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Data Warehouse : Database Analysis And Query

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DATA WAREHOUSE: OVERVIEW: Data warehouse is a central repository integrating data from various operating systems for validation of data, prediction etc .Data Warehouse is a relational database used for analysis and query rather than transactional database. It is used to collect historical data from various sources, integrate, analyze a particular subject, report. Data warehouse is time variant i.e one can retrieve any older data and once data enters data warehouse it cannot change [1]. According to Ralph Kimball Data warehouse is “copy of transaction data constructed for analysis and query”[5]. Data is taken from various sources like marketing, sales, ERP etc. Data warehouse data is different from operational data as it is subject …show more content…

EXTRACTION, CLEANSING AND TRANSFORMATION TOOLS It is a process in database usage particularly in data warehouse where data is extracted from various sources, transformed into a particular look or format and then loaded into the target. All these three process run at a time as the extraction process takes much time all the process run simultaneously. Data can be extracted from relational and non-relational databases. One of the natural things in extraction is that data validation is done to check if the data is related or not [9]. The important function of transformation is that cleansing of data i.e it forwards only the proper data. As the character set differs from system to system communication among them is very important. Before loading of the data some tasks like indexing, partitioning needs to be done and then we can load the data using data loaders into the data warehouse [7]. Loading of data depends upon the type of data warehouse selected on the requirements of corporation. ETL process can be done as separate products or can be integrated which may be of the category Code generators which creates the programs depending on the target definitions. It can be of the category database data replication tools which apprehends the changes in the data and applies these changes to data present in different location. DATA QUALITY Data quality is an important factor in accurately

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