后 delete from Course where cno = ‘当前选中行的课号’;
DialogResult result = MessageBox.Show(\是否删除此记录并删除对应成绩表相关内容?\提示!\
if (result == DialogResult.Yes) {
string Sql = \from sc where cno = '\+ this.dataGridView[0,
this.dataGridView.CurrentCellAddress.Y].Value.ToString() + \
DataAccess DA = new DataAccess(); DA.ExeSQL(Sql);
string SqlText = \
this.dataGridView[0,
this.dataGridView.CurrentCellAddress.Y].Value.ToString() + \
DA = new DataAccess(); DA.ExeSQL(SqlText);
MessageBox.Show(\删除成功!\ this.DBDataGrid(); }
if (result == DialogResult.No) {
return; }
⑤添加完新课程可以向课程中添加学生
用到的sql语句：
insert into sc(sno,cno) values ('学号','课号');//不插入成绩
单条添加：添加选中行的学生。 全部添加：添加表中全部学生。 if (this.dataGridView.Rows.Count != 0) {
string Sql = \* from sc where sno = '\+
this.dataGridView[0, this.dataGridView.CurrentCellAddress.Y].Value.ToString() + \
DataAccess DA = new DataAccess(); if (DA.IsRead(Sql) == false) {
DA = new DataAccess();
string SqlText = \+
this.dataGridView[0,
+
\
+
this.dataGridView.CurrentCellAddress.Y].Value.ToString() this.textBox_cno.Text.Trim() + \
MessageBox.Show(\添加成功!\ } else {
MessageBox.Show(\学号为\+ this.dataGridView[0, this.dataGridView.CurrentCellAddress.Y].Value.ToString() + \的学生已在该班级中\
} }
4）、成绩管理界面
（1）查询过程通过Student表和Sc表连接起来进行操作 用到的sql语句：
select student.sno as 学生编号,sname as 学生姓名,sc.cno as 课程号,cname as 课程名,grade as 成绩 from student , course , sc where student.sno=sc.sno and sc.cno=course.cno and student.sno like '学号%' and student.sname like '%姓名%'and course.cname like '%课程名\and student.sdept like'%系别%'and course.cno like '%课号%';
string SqlText = \student.sno as 学生编号,sname as 学生姓名,sc.cno as 课程号,cname as 课程名,grade as 成绩 from student , course , sc where student.sno=sc.sno and sc.cno=course.cno and student.sno like '\+ this.textBox_sno.Text.Trim() + \and student.sname like '%\+ this.textBox_sname.Text.Trim()
+
\
course.cname
like
'%\
+
this.text_cname.Text.Trim() + \and student.sdept like '%\+ this.text_dept.Text.Trim()
+
\
course.cno
like
'%\
+
this.textBox_cno.Text.Trim() + \
DataAccess DA = new DataAccess(); this.dt = DA.ExeSQLdt(SqlText);
this.dataGridView.DataSource = this.dt.DefaultView; this.cm = (CurrencyManager)BindingContext[this.dt]; dataGridView.Columns[\课程号\
dataGridView.Columns[\学生编号\ dataGridView.Columns[\学生姓名\ dataGridView.Columns[\课程名\ if (this.dataGridView.Rows.Count != 0) {
for (int i = 0; i < this.dataGridView.Rows.Count; ) {
this.dataGridView.Rows[i].DefaultCellStyle.BackColor System.Drawing.Color.Pink;
i += 2; } }
（2）删除、修改操作只对Sc表成绩或整条数据有影响 用到的sql语句：
delete from sc where sno='学号' and cno = '课号';
update sc set grade = 新成绩 where cno = '课号' and sno = '学号';
=
if (this.dataGridView.Rows.Count != 0) {
for (int i = 0; i < this.dataGridView.Rows.Count-1;i++ ) {
if (this.dataGridView[4, i].Value.ToString() != \ {
DataAccess DA = new DataAccess();
string SqlText = \sc set grade = \+ int.Parse(this.dataGridView[4, i].Value.ToString()) + \where cno = '\+ this.dataGridView[2, i].Value.ToString() + \and sno = '\+ this.dataGridView[0, i].Value.ToString() + \
DA.ExeSQL(SqlText); } else {
DataAccess DA = new DataAccess();