IS 201 Flashcards
IS 201 1st Big Quiz (27 cards)
GIGO
Garbage in, garbage out
What makes good data? (list)
Accuracy
Completeness
Consistency
Timeliness
Validity
Uniqueness
Relevance
Reliability
Accessibility
Accuracy
Is it correct information?
Double-check information using controls
Limit what can be input to a reasonable range (0<age<140)
Send a verification email when someone signs up with an email
Completeness
Is all the information there?
Controls:
Require certain fields
Can be harder than accuracy since some people may not respond
Consistency
Does are data the same everywhere?
E.g. Utah, utah, UT, ut, Ut, UTAH, Uth(typo)
Controls:
Database Design
Dropdowns, radio buttons, checkboxes instead of free text fields
Timeliness
Do we have our data when we need to have it and does it represent the time period we need to make a decision?
Validity
Related to accuracy. Does our data represent what we think it does?
E.g. fake@fakeemail.com is a valid email (has @, .com, and other text) but not (probably) and accurate one
8-867-5309 is not a valid US phone number
Controls:
User Input
Uniqueness
Are we storing the data once and only once per piece of data?
Controls:
Database Normalization (will talk about later)
Relevance
Can we use this data to make the decision we are making?
Controls:
Asking the right questions
Asking only one question at a time
Using a good measuring scale
Measure what you want to measure and not something else
Reliability
Can we rely on this data for our decision?
Controls:
Controlling for the other aspects of data quality will help with this one
Accessibility
Can the right people access the data when they need to? (More discussion on this in security section)
Controls:
User Permissions
UI design
UX design
Correct data format for the user
Fine to Coarse scale
Aggregate=>Summary=>Detail
Databases (Ordered by Quality)
Paper
Text Document
Excel
Database Management System (DBMS)
Transactional VS Analytical
Transactional
Day-to-day operations generate and consume this type of data
Used in operation so stored in an |Operational| database
Analytical
Insight used to gain strategic advantage
Used in analytics so stored in an Analytical database
Satisficing meaning?
Good Enough info, worth the cost idea
ERD
Entity Relationship Diagramming
vocabulary table
Views
simple, expanded, full
Where do Foreign Keys go?
1:M
the primary key of the 1 side becomes a foreign key on the M side
1:0
the primary key of the required side becomes a foreign key on the optional side
1:1
Doesn’t matter, pick either one to receive the FK
Many > Optional > 1
Serializable vs. non-serializable
Serializable - has own ID number, transferable
Cars, guns, etc.
When you need to keep track of specific products
Non-serializable (General/Virtual) - no ID, don’t care if transferred
Toilet paper, food, most items at grocery store
Serialized item: can belong to at most, a single order
Non-serializable (General/Virtual item): can belong to at most, many orders
Order of SQL statements
SELECT - REQUIRED
FROM – REQUIRED
JOIN
WHERE
GROUP BY
HAVING
ORDER BY
Semantic Key
Also known as a “natural” key, a semantic key is a key for which the values have an obvious meaning to the user of the data (e.g., ‘USA’ for a country code).
Artificial Key
A key that has no obvious or inherent meaning to the user. It serves the purpose of uniquely defining each row (e.g., ORDER_ID, INVOICE_ID).
Composite Key
A key that contains more than one attribute.
