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：

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

二：数据库的添加记录代码：

inti=0;
strings1="",s2="";
i=Convert.ToInt16(textBox1.Text);
s1=textBox2.Text;
s2=textBox3.Text;

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

MessageBox.Show("数据库连接成功","好");

try
{
SqlCommandsqlcom=newSqlCommand("insertintoinfo(id,name,sex)values("+i+",'"+s1+"','"+s2+"')",objSqlConnection);
sqlcom.ExecuteNonQuery();
MessageBox.Show("添加成功！","啊");
}
catch(Exceptiona)
{
MessageBox.Show(a.ToString());
}
MessageBox.Show("添加成功！","啊");
}

三：数据库的修改代码：

inti=0;
strings1="",s2="";
s1=textBox2.Text;
s2=textBox3.Text;
if(textBox1.Text.Length==0)
i=0;
else
i=Convert.ToInt32(textBox1.Text);

SqlConnectionobjSqlConnection=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
objSqlConnection.Open();
MessageBox.Show("数据库连接成功","好");
try
{
SqlCommandsqlcom=newSqlCommand("updateinfosetname='"+s1+"',sex='"+s2+"'"+"whereid="+i,objSqlConnection);
sqlcom.ExecuteNonQuery();
MessageBox.Show("修改成功！","啊");
objSqlConnection.Close();
}
catch(Exceptiona)
{
MessageBox.Show(a.ToString());
}

四：数据库的删除代码：

inti=0;
strings1="",s2="";
s1=textBox2.Text;
s2=textBox3.Text;
if(textBox1.Text.Length==0)
i=0;
else
i=Convert.ToInt16(textBox1.Text);
SqlConnectionobjSqlConnection=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
objSqlConnection.Open();
MessageBox.Show("数据库连接成功","好");
try
{
SqlCommandsqlcom=newSqlCommand("deletefrominfowhereid="+i,objSqlConnection);

sqlcom.ExecuteNonQuery();

MessageBox.Show("删除成功！","啊");

objSqlConnection.Close();
}
catch(Exceptiona)
{
MessageBox.Show(a.ToString());
}

五：数据库的查询代码：

1.类开始：

DataTabledt1=newDataTable();
SqlDataAdapterda1=newSqlDataAdapter();

2.按钮代码：

inti=0,n=0;
strings1="",s2="";
s1=textBox2.Text;
s2=textBox3.Text;
if(textBox1.Text.Length==0)
i=0;
else
i=Convert.ToInt32(textBox1.Text);
SqlConnectionobjSqlConnection=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
objSqlConnection.Open();
MessageBox.Show("数据库连接成功","好");

stringquery="SELECT*frominfowhereid="+i;

DataSetobjDataSet=newDataSet();

SqlDataAdapterobj=newSqlDataAdapter();

obj.SelectCommand=newSqlCommand(query,objSqlConnection);

obj.Fill(objDataSet,"info");

SqlCommandobjSqlCommand=newSqlCommand(query,objSqlConnection);

SqlDataReaderobjSqlReader=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：C#数据库查询代码：

inti=0;
//intn=0;
strings1="",s2="";
stringsql;
s1=textBox2.Text;
s2=textBox3.Text;

if(textBox1.Text.Length==0)
{
i=0;

}
else
i=Convert.ToInt32(textBox1.Text);
SqlConnectionobjSqlConnection=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
objSqlConnection.Open();
MessageBox.Show("数据库连接成功","好");
stringquery="SELECT*frominfowhereid="+i;
if(i==0)
sql="select*frominfo";
else
sql="select*frominfowhereid="+i;
da1=newSqlDataAdapter(sql,objSqlConnection);
dt1.Clear();
da1.Fill(dt1);
dataGridView1.DataSource=dt1;

C#数据库查询之数据库的封装类代码：

classDBClass
{

publicvoiddbclass(stringsql)
{
try
{
SqlConnectionsqlcon=newSqlConnection("server=127.0.0.1;uid=sa;pwd=;database=test");
sqlcon.Open();

SqlTransactionobjt=sqlcon.BeginTransaction();//事物开始

SqlCommandsqlcom=newSqlCommand(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(Exceptiona)
{
MessageBox.Show(a.ToString());
}

}
}
--db2数据库连接代码：
stringstrcon="Provider=IBMDADB2;DataSource=hfzd;UserId=db2admin;Password=db2admin";
//stringsql="select*fromADMINISTRATOR.HFZD";
stringsql="deletefromADMINISTRATOR.HFZDwhereID=1";
OleDbConnectionolecon=newOleDbConnection(strcon);
olecon.Open();
MessageBox.Show("数据库已连接上");
dt.Clear();
da=newOleDbDataAdapter(sql,olecon);
da.Fill(dt);
dataGridView1.DataSource=dt;
olecon.Close();