Top 20 SQL Interview Questions with Answers

SQL is a language for accessing and manipulating database standardized by ANSI. To be successful with database-centric applications (which includes most of the applications Data Warehousing domain), one must be strong enough in SQL. In this article, we will learn more about SQL by breaking the subject in the form of several question-answer sessions commonly asked in Interviews.

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Performance Considerations for Dimensional Modeling

Performance of a data warehouse is as important as the correctness of data in the data warehouse because unacceptable performance may render the data warehouse as useless. There is this increasing awareness about the fact that it’s much effective to build the performance from the beginning rather than to tune the performance at the end. In this article we have a few points that you may consider for optimally building the data model of a data warehouse. We will only consider performance considerations for dimensional modeling.
Published 3 months ago under Dimensional Model

Comparing Performance of SORT operation (Order By) in Informatica and Oracle

In this "DWBI Concepts' Original article", we put Oracle database and Informatica PowerCentre to lock horns to prove which one of them handles data SORTing operation faster. This article gives a crucial insight to application developer in order to take informed decision regarding performance tuning.
Published 3 months ago under Informatica

Informatica Performance Tuning - Complete Guide

This article is a comprehensive guide to the techniques and methodologies available for tuning the performance of Informatica PowerCentre ETL tool. It's a one stop performance tuning manual for Informatica.
Published 3 months ago under Informatica

How to Tune Performance of Informatica Lookup Transformation

To me, look-up is the single most important (and difficult) transformation that we need to consider while tuning performance of Informatica jobs. The choice and use of correct type of Look-Up can dramatically vary the session performance in Informatica. So let’s delve deeper into this.
Published 3 months ago under Informatica

How to Tune Performance of Informatica Joiner Transformation

Joiner transformation allows you to join two heterogeneous sources in the Informatica mapping. You can use this transformation to perform INNER and OUTER joins between two input streams. For performance reasons, I recommend you ONLY use JOINER transformation if any of the following condition is true –
Published 3 months ago under Informatica

How to Tune Performance of Informatica Aggregator Transformation

Similar to what we discussed regarding the Performance Tuning of Joiner Transformation, the basic rule for tuning aggregator is to avoid aggregator transformation altogether unless...
Published 3 months ago under Informatica

Dimensional Modeling Approach for Various Slowly Changing Dimensions

In our earlier article we have discussed the need of storing historical information in dimensional tables. We have also learnt about various types of changing dimensions. In this article we will pick "slowly changing dimension" only and learn in detail about various types of slowly changing dimensions and how to design them.
Published 3 months ago under Dimensional Model

The 101 Guide to Dimensional Data Modeling

In this multi part tutorial we will learn the basics of dimensional modeling and we will see how to use this modeling technique in real life scenario. At the end of this tutorial you will become a confident dimensional data modeler.
Published 3 months ago under Dimensional Model

Common Mistakes in Data Modelling

A model is an abstraction of some aspect of a problem. A data model is a model that describes how data is represented and accessed, usually for a database. The construction of a data model is one of the most difficult tasks of software engineering and is often pivotal to the success or failure of a project.
Published 3 months ago under Dimensional Model