COLUMNAR (WIDE-COLUMN) DATABASES — Learn free

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Questions 1–10 of 10

1. How do wide-column databases organise data?
Question 1A. Into rows and dynamic columns grouped into column familiesB. Into fixed-schema rows where every row has the same columnsC. Into nodes and edgesD. Into key–value pairs with opaque valuesE. Into a single-rooted tree of parent–child records
2. What is the primary goal of wide-column databases?
Question 2A. Guaranteeing strict relational consistencyB. Enabling high write throughput and scalable query performance over massive volumes of dataC. Storing behaviour alongside dataD. Supporting semantic reasoningE. Minimising the number of tables
3. Which workloads are wide-column databases particularly well suited to?
Question 3A. Small single-user desktop applicationsB. Ad-hoc cross-entity analyticsC. Time-series, event-driven and high-velocity workloadsD. Complex multi-table reportingE. Rule-based reasoning over ontologies
4. How is data placed in a wide-column database?
Question 4A. Spread randomly across nodes to balance loadB. Normalised into separate entity tablesC. Stored in one document per entityD. Partitioned by a primary key, with all related data for that key stored together in a partitionE. Stored as an append-only event log
5. In the Cassandra loan example, what is the partition key and why?
Question 5A. LoanID, so that each loan is stored separatelyB. OfficerID, so that officers can review their queueC. ApprovalDate, so that loans are ordered by timeD. Branch, so that branch reports are fastE. CustomerID, so that all loans for a customer reside together
6. How are repayment amounts represented in the wide-column loan example?
Question 6A. As flattened columns such as Repayment_2024_02 and Repayment_2024_03 within the partitionB. As a separate Repayment table joined by LoanIDC. As an array inside a JSON documentD. As edges between Loan and Payment nodesE. As RepaymentMade events in a stream
7. What shapes the schema of a wide-column database?
Question 7A. Functional dependencies between attributesB. The expected access patterns and the specific queries to be answeredC. Class hierarchies and inheritanceD. Domain and key constraintsE. The order in which events occur
8. Which of the following is NOT listed as a trade-off of wide-column databases?
Question 8A. Query patterns must be known in advanceB. Complex joins across partitions are impracticalC. Poor write throughput under heavy loadD. New query types may require schema redesignE. Limited flexibility for ad-hoc analytical queries
9. For which kind of environment are wide-column stores best suited?
Question 9A. Environments needing flexible cross-entity analyticsB. Environments with constantly changing query requirementsC. Environments requiring complex relational reportingD. Large-scale, high-velocity environments where workloads are predictable and performance is criticalE. Environments where behaviour must be stored with data
10. In the comparison of relational and columnar models for loan approval, how is the columnar model characterised?
Question 10A. Normalised, flexible and consistent, but with costly joins at scaleB. Fully normalised with dimensions for Customer, Officer and RepaymentC. Optimised for ad-hoc joins across customersD. Stored as one JSON document per loanE. Denormalised, partitioned and built for high-volume throughput and predictable queries