C#数据库查询和操作大全

一：C#数据库查询之数据库连接代码：

1. SqlConnectionobjSqlConnection=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
2. objSqlConnection.Open();

二：数据库的添加记录代码：

1. inti=0;
2. strings1="",s2="";
3. i=Convert.ToInt16(textBox1.Text);
4. s1=textBox2.Text;
5. s2=textBox3.Text;
6. SqlConnectionobjSqlConnection=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
7. objSqlConnection.Open();
8. MessageBox.Show("数据库连接成功","好");
9. try
10. {
11. SqlCommandsqlcom=newSqlCommand("insertintoinfo(id,name,sex)values("+i+",‘"+s1+"‘,‘"+s2+"‘)",objSqlConnection);
12. sqlcom.ExecuteNonQuery();
13. MessageBox.Show("添加成功！","啊");
14. }
15. catch(Exceptiona)
16. {
17. MessageBox.Show(a.ToString());
18. }
19. MessageBox.Show("添加成功！","啊");
20. }

三：数据库的修改代码：

1. inti=0;
2. strings1="",s2="";
3. s1=textBox2.Text;
4. s2=textBox3.Text;
5. if(textBox1.Text.Length==0)
6. i=0;
7. else
8. i=Convert.ToInt32(textBox1.Text);
9. SqlConnectionobjSqlConnection=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
10. objSqlConnection.Open();
11. MessageBox.Show("数据库连接成功","好");
12. try
13. {
14. SqlCommandsqlcom=newSqlCommand("updateinfosetname=‘"+s1+"‘,sex=‘"+s2+"‘"+"whereid="+i,objSqlConnection);
15. sqlcom.ExecuteNonQuery();
16. MessageBox.Show("修改成功！","啊");
17. objSqlConnection.Close();
18. }
19. catch(Exceptiona)
20. {
21. MessageBox.Show(a.ToString());
22. }

四：数据库的删除代码：

1. inti=0;
2. strings1="",s2="";
3. s1=textBox2.Text;
4. s2=textBox3.Text;
5. if(textBox1.Text.Length==0)
6. i=0;
7. else
8. i=Convert.ToInt16(textBox1.Text);
9. SqlConnectionobjSqlConnection=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
10. objSqlConnection.Open();
11. MessageBox.Show("数据库连接成功","好");
12. try
13. {
14. SqlCommandsqlcom=newSqlCommand("deletefrominfowhereid="+i,objSqlConnection);
15. sqlcom.ExecuteNonQuery();
16. MessageBox.Show("删除成功！","啊");
17. objSqlConnection.Close();
18. }
19. catch(Exceptiona)
20. {
21. MessageBox.Show(a.ToString());
22. }

五：数据库的查询代码：

1.类开始：

1. DataTabledt1=newDataTable();
2. SqlDataAdapterda1=newSqlDataAdapter();

2.按钮代码：

1. inti=0,n=0;
2. strings1="",s2="";
3. s1=textBox2.Text;
4. s2=textBox3.Text;
5. if(textBox1.Text.Length==0)
6. i=0;
7. else
8. i=Convert.ToInt32(textBox1.Text);
9. SqlConnectionobjSqlConnection=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
10. objSqlConnection.Open();
11. MessageBox.Show("数据库连接成功","好");
12. stringquery="SELECT*frominfowhereid="+i;
13. DataSetobjDataSet=newDataSet();
14. SqlDataAdapterobj=newSqlDataAdapter();
15. obj.SelectCommand=newSqlCommand(query,objSqlConnection);
16. obj.Fill(objDataSet,"info");
17. SqlCommandobjSqlCommand=newSqlCommand(query,objSqlConnection);
18. SqlDataReaderobjSqlReader=objSqlCommand.ExecuteReader();
19. while(objSqlReader.Read())
20. {
21. n+=1;
22. MessageBox.Show("编号:"+objSqlReader.Getvalue(0)+"姓名:"+objSqlReader.Getvalue(1)+"性别"+objSqlReader.Getvalue(2));
23. }
24. if(n==0)
25. MessageBox.Show("数据库中没有这样的记录！");

六：C#数据库查询代码：

1. inti=0;
2. //intn=0;
3. strings1="",s2="";
4. stringsql;
5. s1=textBox2.Text;
6. s2=textBox3.Text;
7. if(textBox1.Text.Length==0)
8. {
9. i=0;
10. }
11. else
12. i=Convert.ToInt32(textBox1.Text);
13. SqlConnectionobjSqlConnection=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
14. objSqlConnection.Open();
15. MessageBox.Show("数据库连接成功","好");
16. stringquery="SELECT*frominfowhereid="+i;
17. if(i==0)
18. sql="select*frominfo";
19. else
20. sql="select*frominfowhereid="+i;
21. da1=newSqlDataAdapter(sql,objSqlConnection);
22. dt1.Clear();
23. da1.Fill(dt1);
24. dataGridView1.DataSource=dt1;

C#数据库查询之数据库的封装类代码：

1. classDBClass
2. {
3. publicvoiddbclass(stringsql)
4. {
5. try
6. {
7. SqlConnectionsqlcon=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
8. sqlcon.Open();
9. SqlTransactionobjt=sqlcon.BeginTransaction();//事物开始
10. SqlCommandsqlcom=newSqlCommand(sql,sqlcon);
11. sqlcom.Transaction=objt;//将Command对象设置为事物处理的对象
12. sqlcom.ExecuteNonQuery();
13. objt.Commit();//提交事物
14. sqlcon.Close();
15. }
16. catch(Exceptiona)
17. {
18. MessageBox.Show(a.ToString());
19. }
20. }
21. }
22. --db2数据库连接代码：
23. stringstrcon="Provider=IBMDADB2;DataSource=hfzd;UserId=db2admin;Password=db2admin";
24. //stringsql="select*fromADMINISTRATOR.HFZD";
25. stringsql="deletefromADMINISTRATOR.HFZDwhereID=1";
26. OleDbConnectionolecon=newOleDbConnection(strcon);
27. olecon.Open();
28. MessageBox.Show("数据库已连接上");
29. dt.Clear();
30. da=newOleDbDataAdapter(sql,olecon);
31. da.Fill(dt);
32. dataGridView1.DataSource=dt;
33. olecon.Close();