Relational databases：練習問題

Which SQL keyword is used to add a new record to a table named Products?

Which SQL command would be used to change the Price of all items in the Stock table where the CategoryID is 5?

A database designer discovers that a table has a transitive dependency, where a non-key attribute is dependent on another non-key attribute.

What must be done to bring this table into Third Normal Form (3NF)?

Which of the following defines a foreign key in a relational database?

When two different users attempt to update the same record in a client-server database simultaneously, a problem known as a 'lost update' can occur.

Which mechanism is most commonly used to prevent this by ensuring only one user can edit a record at a time?

Define the term composite primary key.

A database designer uses a foreign key. What is the specific purpose of this attribute in terms of relational integrity?

In a relational database, what is the term for a single row within a table?

Define the term Composite Primary Key and provide a specific example of a table structure where a composite primary key would be necessary.

Explain the concept of a Foreign Key in a relational database and describe its primary purpose in maintaining data integrity.