São dadas a seguir duas tabelas no banco de dados PostgreSQL: orders e customers. CREATE TABLE customers ( customer_id SERIAL PRIMARY KEY, customer_name VARCHAR(100) ); CREATE TABLE orders ( order_id SERIAL PRIMARY KEY, order_date DATE, customer_id INT, FOREIGN KEY (customer_id) REFERENCES customers(customer_id) ); Qual alternativa altera a definição dessa chave estrangeira de modo que, quando um registro na tabela customers for deletado, a coluna customer_id na tabela orders seja atualizada para NULL? A) ALTER TABLE orders DROP CONSTRAINT orders_customer_id_fkey, ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id) REFERENCES customers(customer_id) ON DELETE RESTRICT NULL; B) ALTER TABLE orders DROP CONSTRAINT orders_customer_id_fkey, ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id) REFERENCES customers(customer_id) ON DELETE CASCADE NULL; C) ALTER TABLE orders DROP CONSTRAINT orders_customer_id_fkey, ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id) REFERENCES customers(customer_id) ON DELETE SET DEFAULT NULL; D) ALTER TABLE orders DROP CONSTRAINT orders_customer_id_fkey, ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id)REFERENCES customers(customer_id) ON DELETE SET NULL;

D) ALTER TABLE orders DROP CONSTRAINT orders_customer_id_fkey, ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id)REFERENCES customers(customer_id) ON DELETE SET NULL;

Questões Banco de Dados

São dadas a seguir duas tabelas no banco de dados PostgreSQL: orders e customers.

Responda: São dadas a seguir duas tabelas no banco de dados PostgreSQL: orders e customers. CREATE TABLE customers ( customer_id SERIAL

1Q909890 | Banco de Dados, Analista de Tecnologia da Informação, UFMT, UFMT, 2024

São dadas a seguir duas tabelas no banco de dados PostgreSQL: orders e customers.
CREATE TABLE customers ( customer_id SERIAL PRIMARY KEY, customer_name VARCHAR(100) );

CREATE TABLE orders ( order_id SERIAL PRIMARY KEY, order_date DATE, customer_id INT, FOREIGN KEY (customer_id) REFERENCES customers(customer_id) );

Qual alternativa altera a definição dessa chave estrangeira de modo que, quando um registro na tabela customers for deletado, a coluna customer_id na tabela orders seja atualizada para NULL?

✂️ a) ALTER TABLE orders DROP CONSTRAINT orders_customer_id_fkey, ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id) REFERENCES customers(customer_id) ON DELETE RESTRICT NULL;
✂️ b) ALTER TABLE orders DROP CONSTRAINT orders_customer_id_fkey, ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id) REFERENCES customers(customer_id) ON DELETE CASCADE NULL;
✂️ c) ALTER TABLE orders DROP CONSTRAINT orders_customer_id_fkey, ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id) REFERENCES customers(customer_id) ON DELETE SET DEFAULT NULL;
✂️ d) ALTER TABLE orders DROP CONSTRAINT orders_customer_id_fkey, ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id)REFERENCES customers(customer_id) ON DELETE SET NULL;