beginner sql missing keyword and invalid identifier - sql

Question

CREATE table Book
(
book_title varchar (100) not null ,
book_genre char(60) not null,
Date_of_publish date not null,
user_code char(7) not null ,
book_id char (7) primary key not null ,
constraint writer__id_fk foreign key (writer_id),
constraint publisher__id_fk foreign key (publisher_id)
);
I'm getting
[ORA-00905: missing keyword]
in publisher table
CREATE table publisher
(
publisher_id char (7) primary key not null,
publisher_name char(20) not null,
publisher_number char(10) not null,
publisher_email varchar2(60) not null,
publisher_address varchar2(60) not null,
);
I'm getting
[ORA-00904: : invalid identifier]

Answer 1

The following SQL creates a FOREIGN KEY on the "PersonID" column when the "Orders" table is created:
CREATE TABLE Orders (
OrderID int NOT NULL,
OrderNumber int NOT NULL,
PersonID int,
PRIMARY KEY (OrderID),
FOREIGN KEY (PersonID) REFERENCES Persons(PersonID)
);
Refer this link for more details
https://www.w3schools.com/sql/sql_foreignkey.asp
Hope this helps.

Answer 2

Welcome to the wonderful world of SQL! :-)
General remark:
Please tell us what kind of DBMS you're using. MySQL? SQL Server? Oracle? SQlite? Different systems use different kinds of syntaxes.
First statement:
The problem seems to be in the FOREIGN KEY-portion.
Usually, you'll state something like:
CONSTRAINT [constraint_name] FOREIGN KEY([column_in_this_table]) REFERENCES OTHER_TABLE([column_in_other_table])
edit (added):
The [column_in_this_table] has to exist in your DDL (CREATE TABLE-statement), like so:
CREATE TABLE Book ( book_title ... etc., publisher_id INT, CONSTRAINT FK_publ_id FOREIGN KEY(publisher_id) REFERENCES publisher(publisher_id));
Here, you'll have a 'original' column called 'publisher_id', in the 'publisher'-table. You refer to it from within the 'Book'-table, by first having a 'publisher_id' column in the 'Book'-table (which should have the same DDL as the original column by the way). Next, you'll add a FOREIGN KEY to the 'Book'-table, that is imposed on the Book(publisher_id) column. Note, that you could also name the column in your 'Book'-table differently -- like, say, 'Spongebob' or 'Patrick'. But for future use, you'd like naming conventions that tell what you might expect to find in a column. So you'd name columns for what they contain.
Second statement:
The problem is with the last portion of your statement, where there's a comma after the NOT NULL portion for column publisher_address.
(Part of) your statement:
publisher_address varchar2(60) not null, );
Try replacing that with:
publisher_address VARCHAR2(60) NOT NULL);
edit (note to self):
VARCHAR2 turns out to be a valid datatype in Oracle databases (see:
Oracle documentation)

Answer 3

For your first table, the Foreign Keys do not reference any table. For your second table, I would imagine that comma after your last column isn't helping anything.

Answer 4

So this is the answer.
CREATE table Book
(
book_title varchar (100) not null ,
book_genre char(60) not null,
Date_of_publish date not null,
user_code char(7) not null ,
publisher_id char (7) not null,
writer_id char(7) not null,
book_id char (7) primary key not null ,
CONSTRAINT book_writer_id_fk FOREIGN KEY(writer_id) REFERENCES writer(writer_id),
CONSTRAINT book_publisher_id_fk FOREIGN KEY(publisher_id) REFERENCES publisher(publisher_id)
);
CREATE table publisher
(
publisher_id char (7) primary key not null,
publisher_name char(20) not null,
publisher_number char(10) not null,
publisher_email varchar2(60) not null,
publisher_address varchar2(60) not null
);