E-R Diagrams
SQL supports _______ which could be used to for instance find all the prerequisites of a
course (the immediate prerequisites, their prerequisites, and so on) or all superiors of an employee
(the immediate supervisor, their supervisor, and so on).
recursive queries
JSON is a textual representation of _____ including objects and arrays
non-atomic data,
It can be time-consuming to interface with a relational database from an object-oriented
programming language due to the conversions needed between....
objects and relations
______ is a object-oriented database that stores all information as JSON/BSON.
MongoDB
______ systems typically make use of a large number of relatively cheap computers
Give an example of one
Distributed file, Hadoop File System
What is the procedure for converting an ER diagram to a collection of relation schemas?
a. Most entity sets become relations
b. Multivalued attributes become relations with primary key that is the union of the entity key plus
the attribute.
c. Some relationship sets might become relations, but some might be redundant, such as
i) Identifying relationship for a weak entity
ii) Relationship that has no attributes and that has a “many” side with total participation:
represented by including primary key of the other side of the relationship as a non-key
attribute in the many-side relation schema
d. Primary key of a relationship set schema is the union of the primary keys of the entities in the
relation
BSON provides______ representation of JSON
compressed, more computationally efficient
Three approaches to lessening the mismatch between object-oriented programming and relational
databases are
a. Object-relational databases
b. Object-relational Mapping (ORM) software
c. Object-oriented (NoSQL) databases
Big Data systems are characterized by
a. High volume of data
b. High velocity of data insertion
c. High variety of data, beyond relational data
_____ is typically done based on the value of an attribute, such as user ID or zip code
Sharding
A well-designed ER diagram properly reduced to relation schemas will likely not need any
normalization
Db2 stores JSON as BSON using the ___ data type
BLOB
The object IDs of an ______ are only unique within a given table. This means that
a reference to an object in such a database must specify both the table and the object ID.
Object-relational Database
Big Data storage systems can take different forms:
a. Distributed file system
b. Sharding of database tables
c. Key-value storage
d. Parallel and distributed databases
______ tend to be used when there are very many records of relatively small size.
Key-value stores
______ is sometimes used for performance reasons, e.g., to avoid frequent joins
Denormalization
Db2 allows BSON data to be ______ attribute values to be.....
queried, retrieved
Object-relational databases often support _____ of table types
inheritance
As the number of machines in a system increase....
the chance of at least one machine going down
also increases.
In making the CAP tradeoff in the presence of a network partition, traditional databases tend to
choose _____, web applications to choose______
consistency over availability, availability over consistency
Normalization does not guarantee that a database design is good. Some normalized databases with
bad design include:
a. Having one earnings table per year (earnings2020, earnings 2021, etc.)
b. Having one earnings attribute per year in a table (earnings(year2020, year2021, etc.)).
Many configuration files are written using
XML
________ is a Java ORM.
Hibernate
Since Big Data systems use multiple machines, these systems all tend to use _____ to
improve system availability.
replication
All database systems have multiple types of physical storage because of differences in
a. Speed
b. Cost
c. Reliability