produces a lower normal form; results in increased performance and greater data redundancy
Anomalies
insertion, deletion & update
Functional dependence
when one attribute is dependent on another;
student ID - student name
Determinant - dependant
Fully/partial functional dependence
it can only exist where there is a composite PK (the combination of 2 PKs).
If an attribute (student grade) is dependent on both attributes from the PL (student ID & class ID) then we call it fully functionally dependent. If an attribute depends only on one of the PK then it is partial.
Transitive dependency
is when an attribute is dependent on another attribute (that is not a part of the PK); also known as non-key to non-key
1NF characteristics
no repeating groups; in this table, those are emp number, emp name, etc.
First we need to break emp num into a separate row
2 NF
required: table has to be in 1NF and no partial dependency
In this case, if we know a proj num, we know the project name; this is partial dependency.