May
16
by admin
Before you start with SI, well I must say that as a prerequisite you must first read about the Primary index in Teradata. So after knowing about Primary index the point here is that when we already have UPI and NUPI then what’s the use of this Secondary Index? Well the best possible answer for …
May
11
by admin
When you want to retrieve the rows from the table, the very first step in explain plan is the pseudo table lock on that table e.g – Type select * from <databasename>.<tablename> in the SQL assistant, and do the explain plan for this table. The very first step you see is – 1) First, we lock …
Apr
21
by admin
We know that in Teradata all the tables are either SET or MULTISET. The difference between SET and MULTISET tables is – SET tables – SET tables did not allow duplicate values in the table. e.g. COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 A b c d H g y k A …
Mar
14
by admin
Teradata database has become so popular today that you will often find many Teradata certification courses and online Teradata certification training resources. To become an Teradata Certified Professional, you will need to learn all the Teradata certification test objectives. Most of us are concern about the practice or sample questions for various Teradata exams. These …
Feb
24
by admin
Teradata is consistent with hashing a value. It means that when Teradata hashes the Index value (e.g. ‘teradatatech’) it will come up with a Row Hash. Now if Teradata hashes the same index value (‘teradatatech’) million times it will always come up with the same Row Hash. Teradata always hashes the same value with consistent …
Feb
21
by admin
Statistics are data demographics (or hints) used by the Teradata optimizer. There are many ways to generate a query plan for a given SQL, and collecting statistics ensures that the optimizer will have the most accurate information to create the best access and join plans. The optimizing phase of Teradata, makes decisions on how to …
Dec
25
by admin
The join index JOIN the two tables together and keeps the result set in the permanent space of Teradata. This JOIN index will hold the result set of the two table, and at the time of JOIN parsing engine will decide whether it is fast to build the result set from the actual BASE tables …
