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();