DB Ch2 Flashcards
Why the network replaced the hierarchical mode ?
Because the former made it much easier to represent complex .
What is the advantage of the relational model ?
Simpler data representation
To use query language
What is the example of the conceptual model ?
ER
What is the example of the implementation model ?
Network
Hieratical
What is the models that can be the conceptual and implementation ?
Relation
OO
What is the external model ?
Is the end user view of the data environment
What is the conceptual schema ?
It is the basis for the identification and high level description of the main data objects
What is the def of the ER?
The basic database blueprint
What is the logical design ?
is used to refer the task of creating a conceptual data model that could be implemented in any DBMS
what is the internal model ?
is the representation of the database as seen by DBMS
true or false ?
when you can change the internal model without affecting the conceptual model you have logical independence
data abstraction model
https://images.app.goo.gl/YG4ewP4ZaSPYNxoe7
