C#数据库连接操作大全

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 = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test");

            objSqlConnection.Open();

            

            MessageBox.Show("数据库连接成功", "好");

try

               {

                  SqlCommand sqlcom = new SqlCommand("insert into info(id,name,sex) values( " + i + ",'" + s1 + "','" + s2 + "')", objSqlConnection);

                  sqlcom.ExecuteNonQuery();

                   MessageBox.Show("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;

            else

                i = Convert.ToInt32(textBox1.Text);

SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test");

            objSqlConnection.Open();

            MessageBox.Show("数据库连接成功", "好");

            try

            {

                SqlCommand 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();

            }

            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;

            else

                 i = Convert.ToInt16(textBox1.Text);

            SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test");            

            objSqlConnection.Open();

            MessageBox.Show("数据库连接成功", "好");

            try

            {

                SqlCommand 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：

                  DataTable 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;

            else

                i = Convert.ToInt32(textBox1.Text);

            SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; 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");

SqlCommand 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.Show("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;

                

            }

            else

                i = Convert.ToInt32(textBox1.Text);

           SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test");          

            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 ";

            else

                  sql = "select * from info where id=" + i;

da1 = new SqlDataAdapter(sql, objSqlConnection);

dt1.Clear();

            da1.Fill(dt1);

            dataGridView1.DataSource = dt1;

数据库的封装类代码：

class DBClass

    {

public void dbclass(string  sql)

        {

            try

            {

                SqlConnection 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();