databases question and need the explanation and answer to help me learn.
please answer well
Requirements: please answer well
In a train stations database, an employee MUST be a train driver, ticket issuer or train attendant, with following constraint: Same employee cannot occupy more than one job type.
Draw EER diagram to represent specialization of employees in the train station database.
Draw the schema mapping (logical database design) for the following part of ER diagram for train station database. When appropriate use the foreign key option.
Suppose you are creating a database for a library management system. Explain how you would create a table for the “books” entity and insert some sample data, and then alter the table to add a new column for the “authorID” attribute and update “authorID” with some data. Finally, write a SQL query to retrieve all the books that were published after the year 2000.
Note that this book schema has several columns, including “book_id” as the primary key, “title”, “authorN”, “publisher”, “publication_year”, “isbn”, “language”, and “num_pages”. It also includes “available” column that is set to “true” by default and can be used to track the availability of the book.
Write a SQL query that retrieves the names and email addresses of all students who are enrolled in at least one course in the “Computer Science” department and have a graduation year of 2022 or later. Include the course name and instructor name for each enrollment in the output. Schemas of the tables are below.
student_id: unique identifier for the student
name: name of the student
email: email address of the student
major: field of study for the student
graduation_year: expected year of graduation for the student
course_id: unique identifier for the course
course_name: name of the course
instructor_name: name of the instructor teaching the course.
department: department offering the course.
course_description: description of the course
enrollment_id: unique identifier for the enrollment
student_id: identifier for the student enrolled in the course.
course_id: identifier for the course the student is enrolled in
enrollment_date: date the student enrolled in the course
grade: grade the student received in the course
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