MC Which statement is CORRECT? The fact that most NoSQL databases adopt an eventual consistency approach is due to the CAP theorem, which states that strong consistency cannot be obtained when availability and partitioning has to be ensured. correct Stabilization relates to the waiting time between the start-up of a NoSQL system and when the system becomes usable to receive user queries. incorrect Some relational constructs, such as the many-to-many relationship, are harder to express using graph databases. incorrect Replicas in a distributed NoSQL environment relate to making periodic backups of the database to a second system. incorrect
MC Which statement is NOT CORRECT? Edges in graphs can be uni- or bidirectional. incorrect Graphs are mathematical structures consisting of nodes and edges. incorrect Graph models are not capable to model many-to-many relationships. correct Graph databases work particularly well on tree-like structures. incorrect
MC Which statement is NOT CORRECT? Graph models are not capable to model many-to-many relationships. correct Graph databases work particularly well on tree-like structures. incorrect Graphs are mathematical structures consisting of nodes and edges. incorrect Edges in graphs can be uni- or bidirectional. incorrect
MC Which of the following is not an example of a NoSQL database? Graph based databases. incorrect XML based databases. incorrect Document based databases. incorrect All three can be regarded as NoSQL databases. correct
MC Which statement is NOT CORRECT? Edges in graphs can be uni- or bidirectional. incorrect Graph models are not capable to model many-to-many relationships. correct Graph databases work particularly well on tree-like structures. incorrect Graphs are mathematical structures consisting of nodes and edges. incorrect
MC Using Cypher, how do you get a list of all movies Wilfried Lemahieu has liked, when he has given at least four stars? MATCH (b:User)-[I:LIKES]-(m:Movie)
WHERE b.name = "Wilfried Lemahieu"
AND m.stars >=4
RETURN m incorrect SELECT (b:User)--m:Movie)
WHERE b.name = "Wilfried Lemahieu"
AND m.starts >= 4 incorrect MATCH (b:User)--(m:Movie)
WHERE b.name = "Wilfried Lemahieu"
AND l.stars >= 4
RETURN m incorrect MATCH (b:User)-[I:LIKES]-(m:Movie)
WHERE b.name = "Wilfried Lemahieu"
AND l.stars >= 4
RETURN m correct
MC Which of the following statements describes NoSQL databases best? NoSQL databases are non-relational. correct NoSQL databases are not capable to deal with large datasets. incorrect A NoSQL database offers no support for SQL. incorrect NoSQL databases do not support joins. incorrect
MC Using Cypher, how do you get a list of all movies Wilfried Lemahieu has liked, when he has given at least four stars? MATCH (b:User)-[I:LIKES]-(m:Movie)
WHERE b.name = "Wilfried Lemahieu"
AND l.stars >= 4
RETURN m correct SELECT (b:User)--m:Movie)
WHERE b.name = "Wilfried Lemahieu"
AND m.starts >= 4 incorrect MATCH (b:User)-[I:LIKES]-(m:Movie)
WHERE b.name = "Wilfried Lemahieu"
AND m.stars >=4
RETURN m incorrect MATCH (b:User)--(m:Movie)
WHERE b.name = "Wilfried Lemahieu"
AND l.stars >= 4
RETURN m incorrect
MC What does the following Cypher query express?
OPTIONAL MATCH (user;User)-[:FRIENDS_WITH]-(friend;User)
WHERE user.name = "Bart Baesens"
RETURN user, count(friend) AS NumberOfFriends Get the node for Bart Baesens and a count of all his friends, even if no FRIENDS_WITH relation exists. incorrect This query will fail if Bart Baesens is FRIENDS_WITH himself. incorrect Get the node for Bart Baesens and all his friends. incorrect Get the node for Bart Baesens and a count of all his friends, but only if at least one FRIENDS_WITH relation exists. correct
MC Which of the following is not an example of a NoSQL database? Graph based databases. incorrect XML based databases. incorrect Document based databases. incorrect All three can be regarded as NoSQL databases. correct