Test 1 (Notes) Flashcards
What’s the smallest unit of data on computing?
A bit
In a data repository, you have:
- Tables (which represents entities/events)
- Columns rows
- DB
What is the input of conceptual modeling or conceptual schema?
User requirements
What are the steps to conceptual modeling?
- Conceptual Modeling (ER model)
- Logical Modeling (Relation)
- Physical Model
- Implementation
- Testing and Installation (Target DBMS Selection)
In conceptual modeling, there are two important things we have to do, what are they?
- Defining data objects (also known as entities)
- Documenting business rules
What is a degree of a relationship?
Number of entities that participate in a relationship. Ex - binary, unary, etc.
What is a cardinality of a relationship?
Number of instances in an entity. Ex - one-to-one, one-to-many, many-to-many, etc.
What’s a super type entity?
A generalization of an entity (ex - vehicle)
What’s a sub type entity?
Specialization of a vehicle (ex - SUV, truck, etc.)
What is a relation?
Single data structure (ex - table)
What is an attribute?
Named column of a table
What is a tuple?
A row of relation
What is a degree?
Number of columns found
What is a cardinality?
Number of tuples found
What is domain?
Strings or integers
