Which of the following about JOIN operations is/are correct?Question 9Select one or more:Select one or more:a.The lack of JOIN operations in a NoSQL database leads to the issues of data redundancy and data integrity.b.MongoDB supports a JOIN operator, similar to relational databases.c.The JOIN operations are essential for developing efficient autosharding technologies.d.The JOIN operations are not common in NoSQL databases because they could make the query processing slow.

In relation to a Graph Database which of the following are correct?试题 5选择一项或多项：a.Compared with key-value data stores, graph databases generally have more complex data models but are less scalable.b.Neo4j does not support the join operation.c.In a graph database we represent data in terms of graphs having two fundamental units being nodes and relationships and while noes may have properties relationships are not allowed to have properties.  d.Graph databases can navigate through graphs to answer queries, and thus they always provide a better performance for queries than relational databases.

Which of the following is/are correct?Question 4Select one or more:Select one or more:a.Some NoSQL databases let the programmer decide the trade-off between scalability and consistency.b.Different NoSQL databases may offer different levels of transaction supports.c.There are no transactions in any NoSQL databases.d.NoSQL databases define isolation levels under the BASE model .

(40-60 words) in response to each of the following questions.Why do you think JOIN statements are important for working with databases? What are the consequences of choosing the wrong type of JOIN for your application?For what types of activities will aliasing be most useful?

What is/are the reason(s) for considering a NoSQL database, rather than a relational database?Question 8Select one or more:Select one or more:a.Complex transactions can be performed to preserve consistency across difference transactions.b.A database can allow the insertion of data without a pre-defined schema.c.High-performance queries are needed over a large amount of data, while update operations are rare.d.A declarative query language is preferred for querying data and managing data integrity.

Which of the following are characteristics of NoSQL databases? Select all that apply. 1 mark is deducted for each incorrect choice.Question 2Select one or more:A.Complex query supportB.Eventual consistencyC.ACID transactionsD.Strong consistencyE.Limited horizontal scalabilityF.Horizontal scalingG.Distributed computingH.High availabilityI.Schema-free designJ.Complex joins