VB.NET怎样连接数据库
Imports System.Data
Imports System.Data.SqlClient
Module 连接数据库
Public Server1 As String
Public DataBase1 As String
Public Function GetTable(ByVal sqlstr$) As DataTable
Dim SqlConn As SqlConnection = New SqlConnection(“server=“ & Server1 & “;database=“ & DataBase1 & “;integrated security=true“) ’声明这些SQL的类
Dim facDataAdapter As SqlDataAdapter = New SqlDataAdapter
Dim SqlComm As SqlCommand = New SqlCommand(sqlstr, SqlConn)
facDataAdapter.SelectCommand = SqlComm
Dim dt As DataTable = New DataTable
facDataAdapter.Fill(dt)
Return dt
End Function
End Module
从哪里开始学习ACCESS数据库（新手）
基础很简单,无非是建表和查询,后面的窗体和模块就先不要去学了.
要真的学习,给你个方法,看书,照书上的做是基础的基础,但往往你会云里雾里.
不如看一遍书,无所谓懂与不懂,先看完.最后你做一个简单的任务,然后为了达到这个任务再去到书上找,网上找,直到你完成你的任务,然后再试着做个难点的任务,这样下去你会学习很快而且效果很好.
相信我,我说的是对的.以后你会明白的.
ACCESS 无所谓那个版本,用2003的吧,现在2007的教材不是很多.
发你一个太大,网上一搜一大堆的东西还是自己下一个吧.
MySQL习题 求数据库高手解答
create table stu1 (
Id int auto_increment primary KEY,
Name VARCHAR(20) not null ,
Sex varchar(4) ,
Brith Date ,
department VARCHAR(20)not null,
address VARCHAR(50)
)
create table score(
Id INT auto_increment PRIMARY KEY,
stu_id int,
FOREIGN KEY(stu_id) REFERENCES stu1(Id) on DELETE CASCADE,
C_name VARCHAR(20),
grade int
)
SELECT *from stu1
INSERT INTO stu1 VALUES( 901,’张老大’, ’男’,’1985-06-05’,’计算机系’, ’北京市海淀区’);
INSERT INTO stu1 VALUES( 902,’张老二’, ’男’,’1986-06-05’,’中文系’, ’北京市昌平区’);
INSERT INTO stu1 VALUES( 903,’张三’, ’女’,’1990-06-05’,’中文系’, ’湖南省永州市’);
INSERT INTO stu1 VALUES( 904,’李四’, ’男’,’1990-06-05’,’英语系’, ’辽宁省阜新市’);
INSERT INTO stu1 VALUES( 905,’王五’, ’女’,’1991-06-05’,’英语系’, ’福建省厦门市’);
INSERT INTO stu1 VALUES( 906,’王六’, ’男’,’1988-06-05’,’计算机系’, ’湖南省衡阳市’);
SELECT *from Score
INSERT INTO score(stu_id,C_name,grade) VALUES(901, ’计算机’,98);
INSERT INTO score(stu_id,C_name,grade) VALUES(901, ’英语’, 80);
INSERT INTO score(stu_id,C_name,grade) VALUES(902, ’计算机’,65);
INSERT INTO score(stu_id,C_name,grade) VALUES(902, ’中文’,88);
INSERT INTO score(stu_id,C_name,grade) VALUES(903, ’中文’,95);
INSERT INTO score(stu_id,C_name,grade) VALUES(904, ’计算机’,70);
INSERT INTO score(stu_id,C_name,grade) VALUES(904, ’英语’,92);
INSERT INTO score(stu_id,C_name,grade) VALUES(905, ’英语’,94);
INSERT INTO score(stu_id,C_name,grade) VALUES(906, ’计算机’,90);
INSERT INTO score(stu_id,C_name,grade) VALUES(906, ’英语’,85);
/*查询 student 表的第 2 条到 4 条记录*/
SELECT * from stu1 LIMIT 2,2;
/*从 student 表中查询计算机系和英语系的学生的信息*/
SELECT *from stu1 WHERE department in(’计算机系’,’英语系’);
/*从 student 表中查询年龄 18~22 岁的学生信息*/
SELECT YEAR(’1990-09-09’)
SELECT YEAR(NOW())-YEAR(’1990-09-09’);
SELECT s.Name,s.age,s.Brith from (SELECT *,YEAR(NOW())-YEAR(Brith)as age FROM stu1)as s WHERE s.age》23 and s.age《28;
/*8.从 student 表中查询每个院系有多少人*/
SELECT department,COUNT(id) from stu1 GROUP BY(department);
/*从 score 表中查询每个科目的最高分*/
(SELECT C_name,max(grade)as scote_m from Score GROUP BY C_name)as h
SELECT id,h.C_name,h.scote_m FROM score,(SELECT C_name,max(grade)as scote_m from Score GROUP BY C_name)as h
WHERE h.C_name=Score.C_name and h.scote_m=Score.grade;
/*10.查询李四的考试科目（c_name）和考试成绩（grade）*/
SELECT name,C_name,grade from stu1,score where name=’李四’and stu1.id=score.stu_id
SELECT stu_id,C_name,grade FROM score WHERE stu_id in(SELECT id FROM stu1 where name=’李四’)
/*12.计算每个学生的总成绩*/
SELECT grade_sum_t.grade_sum,grade_sum_t.stu_id,NAME,department FROM stu1,
(SELECT sum(grade)as grade_sum,stu_id from score GROUP BY stu_id )as grade_sum_t
where grade_sum_t.stu_id=stu1.id;
/*13.计算每个考试科目的平均成绩*/
SELECT C_name,AVG(grade) from score GROUP BY C_name
/*14.查询计算机成绩低于 95 的学生信息*/
SELECT * FROM stu1 WHERE id IN(SELECT stu_id from score WHERE C_name=’计算机’ AND grade《95);
/*15.查询同时参加计算机和英语考试的学生的信息*/
SELECT * FROM stu1 WHERE id IN(
SELECT stu_id FROM score WHERE C_name=’英语’ AND stu_id in(
SELECT stu_id FROM score WHERE C_name=’计算机’))
/*16.将计算机考试成绩按从高到低进行排序*/
/*18.查询姓张或者姓王的同学的姓名、院系和考试科目及成绩*/
SELECT Name,department,C_name,grade FROM stu1,score WHERE stu1.id=score.stu_id AND (Name LIKE ’王%’ OR Name LIKE ’张%’);
SELECT *from Score
/*19.查询都是湖南的学生的姓名、年龄、院系和考试科目及成绩*/
SELECT YEAR(NOW())-YEAR(Brith) FROM stu1;
SELECT Name,YEAR(NOW())-YEAR(Brith) as age,department,C_name,grade FROM stu1,score WHERE stu1.Id=score.stu_id AND address LIKE ’湖南%’ ;
/*20-*/
INSERT INTO score(stu_id,C_name,grade) VALUES(903, ’物理’,80);
INSERT INTO score(stu_id,C_name,grade) VALUES(903, ’化学’,53);
INSERT INTO score(stu_id,C_name,grade) VALUES(903, ’生物’,59);
INSERT INTO score(stu_id,C_name,grade) VALUES(904, ’物理’,55);
INSERT INTO score(stu_id,C_name,grade) VALUES(904, ’化学’,56);
INSERT INTO score(stu_id,C_name,grade) VALUES(904, ’生物’,50);
INSERT INTO score(stu_id,C_name,grade) VALUES(905, ’物理’,100);
INSERT INTO score(stu_id,C_name,grade) VALUES(905, ’化学’,90);
INSERT INTO score(stu_id,C_name,grade) VALUES(905, ’生物’,54);
SELECT stu_id,AVG(grade) FROM score WHERE stu_id IN(SELECT stu_id FROM score1 WHERE grade《60 GROUP BY stu_id HAVING COUNT(stu_id)》=2)GROUP BY stu_id
SELECT *FROM score1
-vb net 数据库
