创建 SQL 数据库。 有多个主键和外键

Question

I'm currently working through an assignment that is asking me to create a SQL database using SQL Server Express. This is what it's asking for: CREATE DATABASE USING SQL

And this is the code I have tried running;

CREATE DATABASE db_Library
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USE db_Library

CREATE TABLE tbl_library_branch 
(
    library_branch_branch_id INT PRIMARY KEY NOT NULL IDENTITY (1,1),
    library_branch_branch_name VARCHAR(50) NOT NULL,
    library_branch_address VARCHAR(50) NOT NULL
);

CREATE TABLE tbl_publisher 
(
    library_publisher_publisher_name VARCHAR(50) PRIMARY KEY NOT NULL,
    library_publisher_address VARCHAR(50) NOT NULL,
    library_publisher_phone INT NOT NULL
);

CREATE TABLE tbl_books 
(
    library_books_book_id INT PRIMARY KEY NOT NULL IDENTITY (1,1),
    library_books_title VARCHAR(50) NOT NULL,
    library_books_publisher_name VARCHAR(50) NOT NULL CONSTRAINT fk_library_books_publisher_name FOREIGN KEY REFERENCES tbl_publisher(library_publisher_publisher_name) ON UPDATE CASCADE ON DELETE CASCADE
);

CREATE TABLE tbl_book_authors 
(
    library_book_authors_book_id INT NOT NULL CONSTRAINT fk_library_book_authors_book_id FOREIGN KEY REFERENCES tbl_books(library_books_book_id) ON UPDATE CASCADE ON DELETE CASCADE,
    library_book_authors_author_name VARCHAR(50) NOT NULL
);

CREATE TABLE tbl_book_copies 
(
    library_book_copies_book_id INT NOT NULL CONSTRAINT fk_library_book_copies_book_id FOREIGN KEY REFERENCES tbl_books(library_books_title),
    library_book_copies_branch_id INT NOT NULL,
    library_book_copies_number_of_copies INT NOT NULL
);

CREATE TABLE tbl_book_loans 
(
    library_book_loans_book_id INT NOT NULL,
    library_book_loans_branch_id INT NOT NULL,
    library_book_loans_card_no INT NOT NULL,
    library_book_loans_date_out INT NOT NULL,
    library_book_loans_date_due INT NOT NULL
);

CREATE TABLE tbl_borrower 
(
    library_borrower_card_no INT PRIMARY KEY NOT NULL IDENTITY (1,1),
    library_borrower_name VARCHAR(50) NOT NULL,
    library_borrower_address VARCHAR(50) NOT NULL,
    library_borrower_phone VARCHAR(50) NOT NULL
);

Using the library "Books" as an example it looks like I need to have BoodID as a primary key and Title as a primary key, but you can't have more than one primary key per table..

Then I have to take BookID from the Book_Copies table and the Book_Loans table connect to the primary key of Title in Books?

I'm beyond stuck at this point and would appreciate any resources you think could help.

Answer 1

There is no need to be so verbose. I think you want something more like this (for two tables):

CREATE TABLE tbl_publisher (
    publisher_id int IDENTITY(1, 1) PRIMARY KEY,
    publisher_name VARCHAR(50) NOT NULL UNIQUE,
    address VARCHAR(50) NOT NULL,
    phone INT NOT NULL
);

CREATE TABLE books (
    book_id INT IDENTITY (1,1) PRIMARY KEY,
    title VARCHAR(50) NOT NULL UNIQUE,
    publisher_id INT NOT NULL CONSTRAINT fk_books_publisher__id FOREIGN KEY REFERENCES tbl_publisher(publisher_id) ON UPDATE CASCADE ON DELETE CASCADE
);

Notes:

• Stick with synthetic primary keys for all the tables. That is, identity columns.
• Other columns can be declared to be unique . That is fine.
• I type quite fast. And yet I would quickly wary of typing library_book_ over and over. Such repetition just makes it harder to write and read queries.