C#__数据库连接和操作大全+经典SQL语句大全

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c# 数据库连接和操作大全.txt wxh zt

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 = "";

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)

{

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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("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 = "";

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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)

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");

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string query = "SELECT * from info where id="+i;

SqlCommand objSqlCommand = new SqlCommand(query,

objSqlConnection);

SqlDataReader objSqlReader = objSqlCommand.ExecuteReader();

while (objSqlReader.Read())

{

n += 1;

MessageBox.Show("编号: " + objSqlReader.Getvalue(0) + " 姓名:" +

}

if (n == 0)

MessageBox.Show("数据库中溡有这样的记录！");

s2 = textBox3.Text;

if (textBox1.Text.Length == 0)

{

i = 0;

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else

i = Convert.ToInt32(textBox1.Text);

= sa; pwd =;database =test");

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.Fill(dt1);

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