granularity?

Ans.4 It is the level of information that we store in a table. It can be high or low. High-granularity data includes transaction-level data. Low-granularity data has low-level information which we can find in fact tables. 

 

Q.5 What are subtypes and supertypes?

Ans.5 Subtypes are sub-entities that have their own set of properties. Supertypes are entities that have unique qualities that we can find only in high or super-level entities. This is also one of the important data modeling interview questions.

 

Q.6 What are factless fact tables in Data Modeling?

 

Ans.6 It is a table which does not include any facts. Also, they only have dimensional keys and they only include events that occur at the information level not at the computational level.

Proficient Data Modeling Interview Questions

Q.1 Describe the importance of Metadata.

Ans.1 Metadata is the data about data. Also, it explains what types of data are there in the system. Metadata also tells us who is using the data and their reason for using it.

 

Q.2 What is a slowly changing dimension?

Ans.2 The slowly changing dimensions are of four types – 

SCD Type 0,

SCD Type 1,

SCD Type 2, and

SCD Type 3.

They manage both current and historical data in data warehousing. 

 

Q.3 What is the CAP Theorem?

Ans.3 The cap theorem says that no distributed system can ensure Consistency, Availability, and Partition Tolerance all at the same time. A distributed system cannot deliver more than two of the three assurances. 

 

Q.4 What are the different types of dimensions?

Ans.4 There are five types of dimensions. They are –

Role-playing Dimensions,

Confirmed Dimensions,

Slowly Changing Dimensions,

Degenerated Dimensions, and also

Junk Dimensions.

This is one of the important data modeling interview questions. 

Q.5 What is a Confirmed Dimension?

Ans.5 A conformed dimension is a dimension that is attached to at least two fact tables.

 

Q.6 What are Recursive Relationships?

Ans.6 When a relationship exists between an entity and itself it is known as a recursive relationship. 

Expert Data Modeling Interview Questions

Q.1 What is a Junk Dimension?

Ans.1 An abstract dimension table is called a Junk Dimension when there is a grouping of low-cardinality attributes such as flags and indicators which are removed from other tables and junked in these tables. This is yet another one of the important data modeling interview questions.

 

Q.2 Should all databases be made available in the Third Normal Form (3NF)?

Ans.2 It is not strictly necessary. However denormalized databases are easier to maintain and access and are less redundant. 

 

Q.3 What is a derived or artificial primary key?

Ans.3 A derived key is an artificial key that we create, it isn’t already a part of the database. It is different from a natural key. 

 

Q.4 What is the difference between starflake and snowflake schema?

Ans.4 In star schema we just enter the facts and primary keys of the dimensional tables in the fact table. Snowflake is similar but the dimensional tables are in 3NF and are linked by primary, foreign key relations. This is another of the important data modeling interview questions.

 

Q.5 What is forward engineering in Data Modeling?

Ans.5 It is a process during which DDL scripts are generated in Data Models. Databases can be created using these scripts. 

 

Q.6 What is reverse engineering in Data Modeling?

Ans.6 Reverse Engineering is a process used for creating data models from scripts or databases.

 

Those are the important data modeling interview questions.

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Frequently Asked Questions

Q.1 What are the five steps of Data Modeling?

Ans. Maintenance and Optimization, Logical Modeling, Physical Modeling, Conceptual Modeling as well as Requirement Analysis are the five steps of Data Modeling. 

Q.2 What are the four major types of DBMS?

Ans.2 Network database, object-oriented database, hierarchical database, and also relational database are the four types of DBMS.

Q.3 What is the purpose of a data model diagram?

Ans.3 Data Model diagram is used for creating or viewing graphical models of relational database system schemas which includes a range of database objects.

Q.4 What is a data management model?

Ans.4 Data management model is a data structure consisting of well-organized business data for analysis.

Q.5 What are the advantages of DBMS?

Ans.5 There are several advantages of DBMS such as efficient data access and sharing, security and consistency, reduced data inconsistency and redundancy, and improved data integrity.

Recommended Reads

• Top 10 Benefits of Using Data Modeling Tools
• What is a Database? Types, Examples, and Advantages
• What is Big Data Analytics? Why is it important?
• What is RDBMS? Regional Database Management System

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