myDBMS

New features

• 将bash的界面做了调整，支持连续读入sql语句
• 添加了double类型，支持对double类型的比较，插入，修改
• 将两表链接查询扩展至多表链接查询
• 添加了批处理文件runsql.sh

for run :

RE:
WSL:

• Distributor ID: Ubuntu
• Description: Ubuntu 22.04.1 LTS
• Release: 22.04
• Codename: jammy

command:
cd MYDBMS
./runsql.sh

for test :

//测试CREATE DATABASE SHOW DATABASES DROP DATABASE USE DATABASE
CREATE DATABASE XJGL;
CREATE DATABASE JUST_FOR_TEST;
CREATE DATABASE JUST_FOR_TEST;
SHOW DATABASES;
DROP DATABASE JUST_FOR_TEST;
SHOW DATABASES;
USE XJGL;

//测试CREATE TABLE SHOW TABLES DROP TABLE
CREATE TABLE STUDENT(SNAME CHAR(20),SAGE INT,SSEX INT);
CREATE TABLE COURSE(CNAME CHAR(20),CID INT);
CREATE TABLE CS(SNAME CHAR(20),CID INT,GRADE DOUBLE);
CREATE TABLE TESTTABLE(COL1 CHAR(22),COL2 INT,COL3 CHAR(22));
CREATE TABLE TEST_TABLE(COL1 CHAR(22),COL2 INT,COL3 CHAR(22));
SHOW TABLES;
DROP TABLE TEST_TABLE;
SHOW TABLES;

//测试INSERT INTO VALUES
INSERT INTO STUDENT(SNAME,SAGE,SSEX) VALUES ('ZHANGSAN',22,1);
INSERT INTO STUDENT VALUES ('LISI',23,0);
INSERT INTO STUDENT(SNAME,SAGE) VALUES ('WANGWU',21);
INSERT INTO STUDENT VALUES ('ZHAOLIU',22,1);
INSERT INTO STUDENT VALUES ('XIAOBAI',23,0);
INSERT INTO STUDENT VALUES ('XIAOHEI',19,0);
INSERT INTO CS VALUES ('LISI',1,89.9); INSERT INTO COURSE(CNAME,CID) VALUES ('DB',1);
INSERT INTO COURSE (CNAME,CID) VALUES('COMPILER',2);
insert into course (CNAME,CID) VALUES('C',3);
insert into COURSE (CNAME,CID) VALUES('C',3);

//测试单表查询
SELECT * FROM COURSE;
SELECT * FROM STUDENT;
SELECT SNAME,SAGE,SSEX FROM STUDENT;
SELECT SNAME,SAGE FROM STUDENT;
SELECT SNAME,SAGE FROM STUDENT WHERE SAGE=22;
SELECT SNAME,SAGE FROM STUDENT WHERE (((SAGE=21)));
SELECT SNAME,SAGE FROM STUDENT WHERE SAGE>21 AND SSEX=0;
SELECT SNAME,SAGE FROM STUDENT WHERE SAGE>21 OR SSEX=0;
SELECT SNAME,SAGE FROM STUDENT WHERE SAGE>21 OR SSEX=0 AND SNAME = 'LISI';
SELECT SNAME,SAGE FROM STUDENT WHERE (SAGE>21 OR SSEX=0) AND SNAME = 'LISI';
SELECT * FROM STUDENT WHERE SSEX!=1;

// 测试多表查询
SELECT * FROM STUDENT;
SELECT * FROM COURSE;
select * from student,course;
SELECT * FROM STUDENT,COURSE WHERE (SSEX=0) AND (CID=1);

//测试DELETE语句
SELECT * FROM STUDENT;
DELETE FROM STUDENT WHERE (SAGE>21) AND (SSEX=0);
SELECT * FROM STUDENT;

//测试UPDATE
SELECT * FROM STUDENT;
UPDATE STUDENT SET SAGE=21 WHERE SSEX=1;
SELECT * FROM STUDENT;
UPDATE STUDENT SET SAGE=27,SSEX=1 WHERE SNAME='ZHANGSAN';
SELECT * FROM STUDENT;

//再次测试DROP
SHOW TABLES;
DROP TABLE STUDENT;
SHOW TABLES;
DROP TABLE CS;
SHOW TABLES;
DROP TABLE TESTTABLE;
SHOW TABLES;
SHOW DATABASES;
DROP DATABASE XJGL;
SHOW DATABASES;

//正常退出
EXIT;

//多表链接查询（超过两个表）

CREATE DATABASE XJGL; CREATE TABLE STUDENT(SNAME CHAR(20),SAGE INT,SSEX INT);
CREATE TABLE COURSE(CNAME CHAR(20),CID INT);
CREATE TABLE CS(SNAME CHAR(20),CID INT,GRADE DOUBLE);
INSERT INTO STUDENT VALUES ('LISI',23,0);
INSERT INTO COURSE(CNAME,CID) VALUES ('DB',1);
INSERT INTO CS VALUES ('LISI',1,89.9); SELECT * FROM CS; SELECT * FROM COURSE;
SELECT * FROM STUDENT;
SELECT * FROM STUDENT,CS,COURSE WHERE (SSEX=0) AND (CID=1); SELECT * FROM STUDENT,CS WHERE (SSEX=0) AND (CID=1);

//测试浮点数

CREATE DATABASE XJGL; CREATE TABLE CS(SNAME CHAR(20),CID INT,GRADE DOUBLE); INSERT INTO CS VALUES ('LISI',1,89.9); SELECT * FROM CS;

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