Data Cardinality — Learn free

Self-check

Questions 1–10 of 10

1. What is Data Cardinality about?
Question 1A. The physical size of a table on diskB. Maintaining the level of details in a tableC. The number of users who can query a tableD. The encryption applied to a columnE. The order in which rows are stored
2. What is High Cardinality?
Question 2A. When a table has a high number of duplicatesB. When a table has many columnsC. When there are no or few duplicates in a tableD. When a table has many foreign keysE. When a table is very large
3. Which kind of table is mostly in Low Cardinality mode?
Question 3A. Tables with a primary keyB. Tables with a foreign keyC. Empty tablesD. Lookup tablesE. Temporary tables
4. In the Product and Sales example, why does the Sales table have Low Cardinality with respect to Products?
Question 4A. Because it has no primary keyB. Because Product names are stored in itC. Because it stores fewer rows than the Product tableD. Because Sales rows are deleted dailyE. Because one product can be sold many times, so Product ID repeats across many rows
5. On what basic concept is normalisation said to depend?
Question 5A. EncryptionB. CompressionC. IndexingD. PartitioningE. Cardinality
6. Why can we NOT say that all primary key tables have absolute highest cardinality?
Question 6A. Because primary keys can be nullB. Because cardinality only applies to fact tablesC. Because primary keys are only used in OLAPD. Because tables with a foreign key can also have a primary key and become the primary table for another foreign key tableE. Because duplicates are always allowed in primary tables
7. Which of the following is NOT one of the three degrees of cardinality?
Question 7A. One to One (1:1)B. One to Many (1:M)C. Many to Many (M:N)D. Many to None (M:0)E. All of these are degrees of cardinality
8. What does a One to Many (1:M) relationship mean?
Question 8A. A single row in table A relates to many rows in table BB. A single row in table A relates to a single row in table BC. Many rows in table A relate to many rows in table BD. Table A has no relationship with table BE. Table A and table B are the same table
9. What can happen when tables are joined using the wrong columns, without direct primary and foreign key relationships?
Question 9A. The query runs fasterB. The result is automatically deduplicatedC. The result can end up as Cartesian dataD. Cardinality increasesE. Foreign keys are created automatically
10. When a table structure changes for a business requirement, what is the first question to ask, and what helps trace the impact?
Question 10A. Whether the change affects cardinality; Data Lineage, backed by Metadata Management, shows the end-to-end impactB. Whether the change affects disk space; the DBA shows the impactC. Whether the change affects colour schemes; the BI tool shows the impactD. Whether the change affects licensing; the vendor shows the impactE. Whether the change affects network load; the firewall shows the impact