Compared to their predecessors they change the demands on database design. One of the most central of these demands is the idea of evolutionary architecture. On an agile project you assume that you cannot fix the requirements of the system up-front. As a result having a detailed design phase at the beginning of a project becomes impractical.
Download script - 8. Why and when does an organization or company need to plan to go for data warehouse designing? We will take a quick look at the various concepts and then by taking one small scenario, we will design our First data warehouse and populate it with test data.
If you are thinking what is data warehouse, let me explain in brief, data warehouse is integrated, non volatile, subject oriented and time variant storage of data. Whenever your data is distributed across various databases, application or at various places stored in different formats and you want to convert this data into useful information by integrating and creating unique storage at a single location for these distributed data at that time, you need to start thinking to use data warehouse.
In another case, if your daily transactional data entry is very huge in your database, maybe millions or billions of records, then you need to archive these data to another Archive database which holds your historical data to remove load from live database and if you are creating your two dimensional report on this archive database then your report generation is very slow on that data it may take couple of minutes to couple of hours or it can give you timeout error.
On this two dimensional data, even you cannot do any type of trend analysis on your data, you cannot divide your data into various time buckets of the day or cannot do study of data between various combination of year, quarter, month, week, day, weekday-weekend.
In this scenario to take perfect decision on the basis of your historical data, you have to think to go for designing of data warehouse as per your requirement, so you can study data using multiple dimensions and can do better analysis to take accurate decision.
Designing of data warehouse helps to convert data into useful information, it provides multiple dimensions to study your data, so higher management can take Quick and accurate decision on the basis of statistics calculated using this data, this data can also be utilized for data mining, forecasting, predictive analysis, quicker reports, and Informative Dash board creation, which also helps management in day to day life to resolve various complex queries as per their requirement.
But how do you make the dream a reality? First, you have to plan your data warehouse system. So modeling of data warehouse is the first step in this direction. Scenario X-Mart is having different malls in our city, where daily sales take place for various products.
So they asked us to design a system which can help them quickly in decision making and provide Return on Investment ROI.
Let us start designing of data warehouse, we need to follow a few steps before we start our data warehouse design. Developing a Data Warehouse The phases of a data warehouse project listed below are similar to those of most database projects, starting with identifying requirements and ending with executing the T-SQL Script to create data warehouse: Identify and collect requirements Execute T-SQL queries to create and populate your dimension and fact tables Identify and Collect Requirements We need to interview the key decision makers to know, what factors define the success in the business?
How does management want to analyze their data? What are the most important business questions, which need to be satisfied by this new system?
We also need to work with persons in different departments to know the data and their common relations if any, document their entire requirement which need to be satisfied by this system.
Let us first identify the requirement from management about their requirements. Need to see daily, weekly, monthly, quarterly profit of each store. Comparison of sales and profit on various time periods. Comparison of sales in various time bands of the day.
Need to know which product has more demand on which location? Need to study trend of sales by time period of the day over the week, month, and year?
On what day sales is higher? On every Sunday of this month, what is sales and what is profit? What is trend of sales on weekday and weekend? Need to compare weekly, monthly and yearly sales to know growth and KPI?
Design the Dimensional Model We need to design Dimensional Model to suit requirements of users which must address business needs and contains information which can be easily accessible. Design of model should be easily extensible according to future needs.
This model design must supports OLAP cubes to provide "instantaneous" query results for analysts. Dimension The dimension is a master table composed of individual, non-overlapping data elements. The primary functions of dimensions are to provide filtering, grouping and labeling on your data.
Dimension tables contain textual descriptions about the subjects of the business. Let me give you a glimpse on different types of dimensions available like confirmed dimension, Role Playing dimension, Degenerated dimension, Junk Dimension. Slowly changing dimension SCD specifies the way using which you are storing values of your dimension which is changing over a time and preserver the history.
Let us identify dimensions related to the above case study. Product, Customer, Store, Date, Time, Sales person Measure A measure represents a column that contains quantifiable data, usually numeric, that can be aggregated.
A measure is generally mapped to a column in a fact table. For your information, various types of measures are there.
Additive, semi additive and Non additive. Let us define what will be the Measures in our case.I think this is the Easiest way to populate a table with ResultSet with a method like.
FillTable(MyTable, "select * Customers;"); And a very simple method can be made as. In this article, I am going to show you the importance of data warehouse? Why and when does an organization or company need to plan to go for data warehouse designing? We will take a quick look at the various concepts and then by taking one small scenario, we will design .
I am trying to accomplish the following: Take a snapshot of the original database, create and exact a duplicate on another server?
Take a snapshot of the original database, create a duplicate on the. In this staff database project we will be developing an Excel application that will use the coding method from our previous tutorial "Create and Awesome Database in Seconds". I will show you here how to use this code can take it to a completed application with all its bells and whistles.
Create and populate a test database to run Cucumber tests on. Ask Question. I understand that the typical way to create data for the test database would be to write Gherkin tables and put them in the background block of a cucumber file.
But I already have a Ruby script that creates samle data suitable for the test database. site design.
Introduction What is a database? The Hierarchical Data Model The Network Data Model The Relational Data Model - The Relation - Keys - Relationships - Referential Integrity.