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The below are the Null value functions in Tearadata. One is "NVL" and another one is "NVL2". These two functions are part of Teradata SQL . NVL -The NVL function replace null value with a string or numeric value. This is the functionality is same as Teradata function NULLIF. It requires two arguments. If the value is not null, it will not do anything. The best SQL Null functions  NVL function:  SELECT NVL (NULL,'USA'), NVL('SPAIN','USA'); ----------- USA SPAIN Also Read: Top 70 Teradata Interview Questions The NVL2 function : Returns one of two specified values (arguments#2 and Arguments#3) based on weather the first arguments in NULL or not. It requires three arguments. The rule is as follows: If expression 1 is not null, expression 2 is returned If expression 1 is null, expression 3 is returned The best NVL2 example SELECT NVL2(NULL,'FRANCE','SPAIN'), NVL2('ENGLAND','FRANCE','SPAIN'

The pseudo table mechanism is a way to serially queue all table level locks through the use of an internal pseudo table. In this table the database locks the row hash of the table's table ID.

Every table must have at least one column as the Primary Index. The Primary Index is defined when the table is created.There are two reasons you might pick a different Primary Index then your Primary Key. They are (1) for Performance reasons and (2) known access paths. Primary Index Rules  Rule 1: One Primary Index per table. Rule 2: A Primary Index value can be unique or non-unique. Rule 3: The Primary Index value can be NULL. Rule 4: The Primary Index value can be modified. Rule 5: The Primary Index of a populated table cannot be modified. Rule 6: A Primary Index has a limit of 64 columns. Two Types of Primary Indexes (UPI or NUPI)  Unique Primary Index(UPI) - A Unique Primary Index (UPI) is unique and cannot have any duplicates. If you try and insert a row with a Primary Index value that is already in the table, the row will be rejected. An UPI enforces UNIQUENESS for a column Non-Unique Primary Index (NUPI) - A Non-Unique Primary Index (NUPI) means that the values for

Teradata Architectural Questions  QUESTION No:1 An administrator is trying to manage resources on the system because there is a business critical reporting requirement. The reporting workload starts at 9AM and is required to finish by 10AM. At the same time, ad hoc users are allowed to access the system. The administrator is building a Query Resource Throttle in TDWM to better manage the resources. Which two are available as options for building the throttle? (Choose two.) A. Index Scan Types Allowed B. Throttle All-AMP Queries Only C. No Aggregate Functions Allowed D. Only limit queries with Step Time Threshold Answer: C,D QUESTION NO: 2 An administrator is asked to keep a daily backup of a very large transaction table. The table is defined with a PPI with a daily partitioning expression on insert date and the table is insert only. There is not enough of a window to backup the entire table each night. In this situation, which backup strategy is the best approach? A. Implement a