SEEQUALITY.NET -> NEW SITE

Hello,

I am proud to announce that i have created new site called SEEQUALITY.NET. All content has been moved there, new articles, videos and curses about SQL Server, Business Intelligence, Data Science and .NET will appear there every day!

So please visit my new website, subscribe and learn.

Thanks!

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Kilka słów o: konkatenacja pól z wartością NULL

Próbowaliście kiedyś łączyć wartości kilka pól i w wyniku tej operacji otrzymywaliście NULL? Dzieje się tak ze względu na fakt, iż NULL jest nieporównywalny z żadnym typem danych tak więc dodanie jakiejkolwiek wartości do NULL w rezultacie daje NULL. Aby obejść ten problem mamy kilka możliwości, które postaram się przedstawić w dalszej części tego artykułu.

W SQL Server możemy znaleźć właściwość CONCAT_NULL_YIELDS_NULL. Kontroluje ona zachowanie SQL Server w przypadku konkatenacji pól zawierających wartość NULL. Domyślnie jest ona włączona. Dla przykładu

SET CONCAT_NULL_YIELDS_NULL ON

GO

SELECT ‘abc’ + NULL AS RESULT

SET CONCAT_NULL_YIELDS_NULL OFF

GO

SELECT ‘abc’ + NULL AS RESULT

concat_nulls

 

 

 

 

 

 

Jak widać w bardzo prosty sposób można zmodyfikować zachowanie SQL Server jeśli chodzi o wartości NULL. Jednak nie zaleca się modyfikacji tej opcji, pożądany efekt można osiągnąć w lepszy sposób. A mianowicie używając funkcji ISNULL lub też COALESCE.

SELECT ISNULL(‘abc’,”) + ISNULL(NULL,”) AS RESULT

SELECT COALESCE(‘abc’,”) + COALESCE(NULL,”) AS RESULT

 

concat_nulls2

 

 

 

 

 

 

Jedyna różnica pomiędzy tymi funkcjami jest taka, że ISNULL może zamiast pola podstawić tylko jedną wartość a COALESCE wiele. Myślę, że znajomość tych trzech bardzo prostych funkcjonalności pozwala na rozwiązanie bardzo wielu problemów na które napotykamy w codziennej pracy.

Few words about: MDXMissingMemberMode

Today I would like to write few words about MDXMissingMemberMode. This is property of a dimension in SSAS and sometimes a need occur to change its default value.

MDXMissingMemberMode has three possible values:

  • Default
  • Error
  • Ignore

where Default is Ignore. When we leave default value, all references in our MDX code that point to non existing members of dimension hierarchy will be ignored and client tool like SSMS will return empty result, for example

select {} on 0,

[Customer].[Customer].&[186951] on 1

from [Adventure Works]

Return nothing because member with uniqe name [Customer].[Customer].&[186951] doesn’t exist. When we set MDXMissingMemberMode to Error then we will get:

Query (2, 1) The level ‘&[186951]’ object was not found in the cube when the string, [Customer].[Customer].&[186951], was parsed.

Default behavior of this property is needed in most cases when we deal with flexible hierarchies – because when member moves from one parent member to another it automatically changes his unique name – but sometimes it will be useful to change this default behavior.

Few words about: Unary operators in SSAS

Today’s topic will be the unary operators in Analysis Services. They allow us to build custom rollup operations in hierarchies. In standard hierarchies, eg. Parent-Child child elements are aggregated to parent with one standard operator defined, in most cases it will be + operator. But sometimes we need to create something custom and then unary operators come up.

Unary operators allow us to build some interesting feature based on dimension table like this:

parent-child-table

This table shows that:

Total=LevelA+LevelB

LevelA=LevelA1-LevelA2-LevelA3

LevelB=-LevelB1

Continue reading

Few words about: SQLDAY 2014!

 

Image

 

I am pleased to announce that I will be attendee in annual SQL Server conference called SQLDay. Here you have description of the event from their website(http://conference.plssug.org.pl/) :

SQL Day 2014 is a special event organized by the Polish SQL Server Users Group (PLSSUG) to celebrate the birth of the group. This time it’s the seventh birthday. Again, welcome to the capital of Lower Silesia, Wroclaw, a city of many cultures, innovations and meetings. Wroclaw is one of the oldest and most beautiful cities in Poland. Located at the foot of the Sudeten on the Oder River through by its numerous tributaries and canals, is a unique city of 12 islands and more than a hundred bridges. It is the greenest city in Polish – the one inhabitant of 25 m2 of green (not counting the green housing estate). Wroclaw is constantly changing, building, expanding and modernizing. This year’s event will be held at New City Stadium – the same place where the matches of EURO 2012.

This year’s conference formula is similar to the previous one: the conference will last three days, during which participants will be able to participate in several workshops (Pre-Conf), led by speakers of Polish and invited guests from abroad and dozens of technical sessions.

Venue:
The conference will take place in the Municipal Stadium in Wroclaw LINK
Date of the conference:
April 28 (workshops) and April 29-30 (conference sessions)

 

Hello world!

Hello,

I would like to invite you to my blog where you can find some useful(or not) information about technology, especially Microsoft technology like Business Intelligence and database solutions (SQL Server). From time to time i will post something about .NET and the other  that i have to work with or which are interesting for me.

Finally i would like to invite you to take part in this blog, ask some questions and maybe write something interesting that i can post 🙂 visit achodkowski.wordpress.com from time to time – i want to blog on weekly basis.

If you want to find english posts please select “English” tag or Click here.

Jeśli chcesz znaleźć posty po polsku wybierz tag “Polish” albo Kliknij tutaj.

Thanks!

Adrian