Teradata and fall back
tom
I understand Teradata has a so-called fall back option. The idea is that data are stored twice; each record being stored to two different amps. I saw a nice picture…
Dynamic SQL
I must confess I never heard of Dynamic SQL. But suddenly around me everyone started talking on Dynamic SQL. What is dynamic SQL? Dynamic SQL is a SQL statement that…
MOLAP and ROLAP
I currently work in an organisation that has a debate on whether to use MOLAP or ROLAP. But first of all: what is discussed here? ROLAP and MOLAP are two…
Duplicate records in teradata tables
Teradata offers the user the choice whether of not a check is made on duplicate records. Let’s first look at some code that allows duplicate records to be inserted. The…
The Teradata answer on materialised views
Teradata has a feature that is designed to increase the performance of queries. This feature is called the “join index”. Such a join index is a structure that stores the…
Soft RI in Teradata
Teradata has the concept of “Soft RI”. In this concept, a foreign key is created but its restriction is not enforced. What happens in that situation? Let’s look at the…
Different codepages in SQL Server
It is possible in SQL Server to create columns in a table that have different codepage. This can be shown in the table below. That table has two attributes: char_unicode…
Codepages
Recently, I encountered the issue of codepages again. The problem was that the name of a Turkish city (İstanbul) was not represented correctly. Again a codepage issue. The character İ…
Running scripts in teradata
Let us assume, we have a data warehouse in teradata. Let us suppose that this data warehouse is loaded with a set of scripts. In principle it could be done.…
PIN code
A few days ago, I got the suggestion to protect a transaction with a PIN number. But how does that mechanism work? It looks as if this mechanism is used…