ETL (Extraction Transformation Loading) Process In Data warehousing:
When we do software development we have different stages like requirement gathering, designing, coding, testing. Similarly we have some steps in data warehousing also.
There are three stages in data warehousing:
1. Extraction
2. Transformation
3. Loading
In details of these three stages
1. Extraction: In this process we can extract the data from the source. In real time scenario the source files may be Excel,Access,Delimited text,CSV files,etc., so extraction involves understanding of data source and loading that into a structure of data warehouse.
2.Transformation: In this stage the data can be cleaned .in this source files the data is not in good format so in this stage the data will be formatted as per the client requirement.Its not necessary that after extraction process data is clean and valid.For instance all the financial figures have null values but you want to be ZERO for better analysis.so you can have some kind of stored procedures which returns through all the records and sets the value to zero.
3.Loading: After Transformation you are ready to load the information in to your final data warehousing data base.
When we do software development we have different stages like requirement gathering, designing, coding, testing. Similarly we have some steps in data warehousing also.
There are three stages in data warehousing:
1. Extraction
2. Transformation
3. Loading
In details of these three stages
1. Extraction: In this process we can extract the data from the source. In real time scenario the source files may be Excel,Access,Delimited text,CSV files,etc., so extraction involves understanding of data source and loading that into a structure of data warehouse.
2.Transformation: In this stage the data can be cleaned .in this source files the data is not in good format so in this stage the data will be formatted as per the client requirement.Its not necessary that after extraction process data is clean and valid.For instance all the financial figures have null values but you want to be ZERO for better analysis.so you can have some kind of stored procedures which returns through all the records and sets the value to zero.
3.Loading: After Transformation you are ready to load the information in to your final data warehousing data base.
goo posting and clear explanation .thank you so much
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