 
Drop Table IF Exists 專案供應零件;
Drop Table IF Exists 供應商;
Drop Table IF Exists 零件;
Drop Table IF Exists 專案;
Drop view IF Exists john_view;


CREATE TABLE 供應商(
  供應商代號 VARCHAR(10) ,
  供應商名稱 VARCHAR(10),
  城市 VARCHAR(10),
  PRIMARY KEY(供應商代號)
);


CREATE TABLE 零件(
  零件代號 VARCHAR(10) ,
  零件名稱 VARCHAR(10) ,
  顏色 VARCHAR(2),
  重量 DEC(5,2),
  PRIMARY KEY(零件代號)
);

CREATE TABLE 專案(
  專案代號 VARCHAR(10) ,
  專案名稱 VARCHAR(10),
  城市 VARCHAR(10),
  PRIMARY KEY(專案代號)
);


CREATE TABLE 專案供應零件(
  供應商代號 VARCHAR(10) ,
  零件代號 VARCHAR(10) ,
  專案代號 VARCHAR(10) ,
  數量 INT,
  
  PRIMARY KEY(供應商代號,零件代號,專案代號),
  
  FOREIGN KEY(供應商代號) REFERENCES  供應商(供應商代號),
  -- 	ON DELETE CASCADE ON UPDATE CASCADE,
  FOREIGN KEY(零件代號)   REFERENCES  零件(零件代號),
 --  ON DELETE CASCADE ON UPDATE CASCADE,
  FOREIGN KEY(專案代號)   REFERENCES  專案(專案代號)
 --   ON DELETE CASCADE ON UPDATE CASCADE
);
insert into 供應商 values ('S1', '大勝', '台南');
insert into 供應商 values ('S2', '冠軍', '高雄');
insert into 供應商 values ('S3', '無敵', '台中');
insert into 供應商 values ('S4', '一級棒','高雄');

insert into 零件 values ('P1', '螺絲釘','黑',14.0);
insert into 零件 values ('P2', '螺帽','黑',16.0);
insert into 零件 values ('P3', '齒輪','綠',27.0);
insert into 零件 values ('P4', '板手','藍',63.0);
insert into 零件 values ('P5', '撬子','棕',80.0);

insert into 專案 values ('J1', '火星','台中');
insert into 專案 values ('J2', '土星','高雄');
insert into 專案 values ('J3', '太陽','台中');

insert into 專案供應零件 values ('S1', 'P1','J2',300);
insert into 專案供應零件 values ('S1', 'P1','J3',100);
insert into 專案供應零件 values ('S1', 'P4','J1',500);
insert into 專案供應零件 values ('S2', 'P2','J1',400);
insert into 專案供應零件 values ('S2', 'P3','J3',600);
insert into 專案供應零件 values ('S3', 'P1','J2',300);
insert into 專案供應零件 values ('S4', 'P3','J1',200);
insert into 專案供應零件 values ('S4', 'P4','J1',700);
insert into 專案供應零件 values ('S4', 'P5','J2',100);
-- ////////////////////////////////////以上是題目table

insert into 專案供應零件 values('S1', 'P2', 'J1', 500);

insert into 供應商(供應商代號,供應商名稱) values('S5', '第一');

update 零件 set 顏色='黑' where 顏色='灰';

select * from  專案供應零件;
select * from  供應商;
select * from  零件;
select * from  專案;

DROP table 專案 CASCADE ;

select * from  專案供應零件;
select * from  供應商;
select * from  零件;

IF (OBJECT_ID(專案) IS NOT NULL )
BEGIN
  PRINT 專案
END
ELSE
BEGIN 
  PRINT 專案
END
-- IF (EXISTS (SELECT * FROM 專案));

-- update 零件 set 顏色='X色' where 顏色='黑';
-- insert into 專案供應零件(供應商代號,零件代號,專案代號,數量) values ('S1', 'P2', 'J1', 500);

created 2 years ago

PostgreSQL online editor

Write, Run & Share PostgreSQL queries online using OneCompiler's PostgreSQL online editor and compiler for free. It's one of the robust, feature-rich online editor and compiler for PostgreSQL. Getting started with the OneCompiler's PostgreSQL editor is really simple and pretty fast. The editor shows sample boilerplate code when you choose database as 'PostgreSQL' and start writing queries to learn and test online without worrying about tedious process of installation.

About PostgreSQL

PostgreSQL is a open source relational database system and is also knows as Postgres.

Key Features:

Postgres is not only free and open-source but also it is highly extensible.
Custom Data types and funtions from various programming languaues can be introduced and the good part is compiling entire database is not required.
ACID(Atomicity, Consistency, Isolation, Durability) compliant.
First DBMS which implemented Multi-version concurrency control (MVCC) feature.
It's the default database server for MacOS.
It supports all major operating systems like Linux, Windows, OpenBSD,FreeBSD etc.

Syntax help

1. CREATE

CREATE command is used to create a table, schema or an index.

Syntax:

         CREATE TABLE table_name (
                column1 datatype,
                column2 datatype,
                ....);

2. ALTER

ALTER command is used to add, modify or delete columns or constraints from the database table.

Syntax

ALTER TABLE Table_name ADD column_name datatype;

3. TRUNCATE:

TRUNCATE command is used to delete the data present in the table but this will not delete the table.

Syntax

TRUNCATE table table_name;

4. DROP

DROP command is used to delete the table along with its data.

Syntax

DROP TABLE table_name;

5. RENAME

RENAME command is used to rename the table name.

Syntax

ALTER TABLE table_name1 RENAME to new_table_name1;

6. INSERT

INSERT Statement is used to insert new records into the database table.

Syntax

INSERT INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...);

7. SELECT

Select statement is used to select data from database tables.

Syntax:

SELECT column1, column2, ...
FROM table_name;

8. UPDATE

UPDATE statement is used to modify the existing values of records present in the database table.

Syntax

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;

9. DELETE

DELETE statement is used to delete the existing records present in the database table.

Syntax

DELETE FROM table_name where condition;