1、c# 数据库连接和操作大全一：数据库连接代码：SqlConnection objSqlConnection = new SqlConnection (“server = 127.0.0.1;uid = sa; pwd =;database =test“);objSqlConnection.Open();二：数据库的添加记录代码：int i = 0;string s1 = “, s2 = “;i = Convert.ToInt16(textBox1.Text);s1 = textBox2.Text;s2 = textBox3.Text;SqlConnection objSqlConnection
2、 = new SqlConnection(“server = 127.0.0.1;uid = sa; pwd =;database =test“);objSqlConnection.Open();MessageBox.Show(“数据库连接成功“, “好“);trySqlCommand sqlcom = new SqlCommand(“insert into info(id,name,sex) values( “ + i + “,“ + s1 + “,“ + s2 + “)“, objSqlConnection);sqlcom.ExecuteNonQuery();MessageBox.Show
3、(“添加成功！“, “啊“);catch (Exception a)MessageBox.Show(a.ToString();MessageBox.Show(“添加成功！“, “啊“);三：数据库的修改代码：int i = 0;string s1 = “, s2 = “;s1 = textBox2.Text;s2 = textBox3.Text;if (textBox1.Text.Length = 0)i = 0;elsei = Convert.ToInt32(textBox1.Text);SqlConnection objSqlConnection = new SqlConnection(“
4、server = 127.0.0.1;uid = sa; pwd =;database =test“);objSqlConnection.Open();MessageBox.Show(“数据库连接成功“, “好“);trySqlCommand sqlcom = new SqlCommand(“update info set name=“+s1+“,sex=“+s2+“+“where id=“ + i, objSqlConnection);sqlcom.ExecuteNonQuery();MessageBox.Show(“修改成功！“, “啊“);objSqlConnection.Close()
5、;catch (Exception a)MessageBox.Show(a.ToString();四：数据库的删除代码：int i = 0;string s1 = “, s2 = “;s1 = textBox2.Text;s2 = textBox3.Text;if(textBox1.Text.Length=0)i=0;elsei = Convert.ToInt16(textBox1.Text);SqlConnection objSqlConnection = new SqlConnection(“server = 127.0.0.1;uid = sa; pwd =;database =test
6、“); objSqlConnection.Open();MessageBox.Show(“数据库连接成功“, “好“);trySqlCommand sqlcom = new SqlCommand(“delete from info where id=“+i, objSqlConnection);sqlcom.ExecuteNonQuery();MessageBox.Show(“删除成功！“, “啊“);objSqlConnection.Close();catch (Exception a)MessageBox.Show(a.ToString();五：数据库的查询代码：1.类开始：DataTab
7、le dt1 = new DataTable();SqlDataAdapter da1 = new SqlDataAdapter();2.按钮代码：int i = 0,n=0;string s1 = “, s2 = “;s1 = textBox2.Text;s2 = textBox3.Text;if (textBox1.Text.Length = 0)i = 0;elsei = Convert.ToInt32(textBox1.Text);SqlConnection objSqlConnection = new SqlConnection(“server = 127.0.0.1;uid = s
8、a; pwd =;database =test“);objSqlConnection.Open();MessageBox.Show(“数据库连接成功“, “好“);string query = “SELECT * from info where id=“+i;DataSet objDataSet = new DataSet();SqlDataAdapter obj = new SqlDataAdapter(); obj.SelectCommand = new SqlCommand(query, objSqlConnection);obj.Fill(objDataSet, “info“); Sq
9、lCommand objSqlCommand = new SqlCommand(query, objSqlConnection);SqlDataReader objSqlReader = objSqlCommand.ExecuteReader();while (objSqlReader.Read()n += 1;MessageBox.Show(“编号: “ + objSqlReader.Getvalue(0) + “ 姓名:“ + objSqlReader.Getvalue(1) + “ 性别“ + objSqlReader.Getvalue(2);if (n = 0)MessageBox.S
10、how(“数据库中没有这样的记录！“);六：数据库的查询代码：int i = 0;/ int n = 0;string s1 = “, s2 = “;string sql;s1 = textBox2.Text;s2 = textBox3.Text;if (textBox1.Text.Length = 0)i = 0;elsei = Convert.ToInt32(textBox1.Text);SqlConnection objSqlConnection = new SqlConnection(“server = 127.0.0.1;uid = sa; pwd =;database =test“
11、); objSqlConnection.Open();MessageBox.Show(“数据库连接成功“, “好“);string query = “SELECT * from info where id=“+i;if(i=0)sql = “select * from info “;elsesql = “select * from info where id=“ + i;da1 = new SqlDataAdapter(sql, objSqlConnection);dt1.Clear();da1.Fill(dt1);dataGridView1.DataSource = dt1;数据库的封装类代
12、码：class DBClasspublic void dbclass(string sql)trySqlConnection sqlcon = new SqlConnection(“server = 127.0.0.1;uid = sa; pwd =;database =test“);sqlcon.Open();SqlTransaction objt = sqlcon.BeginTransaction(); /事物开始SqlCommand sqlcom = new SqlCommand(sql, sqlcon);sqlcom.Transaction = objt; /将 Command 对象设
13、置为事物处理的对象sqlcom.ExecuteNonQuery();objt.Commit(); /提交事物sqlcon.Close();catch (Exception a)MessageBox.Show(a.ToString();-db2 数据库连接代码：string strcon = “Provider = IBMDADB2; Data Source=hfzd;User Id=db2admin;Password=db2admin“;/string sql = “select * from ADMINISTRATOR.HFZD“;string sql = “delete from ADMINISTRATOR.HFZD where ID=1“;OleDbConnection olecon = new OleDbConnection(strcon);olecon.Open();MessageBox.Show(“数据库已连接上“);dt.Clear();da = new OleDbDataAdapter(sql, olecon);da.Fill(dt);dataGridView1.DataSource = dt;olecon.Close();
