3. Learn the command line management code

3. Learn the command line management code
The Great sailing age 1: Creation of the world

--------------table Operation: The World of Thieves king
CREATE DATABASE One_Piece
DROP DATABASE One_Piece

CREATE TABLE ROLE (
ID INT IDENTITY (+),
NAME VARCHAR (20),
Age INT,
Reward INT
)

CREATE TABLE Area (
ID INT IDENTITY (+),
NAME VARCHAR (20),
REMARK TEXT,
)
Sp_rename ' AREA1 ', ' area '
DROP TABLE Area

INSERT into ROLE (NAME, age, reward) VALUES (' Lu.fei ', 20, 5);
SELECT * from ROLE;
Delete from ROLE;

ALTER TABLE ROLE DROP COLUMN area_id;
ALTER TABLE ROLE ADD area_id INT;
ALTER TABLE ROLE MODIFY area_id BIGINT;

-----------2.SQL Constraint
/*
1.NOT NULL
2.UNIQUE
3.PRIMARY KEY: UNIQUE constraint with auto-defined
4.FOREIGN key: In one table FOREIGN key points to PRIMARY key in another table. The
5.CHECK CHECK constraint is used to limit the range of values in a column.
6.DEFAULT Default constraints are used to insert defaults into columns
*/
1.ALTER TABLE role MODIFY NAME not NULL
2.ALTER TABLE role ADD UNIQUE (NAME )
ALTER TABLE role ADD CONSTRAINT Uc_person UNIQUE (NAME, age)
ALTER table role DROP CONSTRAINT Uc_person
3.A Lter table role Add PRIMARY key (ID)
Alter TABLE role add CONSTRAINT Pk_person PRIMARY KEY (ID, NAME)
Alter TAB LE role DROP CONSTRAINT pk_person

4.ALTER TABLE ROLE ADD FOREIGN KEY (area_id) REFERENCES area (ID)
ALTER tabl E ROLE ADD CONSTRAINT fk_perorders FOREIGN KEY (area_id) REFERENCES area (ID)
ALTER TABLE ROLE DROP CONSTRAINT fk_peror DERs

5.ALTER TABLE ROLE ADD CHECK (age<30)
ALTER TABLE ROLE ADD CONSTRAINT chk_person CHECK (age<30 and NAME is not NULL)
ALTER TABLE ROLE DROP CONSTRAINT Chk_person
INSERT into ROLE (age, NAME) VALUES (5, ' Yai si ')

--6
Alter TABLE ROLE ALTER COLUMN reward SET DEFAULT ' not find '
Alter TABLE ROLE ALTER COLUMN reward DROP DEFAULT
------------3. Index

3. Learn the command line management code