Week 1: ER Diagrams Flashcards
What is data?
Known facts that can be recorded and have an implicit meaning.
What is a database
A collection of related data
What is a mini-world?
A database is a model of a mini world. Some part of the real world about which data is stored in a database. E.g. medical office, a retail business, a library are all mini worlds
What is a DBMS
A software package/system to facilitate the creation and maintenance of a computerized database.
What is a Database system
What is a flat file?
a .txt or an ASCII file
What is a record/instance?
One row of a flate file
What is a DBMS and what are its advantages over flate file system
What is a database administrator? What are their responsibilities?
What is a Database Designer? What are their responsibilities?
What are system analysis and application programmers? What are their responsibilities?
What is an end user? Responsibilities?
What is a database schema?
What is a database instance?
What is a database state/snapshot?
What is the 3 schema architecture?
What is the difference between logical data independence and physical data independence?
- When starting a project, you should always start with …
- Narrow your ___ as much as possible and figure out what data you need to store/save by…
What model do we use to represent a database before creating it? Who made it?
When designing a DB, pay attention to..
NOUNS
What are the following:
Entity
Attribute
Value
Composite Attribute vs. Atomic attribute
Single-valued attribute vs. multi-valued attribute
Derived attribute vs stored attribute
What are the following:
Entity type
Entity
Entity set
Key, uniqueness
Value Sets
How are the following represented in ER diagrams?
Entity type
Attribute
Key attribute
Multi-valued attribute
Composite attribute
Derived attribute
What are the following:
Relationship
Relationship set
A relationship Type R
Example of binary, ternary, and unary relationships
What are the following
Recursive relationship
Attributes on relationships
Cardinality ratio
How are the following represented in ER diagrams?
Relationship type
Relationship attribute
Cardinality
What is participation constraint?
Total participation?
Partial participation?
(min,max) notation?
How are relationship participations and (min,max) notation represented in ER diagrams?
What is a weak entity? How are they represented in ER diagrams?
In ER diagrams what is the naming convention?
How are entities represented in crow’s feet notation?
How are relationships represented in crows feet notation?
