In the context of a data warehouse, ETL stands for:
- A.Encrypt, Transfer, Link
- B.Extract, Transform, Load
- C.Enter, Test, Launch
- D.Evaluate, Train, Learn
Correct answer
Explanation
The correct answer is B, Extract, Transform, Load. ETL names the three steps through which data enters a warehouse: it is extracted from the operational systems that produced it, transformed so that formats, units, codes and duplicates are reconciled into one consistent shape, and then loaded into the warehouse tables. Where the loading is done before the transformation, as often happens with a data lake, the arrangement is called ELT instead. Option A is wrong because encryption and transfer belong to data security and networking, not to warehousing. Option C is wrong because entering, testing and launching describe the stages of software release. Option D is wrong because evaluating, training and learning describe how a machine learning model is built, a later use of the data rather than the pipeline that fills the warehouse.
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Practice Questions
View allA central repository of information that can be analyzed to make more informed decisions is known as:
- A.Data mining
- B.Data storing
- C.Data sorting
- D.Data warehouse
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A data warehouse is exactly that, a central store into which data from many operational systems is extracted, cleaned and loaded so that it can be analysed for decision making.
Read the full explanation →Which of the following statement(s) is/are correct regarding On-Line Transaction Processing (OLTP)? I. Responses to the user inquiry are immediate. II. The associated cost is economical with efficient utilization of resources. III. The database is always up-to-date.
- A.Only II
- B.I and III
- C.I and II
- D.Only III
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On-Line Transaction Processing is the mode in which a bank counter, a railway booking window or a payment gateway works: each transaction is processed the moment it is entered, so the response to the user is immediate, and every committed transaction is written at once, so the database always reflects…
Read the full explanation →Which of the following is NOT one of the three Vs of big data?
- A.Volume
- B.Velocity
- C.Variety
- D.Virtualisation
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Virtualisation is the technique of running several logical machines on one physical machine and belongs to the chapter on cloud computing, not to the definition of big data.
Read the full explanation →In Hadoop, which component is responsible for storing data across the machines of a cluster?
- A.MapReduce
- B.HDFS
- C.YARN
- D.Hive
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It splits a large file into fixed-size blocks, 128 megabytes by default in current versions, scatters those blocks over the machines of the cluster and keeps more than one copy of each block so that the failure of a machine does not lose data.
Read the full explanation →Data mining is best described as which step of the knowledge discovery process?
- A.The collection of raw data from sensors
- B.The step that finds patterns in prepared data
- C.The backing up of a database
- D.The printing of a management report
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In the process called Knowledge Discovery in Databases, or KDD, the stages run from selection of the relevant data, through cleaning and preprocessing, to transformation, then data mining, and finally interpretation and evaluation of what was found.
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