Teradata 面试题与答案

问题 11. Explain the purpose of the Teradata PRIMARY KEY constraint.

The PRIMARY KEY constraint in Teradata is used to uniquely identify each row in a table. It ensures that the values in the specified columns are unique and not NULL.

Example:

问题 12. What is a Teradata Join Index, and when would you use it?

A Join Index in Teradata is a type of database object that is created to improve the performance of specific join queries. It precomputes and stores the result of a join operation to speed up query processing.

问题 13. How does Teradata handle skewed tables, and what strategies can be used to address skewness?

Teradata uses various techniques such as hash redistributions and skewed join strategies to handle skewed tables. Skewness can be addressed by proper indexing, collecting statistics, and using appropriate join strategies.

问题 14. Explain the use of the Teradata Aggregate Functions.

Teradata provides various aggregate functions like SUM, AVG, MIN, MAX, and COUNT to perform calculations on a set of values. These functions are commonly used in SELECT queries for summarizing data.

Example:

问题 15. What is Teradata's FastLoad utility, and when would you use it?

FastLoad is a Teradata utility used for fast loading of large volumes of data into an empty table. It bypasses the normal SQL processing and loads data directly into the target table, making it highly efficient for initial data loads.