The process of where a data warehouse is fed with extracted source data is largely known as ETL (Extraction, Transforming and Loading). ETL is a critical process in the construction of a data warehouse project.
The three stages of the ETL process comply of:
Extraction: Data is identified and extracted from one or more external different sources, including applications and database systems.
Transform: Data is transformed in the aim of ensuring consistency and satisfying business requirements.
Loading: Data is loaded into the resultant data warehouse.
There are many challenges involved with fulfilling a dependable ETL process. Some of these relate to:
Data volumes – as there are huge amounts of data available presently,
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Throughout extraction, the desired data is identified and extracted from the source system and is made available for additional processing. The data can be extracted from numerous different sources. In most cases, the data sources are internal however sometimes they are external. The ultimate aim is to retrieve all the essential data from the source system with as little resources as possible. The size of the data extracted can range from kilobytes to gigabytes.
For extraction within the ETL to be positive and effective, it is essential that there is a high understanding of the data’s layout. The data should also be backed up in another location. Sometimes, it isn’t possible to identify the exact subsection of interest, as a result a larger amount of data than needed has to be extracted. Consequently, the identification part of extract is carried out further down the line within the ETL process. Depending on the competence of the system, transformations can take place during the extraction stage of ETL.
The difficulty of the extraction step is dependent on how alike or unalike the source systems are and the type of source data. Good documentation along with excellent maintenance and the use of similar technology within a system should result in fairly simple extraction process. On the other hand, poor documentation and incompetent maintenance using different formats of data and technologies will result in
Data in computerized form is discoverable, even if the paper “hard copies” of the information have been produced. The producing party can be required to design a computer program to extract the data from its computerized business records.
Extraction, Transformation, and Loading processes are responsible for the operations taking place in the back stage of a data warehouse architecture. In a broader aspect, initially the data is extracted from the source data stores which could be On-Line Transaction Processing or Legacy system, files of any formats, web pages or any other documents like spreadsheets or text documents. In this step, only the data which is different from the previous execution of ETL process (newly inserted, updated) gets extracted from the sources. Next, the extracted data is sent to Data Staging Area where the data is transformed and cleaned. Finally, the data is loaded to the central data warehouse and all its counterparts e.g., data marts and views. (Kabiri & Chiadmi 2013, p.1)
24) Before it can be loaded into the data warehouse, operational data must be extracted and
Extraction: This is the process of extracting any evidence that is found relevant to the situation at hand from the working copy media and subsequently saved to another form of media as well as printed
In order to extract the information I require and want I utilize the following methods;
Specialized techniques for data recovery, evidence authentication and analysis of electronic data far exceeding normal data collection and preservation
The databases are required to be accessed very properly; the broken or fragmented data needs to be recovered. For querying and reporting purposes the data should be easily accessible
Most of the time we might have to clean and process the data to find some hidden insights in the data. This is called data processing.
Information collected digitally from computers or media storage applications has protocols that need be followed during the process. The order of collecting digital information mostly determines the life expectancy of information collected (Eoghan, 2004, p. 74). There is a need to change information
imaging application. This is because the crucial data required for the classification phase are derived at this stage. Feature extraction is the process of estimating
The data information also included the component of the data collection, the operational definition, the type of analysis, and the location in the program file.
Chapter 2 describes the Avalon data warehouse functionality and chapter 3 the scope of the Avalon data warehouse. Chapter 4 lists the motivation for supporting the Avalon data warehouse implementation. In chapter 5, the process of collecting and processing business requirements is described. At chapters 6 and 7, there is a technical description of the architecture and data security, and Chapter 8 outlines the implementation plan.
As the reader has got now all the information available about theory and methodology, it’s time to move on to the concrete part. Indeed, next header explains the extraction of data.
The data file consists of lots of entities, which needs to extract the data according to the given format. And to do the analysis, an algorithm is developed according to the hierarchy as given in the excel worksheet, and a graphical user interface (GUI) to visualize the output of data.