Exam (elaborations)
ISA 245 Exam 2 With 100% Correct And Verified Answers
- Module
- Institution
ISA 245 Exam 2 With 100% Correct And Verified Answers
[Show more]
Seller
Follow
Vendarsol
Reviews received
Content preview
ISA 245 Exam 2 With 100% Correct AndVerified Answers 2024-2025
Boyce-Codd Normal Form (BCNF) - Correct Answer-A special type
of third normal form (3NF) in which every determinant is a
candidate key.
Candidate key - Correct Answer-An attribute, or combination of
attributes, that uniquely identifies a row in a relation.
Fourth Normal Form (4NF) - Correct Answer-In 3NF and contains
no multiple independent sets of multivalued dependencies.
surrogate key - Correct Answer-A system-assigned primary key,
generally numeric and auto-incremented.
De-normalization - Correct Answer-The process of splitting or
combining normalized relations into physical tables based on
affinity of use of rows and fields. (intentionally adds redundancy)
Why do we need to consider de-normalization? - Correct Answer-
improves query performance, processing speed, makes reports
easier
multivalued attribute - Correct Answer-An attribute that may take
on more than one value for a given entity (or relationship)
instance.
Data Definition Language (DDL) - Correct Answer-DBMS language
that builds the data dictionary, creates the database, describes
logical views, and specifies record or field security constraints
(ex. creating a table, creating a view, etc.)
Vendarsol
,Data Manipulation Language (DML) - Correct Answer-DBMS
language that changes database content, including data element
creations, updates, insertions, and deletions (SELECT, UPDATE,
INSERT, DELETE, COMMIT, ROLLBACK)
Can you update a constraint? - Correct Answer-NO! We must drop
the constraint and add a new one instead
Adding new constraints - Correct Answer-ALTER TABLE
tablename
ADD (constraint)
CHECK
Inserting a record - Correct Answer-INSERT INTO table VALUES()
rowid - Correct Answer-internally assigned by the system
DROP vs DELETE. - Correct Answer-DROP: DDL that affects the
schema and cannot be rolled back. Deletes the entire table!
DELETE: DML that affects the data only and can be rolled back.
Deletes only the contents of the table while maintaining the
structure
COUNT(*) vs COUNT - Correct Answer-Count
all values, including null
Count just the non-null values
disable - Correct Answer-make unable to
perform a certain action
Vendarsol
, entity supertype - Correct Answer-A generic
entity type that contains the common
characteristics of the entity subtypes.
entity subtype - Correct Answer-contain the
unique characteristics of each entity
entity supertype vs entity subtype - Correct
Answer-A subtype is the subset of the entity
supertype. The supertype is more common
characteristics and the subtype is more
unique characteristics
specialization hierarchy - Correct Answer-
based on grouping unique characteristics and
relationships of entity subtypes
entity cluster - Correct Answer-temporary
entity used to represent groups of related
entities and relationships within a database
model. ("virtual" or "abstract" -not a real
entity type in the final ERD)
Why do we sometimes need to use entity
cluster in an ER diagram? - Correct Answer-
simplifies the ERD and enhances its
readability
Vendarsol
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Vendarsol. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £14.79. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
72042 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now