Benefits of Data Warehouse (Part 4)

The advantage and benefits of data warehouse over other forms of information reporting system is in:

• Merging diverse data from multiple sources (multiple production systems) implemented on different platforms.
• Rapid detection of the changes in the source system.
• Iterative character of the model building data warehouses and hence the iterative nature of building software for extraction.
• Detection of errors in a production system
• Lasting data storage (typically 5-10 years) in relation to production systems (typically 1-2 years)

Data gathering

Data gathering is an important feature of the data warehouse. The information system of companies in many cases, is comprised of multiple subsystems, physically separated and built on different platforms. Such non-integrated information system is a major problem for a system of reporting within the company. The problems of timely collection of all necessary data, inconsistencies among the reports obtained from various sources covering the same area of business within the company, are reporting poor. Data Warehouse performs integration of all existing data sources and makes them accessible in one place. That process of collecting and integrating data from all available sources, the most difficult task in building a data warehouse.

More  information in Data Warehousing PDF.

Each component of the production information system is a potential source of data for data warehouse. Only the data warehouse does not allow a direct, manual entry of data into it. Manual entry of individual records in a data warehouse is not permitted nor necessary because the data already entered the production information system company (this is a basic purpose of the production system). On the other hand, input data into data warehouse is done automatically, periodically and in large quantities. For example, it may be decided that the end of each working day to perform data collection and aggregation of data from any available source, production systems and to transfer them in a data warehouse. This job will perform software system that must be built and run in fixed time intervals. The time interval between transmission of data (data warehouse refresh period) may be one day, week or month for example, depending on how up to date data is needed. In the time between two refreshes, the base data warehouse is quiet, ie the base is not for any input data but only read from the database of data warehouse. Of course, here we face the fact that the warehouse data always have old data from yesterday or last week or month. This may seem like a disadvantage, however, the purpose of data warehousing is such that it does not require the condition as it was in this moment. Data Warehouse uses the administrative structure of the company that sets the types of questions: “How much I earned in the last month when it comes to foreign business partners of the realization of what is charged in the same period last year,” or “What is the most problematic categories of users in terms of returning the loan and how much the average delay in the case of married, male with more than two children? “. Daily data warehouse refresh period is quite sufficient for your first question when the monthly period more than good for the other issue that takes into account the historical data that can sezati up to ten years. One day delay can make a significant difference. Further, as between two refresh does not perform any input into the database storage of data, statements made during this time certainly would be consistent, which may not be the case with statements from the production system in which the data fluctuate due to the continuous input. Of course, if we ask the question: “What is the state party’s bank account?” then we will use the data warehouse for production information system that shows the way this is just a minute or seconds.

Prerequisites for building the system for data transmission

The detailed elaboration of the process data can be set off only after the following conditions are met:

1st Defined as (initial) requirements of users in terms of necessary data.
2nd Are available to people well enough to know the structure and content of the source system.
3rd The source system is not capable of the construction or modification of a logical structure.

The first requirement means that there is at least a sketch data model, ie a list of measures and dimensions that the user wants the data warehouse database. Without fulfilling this requirement is, obviously, can not go into the design phase retrieval.

The second requirement is extremely important. Because of the complexity of the sources, it is very difficult to find contact information, to determine the exact algorithm to obtain information without a good connoisseur of the source system. The importance of this requirement has proved to be of practical project to build a data warehouse of the Zagreb Fair, when the source familiar with the system were not always available team to build warehouses. Because it is often ignored some important facts related to the complex structure and content of source data, a result was inaccurate retrieval algorithm. This situation is repeated several times in a project to build a warehouse, resulting in constantly changing, but mostly written in code, and thus necessarily delay the project.

The reasons for setting up the third terms are obvious. If the structure of the source system is not stable, the algorithm retrieval may be subject to frequent change. Time limits can be incorporated, which leads to customer dissatisfaction, etc.
 

Data warehouse in work

 Working with data warehouse can be viewed as two separate parts. One is the automated process of daily data and the other interactive work users with applications where the data source data warehouse.
Daily data recovery

Data Warehouse has a certain amount of time in which the data is refreshed. Typically, the data warehouse is updated once a day, in order to relieve hardwareski resources to be carried out mostly at night and not disturbing the normal operation. Refreshing the data is completely automated and requires no action by the people. In case of any mistakes in the production system was in the process of refreshing the relevant people (developers and builders warehouse administrators), it is automatically noticed.

Working with tools for viewing data warehouse

 Tools for interactive viewing of data warehouses (which has already been done, therefore they should be differentiated from the program for building a data warehouse) can be already finished products such as Oracle Discoverer or user applications such as dairy dates in Oracle Application Express. These programs are adapted to work with data warehouses and are intended as decision support for administration, etc. They differ from Oracle Discoverer, which are generally adapted to the company for koej statements were made and what they need. The results of these programs get basically all the summary level and do not deal with individual records (for example, are typical of such reports by region rather than statements by customers “from first to last, such reports as the user must wait for the (quality) production system and not from the data warehouse). Very generalized, saying the production system should have the better answer to the analytical data warehouse to the question of synthetic character.

Interaction with Office package (Word, Excel)

Because the distribution of MSOffice package here will make a brief reference to these programs. Data warehouse and applications that are based on it are the result of the efforts that all information relevant to the functioning of businesses unite in one, for (of speaking) of each access point. If the user data on its sale of holding in Excel it is perhaps easy, but they can not be integrated with other information such as sector (ie, least not without the intervention of each of these users manually re-enter, copy + paste određeneih parts which decides integrated, ie Popćeno action dependent on customer service this spring). So the summary report for a company always at the request must work again, which is the objective circumstances (the presence of all persons who are required to do so, updating of data, etc.) means that the report came much later (perhaps too late), but if the data on one place (in the data warehouse) came to their synthesis is concerned computer. Excel as the application can be helpful in the extreme view of some data and prepare them for eventual printing and presentation rather than as a tool to interactively look at these data because it was not intended.

More:

Benefits of Data Warehouse (Part1)

Benefits of Data Warehouse (Part2)

Benefits of Data Warehouse (Part3)