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What is ETL?
Extract – Extracting the data from source system
Transform – Transforming or modifying the data into format what business required
Load – Loading into target database
Explain about your current project?
Here explain about your current project with clear ETL process, practice before getting into an interview room.
Start with what is the objective of the project whether building a data mart or warehouse or ODS.
Then, explain how many source systems are there and do you have staging environment or not.
Then, tell about the ETL tool you are using. Stop it here.
What are the transformation types?
The output record count of the transformation may or may not equal to input record count.
For example, when we apply filter transformation for age column with the condition of age between 25 and 40. In this case, the data will come out which satisfies this condition, hence the outcome count cannot be predicted.
The output record count of the transformation is equal to input record count.
For example, when we apply expression transformation to concatenate first name and last name columns, in this case, the data will come out even though the columns do not have values.
A transformation which is being linked with other transformation or target component is called connected.
A transformation which is not being linked with any other transformation or target component is called unconnected.
What are the types of load?
The data loading process when we do it at very first time. It can be referred as Bulk load or Fresh load.
The job extracts entire volume of data from source table or file and loading into truncated target table after applying transformations logics
Incremental Load (Refresh Load or Daily Load or Change Data Capture) –
The modified data alone will be updated in target followed by full load. The changes will be captured by comparing created or modified date against last run date of the job.
The modified data alone extracted from the source, the job will look for changes in the source table against job run table, if change exists then data will be extracted and that data alone will be updated in the target without impacting the existing data.
Name some ETL tools
Informatica Power center
Talend Open Studio
SQL Server Integration Services (SSIS)
Oracle Data Integrator
SAS – Data Integration Studio
SAP – Business Object Integrator
Pentaho Data Integration
What are the components of Informatica?
One of the major tool in worldwide. Majorly this tool is using for ETL, data masking, and data quality.
It has four major components,
Repository manager – to add repository and managing folders
Designer – creating mappings
Workflow manager – creating workflow with task and mappings
Workflow monitor – workflow run status tracker
What are tasks available in Informatica?
The below are major tasks available in Informatica power center tool.
What is partitioning?
Portioning is a concept of running with parallel threads by distributing records. It will be used when the volume of data is huge which directly impact the data load and other transformation progress.
Database and ETL tools are offering this partition concept to improvise the job execution time for high volume data tables.
Below are the types of partitioning available in Informatica power center tool,
5.Hash Auto key
6.Has user key
Now, you can watch the ETL Concepts, ETL Tools Interview Questions and Answers in YouTube videos, CLICK HERE
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