SQL-2

What 1F says?

• a single cell must not hold more than one value (atomicity)
• has no partial dependency. That is, all non-key attributes are fully dependent on a primary key.
• there must be a primary key for identification
• each column must have only one value for each row in the table

How many types of relationships between tables has SQL?

• 1
• 2
• 3
• 4

What type of relationship is schools and pupils?

• one to one
• one to many
• many to many

What type of relationship is cities and tourists?

• one to one
• one to many
• many to many

What type of relationship is cars and technicalInspection?

• one to one
• one to many
• many to many

WHat type of relationship is movies and genres?

• one to one
• one to many
• many to many

How create table with foreign key?

• CREATE TABLE persons(person_id int, name varchar(30), lastname varchar(50), card_id int, FOREIGN KEY card_id REFERENCES cards(card_id);
• CREATE TABLE persons(person_id int, name varchar(30), lastname varchar(50), FOREIGN KEY (card_id) REFERENCES cards(card_id);
• CREATE TABLE persons(person_id int, name varchar(30), lastname varchar(50), card_id int, FOREIGN KEY (card_id) REFERENCES cards(card_id);
• CREATE TABLE persons(person_id int, name varchar(30), lastname varchar(50), card_id int FOREIGN KEY (card_id) REFERENCES cards;

When HAVING keyword is used in SQL?

• In conjunction with the GROUP BY clause and is applied to filter the results of a query based on aggregated values
• It is typically used when you want to filter the results of a grouped query by conditions that involve aggregate functions.
• As foreign key reference when creating a table
• Specifies a condition that the aggregated values must meet for the row to be included in the result set.

Which foreign key constraints has default behavior?

• cascade
• restrict

Common columns betweent tables:

• Can have the same or different column names
• Must have the same data type and size
• At least one of them must be primary key
• Can't have the same column names
• Must be renamed with aliases