Test about database security P5

Unable to, because the key value is unknown

Can insert

Impossible, because of information conflicts.

Impossible, because of information anomalies

Does not exist X Y F ⁺ , X ⁺ Ω, YX and Y are non-key attributes

Exist X Y F ⁺ , YX, or X is the key or Y is the key attribute

Existing X Y F ⁺ , X ⁺ Ω, YX and Y are non-key attributes

There is no X Y F ⁺ , YX, or X is the key or Y is the key attribute

A set of data representations

A set of operations used to update and supplement on database systems

A set of data representation rules

A set of operations used to manipulate database systems

Data series

Data file

relationship

Database

No key attributes exist

The above relationship has a standard form 2NF

There are unlocked properties

{A, C}, {B, E} is the key of the above relationship

Create a new relationship, satisfying a new definition

Create a new relationship, the properties are transformed from the source relationship

Create a new relationship, attributes are source relationship attributes

Create a new relationship, the source relations sets remove duplicates

Data structure in simple 1NF relations

The data structure in 1NF relations hides information anomalies

Data structures in 1NF relations allow for additional modifications conveniently

Language describes entities and linkages of entities

The set of operations has relational structures

Set of arithmetic operations

Data representation language

Independent data

Information loss

Information security