Teradata Interview Questions and Answers
Most Frequently Asked Teradata Interview Questions
Teradata is a vast parallel open relation data management and processing system primarily used to develop large scale warehousing applications. As this is an open system, it can operate on Linux, Unix and Windows server platform. It also provides support to multiple data warehouse operations at the same time to different clients.
Here are a few benefits of using Teradata for your business:
- Superbly linearly scalable
- Extensive parallel processing
- Shared nothing architecture
- Improved performance of tables>
- Substantially improved compression
Teradata is based on MPP or Massively Parallel Processing architecture. Again, the MPP architecture of Teradata has three core components:
- Parsing Engine (PE) or Optimizer
- Access Module Processor (AMPs)
- Messaging Layer (BYNETs)
|1.||Database Management System primarily used for data analytics.||Widely used Relational database management systems|
|2.||Server operating system: Linux.||Server operating system: AIX, HP-UX, Linux, OS X, Solaris, windows.|
|3.||APIs and another access method: .NET Client API, HTTP REST, JMS Adapter, JDBC, ODBC and OLE DB.||APIs and another access method: ODP.NET, JDBC, ODBC and Oracle Call Interface (OCI)|
|4.||Horizontal partitioning method used.||Sharding partitioning method used.|
Teradata SQL assistance is an advanced web-based query tool which developers used to store, retrieve and manipulate data from Teradata Database or any other database with an ODBC interface Its Java Edition can be used to attach to Teradata Database or any other database that provides the JDBC interface.
|1.||DBMS primarily used for data analytics||A large scale data warehouse service to be used with business intelligence tools.|
|2.||Not based cloud||Cloud-based only|
|3.||Linux server operating system||Hosted server operating system|
|4.||Offers XML support.||No XML support.|
|5.||Offers secondary indexes.||I have restricted secondary indexes.|
|6.||Has triggers||No Triggers|
Teradata IntelliCloud is an as-a-service offering for analytics at scale. It enables businesses to focus on analytic workloads and data warehousing while relying on Teradata for the setup, maintenance, management and support of the infrastructure and software.
Teradata Intelliflex is a platform specially designed for scalable enterprise analytics. It uses an advanced self-service software controls and MPP architecture for scaling of processing data and power capacity independently.
Teradata Tools and Utilities or TTU is a collection of database tools which offer an excellent set of supporting functions to Teradata database.
BTEQ or Basic Teradata Query Script is a file present in Teradata which contains BTEQ commands and SQL statements. The BTEQ script is built for command sequences that are going to be executed on more than one occasion, which can be daily, weekly or monthly.
There have four table types supported in Teradata:
- Permanent Table: It’s the default table and contains data put by the user and stores that data permanently.
- Global Temporary Table: Persistent but the data present in the table will be deleted at the end of the user session.
- Volatile Table: The data into this table is retained only during the user session.
- Derived Table: It holds the intermediate results in a query. The lifetime of this table depends on the query in which they are created, dropped and used.
This is a fundamental question in teradata interview questions.
In Teradata, the primary index is an index present on a set of fields which includes the primary key for the field and is guaranteed not to contain any duplicates.
There are two types of primary indexes:
- UPI / Unique Primary Index
- NUPI /Non-Unique Primary Index
Enlisted new features added to the Teradata:
- New string functions added; PIVOT and UNPIVOT
- Addition of DATASET datatype
- Performance improvement in COUNT DISTINCT
- Introduction of Global Space Accounting
- Unicode Pass-Through added
- Increased PERM and Response Rows (1 MB)
- More choice added to Compression Table-Level Option
In Teradata, fastload is a utility which can be used by developers to load a large amount of data in an empty table on a Teradata system. Its unique features include increased speed to load a huge amount of data in tables.
In Teradata, FastExport is a utility used to export data from Teradata tables into flat files. Teradata – FastExport can also generate the data in report format,
Developers use the UPSERT command inserts rows that do exist. It can be achieved using UPDATE-ELSE-INSERT or MERGE.
Here are the common data types used in Teradata:
Node is a term used for the processing unit (General Purpose) which is controlled by a single operating system. Node is known as the basic building block of Teradata System. The Node is the destination where the processing occurs for the database.
In Teradata, Parsing Engine is a type of virtual processor for session control, SQL parsing and task dispatching in the multitasking and possibly Teradata Database’s parallel-processing environment.
In Teradata, Vproc or Virtual Processor is a simulated processor present in a processing software system, or in a software version of a dedicated physical processor. Each of Vproc uses a portion of the physical processor resource and runs independently of another virtual processor.
In Teradata, Fallback is a feature that offers enhanced data protection beyond that provided by redundant hardware components. Fallback is enabled when a failure occurs, Teradata can continue to perform the update, delete and insert functions because redundant copies of data exist on one or more fallback AMPs.
Teradata utilities offer developers options to quickly load data into a Teradata database or export data from a database of Teradata to a client application.
TPT or Teradata Parallel Transporter is a new generation and advance load/unload utility provided by Teradata. TPT acts as an integrated ETL suite that helps to extract data from multiple sources, load data in target Teradata database and apply transformation logic.
|1.||It removes duplicate records where all columns in the results are the same.||It doesn’t remove duplicate records where all columns in the results are the same.|
|2.||The performance will be impacted with the use of Union as additional work will be performed to remove duplicate rows.||The performance will not be impacted.|