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Questions tagged [olap]

Online Analytical Processing (OLAP) is a category of software tools that provides analysis of data stored in a database, optimized for querying and reporting. OLAP tools enable users to analyze different dimensions of multidimensional data stored for rapid access. For example, it provides time series and trend analysis views.

Online analytical processing (OLAP) is an approach to swiftly answer multi-dimensional analytical (MDA) queries. OLAP is part of the broader category of business intelligence, which also encompasses relational reporting and data mining.

The term OLAP was created as a slight modification of the traditional database term OLTP (Online Transaction Processing). OLAP is a technology that is optimized for querying and reporting, instead of transaction processing. The source data for OLAP is Online Transactional Processing (OLTP) databases that are commonly stored in data warehouses. OLAP data is derived from this historical data, and aggregated into structures that permit sophisticated analysis.

OLAP technologies are used for organizing large business databases and support business intelligence. The OLAP databases are divided into one or more cubes designed the way data is retrieved and analyzed.

Business Intelligence and OLAP

Business Intelligence(BI) helps the business to see the big picture based on the aggregated data, broken down on by any number of variables. Business Intelligence extracts data from OLAP and then analyze it. In this way the business can answer questions like "How do the total sales of all products for 2007 compare with the total sales from 2006?".

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What are OLTP and OLAP. What is the difference between them?

Actually what do they mean? All articles I find about them don't give me an idea, or my knowledge is too insufficient to understand it. Will some one give me some resources with which I can learn this from scratch.
Amarnath R Shenoy
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Data Warehouse vs. OLAP Cube?

Can anyone explain what is really distinction between Data Warehouse and OLAP Cubes? Are they different approach for same thing? Is one of them deprecated in comparison with other? Are there any performance issues in one of them? Any explanation is…
veljasije
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Should OLAP databases be denormalized for read performance?

I always thought that databases should be denormalized for read performance, as it is done for OLAP database design, and not exaggerated much further 3NF for OLTP design. PerformanceDBA in various posts, for ex., in Performance of different…
Gennady Vanin Геннадий Ванин
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Mondrian: Cannot seem to get Aggregation Tables to be used

I have been struggling to get aggregation tables to work. Here is what my fact table looks like: employment_date_id dimension1_id dimension2_id dimension3_id dimension4 dimension5 measure1 measure2 measure3 I'm collapsing the employment_date_id…
chubbsondubs
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Postgresql for OLAP

Does anyone have experience of using PostgreSQL for an OLAP setup, using cubes against the database etc. Having come across a number of idiosyncracies when using MySQL for OLAP, are there reasons in favour of using PostgreSQL instead (assuming that…
davek
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How to learn MDX

I am currently learning OLAP & MDX after many years of relational database development. Any tips on getting started in MDX? What are the best books and resources to learn MDX?
Craig
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Anyone know anything about OLAP Internals?

I know a bit about database internals. I've actually implemented a small, simple relational database engine before, using ISAM structures on disk and BTree indexes and all that sort of thing. It was fun, and very educational. I know that I'm much…
benjismith
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Can OLAP be done in BigTable?

In the past I used to build WebAnalytics using OLAP cubes running on MySQL. Now an OLAP cube the way I used it is simply a large table (ok, it was stored a bit smarter than that) where each row is basically a measurement or and aggregated set of…
Niels Basjes
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Designing dimension hierarchies: Natural or Unnatural

I'm using Analysis Services and when designing dimensions I'm never sure how far to go to build natural hierarchies. What I mean is I've added in all the genuine attribute relationships. So most hierarchies are natural anyway but the most commonly…
Craig
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Benefits of using Staging Database while designing Data Warehouse

I am in process of designing a Data Warehouse Architecture. While exploring various options to Extract data from Production and putting into Data Warehouse, I came across many articles which mainly suggested following two approaches - Production…
Prateek Singh
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What is Multi Dimension OLAP CUBE and give example cube with more than 3 dimensions

As I am new to SSAS, have been reading an article on Multi-Dimension OLAP Cube and struggling to understand Cube concepts, It has been said that Although the term "cube" suggests three dimensions, a cube can have up to 64 dimensions. Could you…
rmdussa
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Build a basic cube with numpy?

I was wondering if numpy could be used to build the most basic cube model where all cross-combinations and their computed value are stored. Let's take the following example of data: AUTHOR BOOK YEAR SALES Shakespeare …
David542
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Connect to Azure analysis services from python

I have Azure analysis service instance, with a tabular model, I need to query the data by DAX or MDX from a python script. I got a connection string from Azure that look's like this: Provider=MSOLAP;Data…
Itzik Friedland
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Why are SQL aggregate functions so much slower than Python and Java (or Poor Man's OLAP)

I need a real DBA's opinion. Postgres 8.3 takes 200 ms to execute this query on my Macbook Pro while Java and Python perform the same calculation in under 20 ms (350,000 rows): SELECT count(id), avg(a), avg(b), avg(c), avg(d) FROM tuples; Is this…
Jacob Rigby
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What options do I have for creating OLAP cubes with Postgres and making it accessible via .net webservices/wcf?

We have a large POSTGRESQL transactional database (around 70 million rows in all), and have previously created a data warehouse from this (updated daily) to run reports off of. To make this more flexible (as lots of different users require different…
Mr Shoubs
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