Types of measure

Type of measure
1.Additive measure: - Can be summed across all dimensions such as sales amount.
2.Semi-additive measure: - can be aggregated across all dimensions except Time such as Account and inventory balance. If we attempt to aggregate these measures across time then we will get the wrong value. Exp. Bank account has balance 400 in Jan and 600 in Feb.
3.Non-Additive measure: - can’t be meaningfully aggregated across any dimension, such as Rates and percentages. We can use MDX Expression to define how they aggregated.

Data Modeling Techniques

Data Modeling Techniques
Data modeling is a method used to define and analyze data requirements needed to support the business processes of an organization. The data requirements are recorded as a conceptual data model with associated data definitions. Actual implementation of the conceptual model is called a logical data model. To implement one conceptual data model may require multiple logical data models. Data modeling defines not just data elements, but their structures and relationships between them Data modeling techniques and methodologies are used to model data in a standard, consistent, predictable manner in order to manage it as a resource.

 

 

 

Three basic styles of data model:

 

 

• Conceptual data models: These models, sometimes called domain models, are typically used to explore domain concepts with project stakeholders. high-level conceptual models are often created as part of your initial requirements envisioning efforts as they are used to explore the high-level static business structures and concepts

• Logical data models (LDMs) :- LDMs are used to explore the domain concepts, and their relationships, of your problem domain. This could be done for the scope of a single project or for your entire enterprise. LDMs depict the logical entity types, typically referred to simply as entity types, the data attributes describing those entities, and the relationships between the entities.

• Physical data models (PDMs):- PDMs are used to design the internal schema of a database, depicting the data tables, the data columns of those tables, and the relationships between the tables.

Modeling methodologies

 

• Bottom-up models 
• Top-Down models 

Data Modeling Techniques for Datawarehouse

Two data modeling techniques that are relevant in a data warehousing

environment are ER modeling and dimensional modeling.
ER modeling produces a data model of the specific area of interest, using two
basic concepts: entities and the relationships between those entities. Detailed
ER models also contain attributes, which can be properties of either the entities
or the relationships. The ER model is an abstraction tool because it can be used
to understand and simplify the ambiguous data relationships in the business
world and complex systems environments.

Dimensional modeling uses three basic concepts: measures, facts, and
dimensions. Dimensional modeling is powerful in representing the requirements
of the business user in the context of database tables.
Both ER and dimensional modeling can be used to create an abstract model of a
specific subject. However, each has its own limited set of modeling concepts
and associated notation conventions. Consequently, the techniques look
different, and they are indeed different in terms of semantic representation

Dimension modeling VS ER modeling

Difference between Dimension modeling and E-R modeling(Relational modeling)

•The E-R diagram is split as per the entities like Customer,Product etc and its attributes would be textual and numeric(fact or calculation) . A dimension model is split as per the dimensions and facts. dimension only contains textual attributes and numeric values will comes under fact table.

. The E-R modeling will be more normalized (used as a OLTP) with optimum index but in Dimension moduling would be less normalized (used as a OLAP) with maximus number of index to boost the search performance.

. Dimension modeling will help you to desing database for desicion support system but E-R modeling is used for Transaction processing database.

.An E-R diagram is a complex maze of hundreds of entities linked with each other (more relationship between entities), whereas the Dimensional model has logical grouped set of star-schemas or snowflacs.

. Performance of Insert,Delete and update operation would be high and search would be comparatively slow in ER modeling but Dimension modeling Search would be faster and lest operation would be slower.

Fande ka Fanda

To steal ideas from one person is plagiarism; to steal from many is research.

Man's commonest fault is not knowing what he doesn't know.

If you can't be a good example, then you'll just have to serve as a horrible warning.

One of the life's mysteries is how a two pound box of candy can make a person gain five pounds.

Beware of false knowledge; it is more dangerous than ignorance.


Why in a country of free speech, why are there 'phone bills?

If the cops arrest a mute, do they tell him he has the right to remain silent?

The only thing constant in life, is change.

Life is not measured by the number of breaths we take, but by the moments that take our breath away.

Who tastes dog food when it has a 'new & improved' flavour?

Do you realize that the only time in our lives when we like to get old is when we're kids? If you're less than 10 years old, you're so excited about aging that you think in fractions.
'How old are you?' I'm four and a half!' you're never thirty-six and a half. You're four and a half, going on five! That's the key.
Life is not measured by the number of breaths we take, but by the moments that take our breath

Find nth highest salary

Find 1, 2,3 and nth highest salary

select top 1 salary from (
select distinct top n salary from tab order by salary desc ) a
order by salary asc

Difference between HTTP Post and HTTP Get method.

Both HTTP GET and HTTP POST use HTTP as their underlying protocol. Both of these methods encode request parameters as name/value pairs in the HTTP request.

HTTP GET :-
1. All the name value pairs are submitted as a query string in URL. it means The GET method creates a query string and appends it to the script's URL on the server that handles the request.
2. It's not secured as it is visible in plain text format in the Location bar of the web browser.
3. Length of the URL string is restricted upto 255 character
4. this is the default method used. if you not mention in Form Tag.
5. If get method is used and if the page is refreshed it would not prompt before the request is submitted again.
6. Data is always submitted in the form of text

HTTP POST :-
1. The POST method creates a name/value pairs that are passed in the body of the HTTP request message means All the name value pairs are submitted in the Message Body of the request.
2. Post Method is secured because Name-Value pairs cannot be seen in location bar of the web browser.
3. Length of the string (amount of data submitted) is not restricted.
4. If post method is used and if the page is refreshed it would prompt before the request is resubmitted.
5. use request object to get the value of posted control.


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Goals

वजन बात में होनी चाहिए, आवाज में नहीं !!!

The tragedy of life doesn't lie in not reaching your goal. The tragedy lies in having no goals to reach.

Do it now. You become successful the moment you start moving toward a worthwhile goal.

One part at a time, one day at a time, we can accomplish any goal we set for ourselves."
a person who has a long-term goal that will take a few years to achieve. The individual seemed overwhelmed with the size of the goal and was getting discouraged. Their focus was on all the things they need to do to reach the goal and their comment to me was, "I just can't do it". It reminded me of the story of the clock that had been running and running:

This clock had sat on the mantle for years. And it ran and ran.

One day, the clock began to think about how many times it had to tick during the year. It counted up the seconds - it would have to tick 31,536,000 times a year.

The clock seemed overwhelmed - "I can't do it, that is just too much." So the clock stopped ticking.

Then somebody reminded the clock that it didn't have to tick the 31,536,000 seconds all at one time, but rather one tick at a time.

The clock then realized this was okay and started ticking again!

When we set our goals, it is good to visualize the end results. But, getting to our goal is doing a little bit every day; not doing it all at once. So the next time you find yourself overwhelmed by your goal, remember the clock and the number of ticks - do a little bit every day and over time you will reach your goal. Believe me, reaching your goal is worth it!