Teradata is an enterprise software company. It develops and sells database analytics software. Business analytics, cloud products, and consultancy are the three primary services offered by the organization. It is active throughout North and Latin America, Europe, the Middle East, Africa, and Asia.
The company's main office is in San Diego, California. Teradata also has significant U.S. locations in Atlanta and San Francisco, where its data center research and development is carried out.
This article will be focused on the most commonly asked Teradata interview questions that will help you prepare for interviews with big MNCs.
Let's continue with some of the top Teradata interview questions.
Easy Teradata Interview Questions
1. What is the Teradata tool?
Teradata is an RDBMS or Relational DataBase Management System. It is an open-source system. It is able to run on different operating systems, like Windows, Linux, and macOS. Teradata helps big organizations manage large data warehouse operations to improve their performance. The key feature of this tool is Parallelism or parallel execution. Using the parallel execution concept, you can execute multiple data warehouse operations simultaneously. You can also break a single task into smaller parts and process them parallelly using Parallelism.
2. What is the importance of using Teradata?
Following are the reasons for using Teradata:
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The system can handle, i.e., storing and processing a large amount of data, even more than 50 petabytes.
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You can integrate Teradata with various business intelligence (BI) tools.
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Teradata supports OLAP or Online Analytical Processing, allowing users to perform complex analytics on their data.
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Teradata also offers a comprehensive set of services concerning data warehousing, like cloud-based and hardware-based data warehousing, business analytics, etc.
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Teradata supports SQL or Structured Query Language as a means of interacting with data that is stored in the tables.
3. What are Teradata's newest features?
Following are some of the newest features of Teradata:
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Unlimited Parallelism,
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Linear Scalability,
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Shared Nothing Architecture,
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Connectivity,
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Structured Query Language,
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Mature Optimizer,
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Low TCO (Total Cost of Ownership).
4. What are Teradata utilities? Can you name some utilities?
Teradata utilities are tools that can be used to load as well as export data to and from the Teradata database. Some of the utilities are:
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Basic Teradata Query,
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Fastload,
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Multi-load,
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Fastexport, and
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Teradata Parallel Data Pump or TPump.
5. Can you explain different string manipulation functions and operators in Teradata?
We can use String functions to manipulate strings in Teradata. It supports some of the standard string functions. It also supports Teradata extensions to standard functions.
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SUBSTRING: It extracts a portion from a long string based on the choice. For example,
SELECT SUBSTRING('CodingNinjas' FROM 1 FOR 4);
Output:
Codi
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POSITION: It is used to locate a character in a String (ANSI Standard). For example,
SELECT POSITION("o" IN "CodingNinjas");
Output:
2
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TRIM: It removes all the blank space from a string. For example,
SELECT TRIM(" CodingNinjas ");
Output:
CodingNinjas
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UPPER: It converts the string into uppercase. For example,
SELECT UPPER("CodingNinjas");
Output:
CODINGNINJAS
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LOWER: It converts the string into lowercase. For example,
SELECT LOWER("CODINGNINJAS")
Output:
codingninjas
6. Why doesn't Multi-load support a Unique Secondary Index (USI) instead of a Non-Unique Secondary Index)?
All AMP (Access Module Processors) can function independently, thanks to Teradata. With USI, the index subtable would need to be present on several AMPs, requiring AMP-to-AMP communication. However, NUSI would place the index subtable on the same AMP as the data row, allowing that AMP to be handled separately. For this reason, multi-load supports NUSI.
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7. How do you restart MLOAD Client System when it fails?
Whether a Teradata MultiLoad job halted during the application phase (applying all DML (Data manipulation language ) procedures) or was terminated due to a client system failure, the job can be restarted.
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If the Teradata MultiLoad job was interrupted before or after the application phase, you could restart the job precisely as it was without making any modifications to the script. Teradata MultiLoad establishes its stopping point using the entries from the restart log database and starts processing there.
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If a Teradata MultiLoad job is stopped or the client system fails during the application stage, you must resolve the issue that led to the failure and then restart the job.
8. How do you restart MLOAD Teradata Server after its execution?
Typically, the process starts from the most recent checkpoint and after executing the MLOAD script. Then the server is restarted.
9. What do you mean by performance tuning?
To be more precise, Teradata Performance tuning includes locating and eliminating all database bottlenecks. Although the bottleneck delays data retrieval from the database, it does not cause mistakes. Without database performance tuning, a business can see inconsistent query results, making accessing its data more difficult and leading to additional problems.
10. What do you mean by Skewness in Teradata? What is its usage?'
In Teradata, "Skewness" is the row distribution on AMPs (Access Module Processors). In data distribution, the Skew Factor is the distribution of table data among AMPs. A skewed factor of 0 denotes an equal data distribution among the AMPs. When data is highly skewed, it indicates that the distribution is not uniform and that some AMPs contain more rows while others have relatively few. This case's high Skew Factor (unequal data distribution) impacts Teradata's Parallelism and performance.
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