C#数据库查询和操作大全-数据库查询操作

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();

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