Speak XV:
1. First Paradigm: i.e., each component is not decomposed, uncomplexed and multivalued attributes property
2. Second paradigm: the first normal form, and each non-primary property must be entirely dependent on the candidate key
Depends in part on: i.e. non-primary key attribute depends on the subset of candidate
3. Third Pattern: i.e. second normal form, and rely on pass absent
Because nontrivial dependency is not satisfied, it is not counted as dependent transmission, the third normal, but dependent on the second side does not contain the candidate decision key, it can not be regarded BCNF
4.BCNF: That is to rely on the properties of all candidate keys
The multivalued dependency: i.e. x + y-> z, when changing the value of y, or can be established, said x -> z
6. Fourth Paradigm: non-primary property does not exist, other than the candidate key multivalued attribute depends necessarily in BCNF
7. weak fourth paradigm: ?
Analysis of the wrong question:
Analysis: candidate key in question may be, {A}, {B}, must be first third normal form, and secondly, being dependent only candidate key
Speak XVI
1. What is the mode decomposition:
Mode decomposition during our time to pay attention to its lossless connectivity (content does not change) and kept dependent (dependent change will not happen).
2. How to connect non-destructive inspection:
If the new relationship after the relationship with the original set of decomposition of natural connection tuples obtained exactly the same, it is called lossless join
3. What remains is dependent decomposition:
Formerly dependent on all members of a set which does not reduce
4. What is dependent on the connection:
5.5NF
6. General database requirements:
Generally only meet up to BCNF
