Tianchi Dragon Ball Project-SQL Training Camp-task01 Check-in

Practice questions:

1. Write a CREATE TABLE statement to create a table Addressbook (address book) that contains the items listed in Table 1-A, and set primary key constraints for the regist_no (registration number) column

CREATE TABLE Addressbook (
		regist_no int not null,
		a_name varchar(128) not null,
		address varchar(256) not null,
		tel_no varchar(10),
		mail_address char(20),
		PRIMARY KEY(regist_no));
		

2. Suppose you forgot to add the following column postal_code (postal code) when creating the Addressbook table in Exercise 1.1, please add this column to the Addressbook table.

Column name: postal_code

Data type: fixed-length string type (length is 8)

Constraint: cannot be NULL

ALTER TABLE Addressbook add (postal_code char(10) not null);

3. Write a SQL statement to delete the Addressbook table.

DROP TABLE Addressbook;

4. Write SQL statements to restore the deleted Addressbook table.

START TRANSACTION;
DROP TABLE Addressbook;
ROLLBACK;