Database test - Part 2

Expressions

Relationships

Properties

Value sets

Modify the value of some properties.

Modify the description of attributes.

Modify the value of a relationship or a group of relationships

Modify the value of a set or a set of sets.

SELECT, FROM, WHERE, GROUP BY HAVING, ORDER BY

SELECT, FROM, GROUP BY HAVING, ORDER BY

SELECT, FROM, GROUP BY HAVING, ORDER BY

SELECT, FROM, GROUP BY HAVING, WHERE, ORDER BY

Relational algebraic operations

Arithmetic operations and comparisons

Algebra expression

Comparisons.

SELECT

FROM

WHERE

GROUP BY

GROUP BY HAVING

WHERE

SELECT

FROM

Specified by the application program

Specified by a part of the database management system.

Specified in a data language

Specified in a language, part of the database management system.

They represent the same mapping.

The same relationships in expressions.

The results are the same

Relationships in defined domain expressions

Information protection on transmission lines

Allow remote, controlled access

Allow remote access

Do not allow remote access

GRANT ON TO

GRANT ON TO

GRANT ON TO

GRANT READ ON R

Data inconsistencies in storage make data lose integrity

Data integrity ensures data is always correct

Data consistency ensures easy updates and additions

Hosted organization according to database theory, repeatable attributes

Data is represented, describing many different ways.

Users working on databases can alter the data storage structure and database access strategy.

Storage structure and the above application program systems are independent of each other.

The goal of database systems is: the immutability of application systems for changes in storage structure and data access strategy.

Data normalization is the process of separating relations without losing information.

The root relationship is contained in the natural connection of projection relations.

Data stored in the database reflects data integrity.

Data normalization is the process of performing storage operations

Separation of relationships is the implementation of query and search optimization.

Relationship separation is intended to ensure data independence.

Relational separation is the optimal storage performance, memory saving.

Relationship separation is mitigating calculations.

When performing separation, the original relation is not lost.

When performing separation, the original relationship is lost.

When performing separation, the root relationship is always lost.

When performing separation, the root relationship can be lost.