Videotutorial 5: Fundamentos de Bases de Datos

Videotutorial 5: Database Fundamentals

• This videotutorial covers database normalization.
• The tutorial includes a complete exercise, Entity-Relationship (E-R) Model, Relational Model, and key normalization concepts.
• A summary of general concepts is also provided.

Exercise 1: Putting Theory into Practice

• The exercise involves creating an entity-relationship diagram and converting it into a relational model, following the first normal form.
• The exercise describes a database for a course with students and assignments (PACs).
• Each student has a unique ID, name, age, and languages spoken.
• Each PAC has a unique ID, number of questions, opening and closing dates, the number of days it is open, and the maximum score.
• Each question in a PAC is worth 0.2 points. This allows calculating the maximum score for each PAC.

Exercise 1 Diagram

• Shows the relationship between ALUMNO, HACER, and PAC tables.
• The tables include attributes like id_alu, edad, Nombre, nota, tiempo, id_pac, fecha_aper, dias_apertura, fecha_cierre, número_preg, and puntuación_max.

ER & Normalized Diagram to 3NF

• The exercise showcases the normalization of tables to the third normal form (3NF).
• Shows the structure of the ALUMNO, PAC, ALUMNO_PAC, and IDIOMAS_ALUMNOS tables.
• The ALUMNO table contains unique student identifiers.
• The PAC table includes data related to assignments.
• The ALUMNO_PAC table links students and assignments with attributes like the student's score and time spent on each assignment (PAC).
• The IDIOMAS_ALUMNOS table manages the languages a student knows.

Exercise 2: Normalizing a Table

• This exercise focuses on normalizing the ALQUILERES table.
• The ALQUILERES table data is explained, including FechaDeAlquiler (PK), CódigoLibroAlquilado (PK), and CódigoUsuario (PK)
• The table includes multiple attributes like book title, editorial names, and user attributes.
• The tutorial highlights that a user can rent the same book multiple times.
• Updating user phone numbers and editorial locations proves problematic due to the data structure in the ALQUILERES table.

Normalization Solution (3NF)

• The solution shows the breakdown of the ALQUILERES table into multiple, interconnected tables.
• This breakdown is done to improve data integrity and efficiency.
• The process of normalization is described.
• As a result the single original table is transformed into 6 tables that are interconnected.

Normal Forms (1NF, 2NF, 3NF)

• Explains how to eliminate multi-valued fields.
• Provides details on creating new tables to organize multi-valued attributes (e.g., TELEFONOS, AUTORES).

Normalization > 2NF

• Explains how the normalized data is further decomposed to resolve partial dependencies.
• This ensures that non-key attributes rely on the entire primary key. ALQUILERES table is further normalized.
• Relationships are described with the inclusion of new tables like LIBROS, EDITORIALES, and USUARIOS.

Normalization > 3NF

• The video clarifies how LIBROS table can be further normalized to eliminate transitive dependencies.
• This step removes redundancy in the database.
• The solution explains the creation of a new table EDITORIALES.

Summary of Normalization Process

• This section summarizes the process of converting a single table into multiple tables with better structure.
• Creating related tables to improve data accuracy and consistency is highlighted.

Contextualization

• This part of the tutorial discusses planning and developing a database, considering conceptual, logical, and physical levels.
• The different phases involved are explained, along with details about the database design, implementation choices, and efficiency.

Review Questions

• The presentation contains review questions on the concepts discussed.
• The questions include the creation of E-R diagrams for differing scenarios.
• There's a task to normalize, creating models from tables using 1NF, 2NF, and 3NF steps.

Conclusion

• Emphasizes the importance of database design considerations.
• The normalization process is demonstrated as a key concept in structuring efficient database systems.

Neste videotutorial abordarase a normalización de bases de datos. Inclúe un exercicio completo que presenta o Modelo de Entidade-Relación e o Modelo Relacional, así como os conceptos clave de normalización. Tamén se proporciona un resumo dos conceptos xenerais tratados no curso.