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一：C#數據庫查詢之數據庫連接代碼：

 
 
 

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

二：數據庫的添加記錄代碼：

 
 
 

  
  
  
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("數據庫連接成功","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：數據庫的修改代碼：

 
 
 

  
  
  
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("數據庫連接成功","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：數據庫的刪除代碼：

 
 
 

  
  
  
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("數據庫連接成功","好"); 
  
  
  
try
  
  
  
{ 
  
  
  
SqlCommandsqlcom=newSqlCommand("deletefrominfowhereid="+i,objSqlConnection); 
  
  
  

  
  
  
sqlcom.ExecuteNonQuery(); 
  
  
  

  
  
  
MessageBox.Show("刪除成功！","啊"); 
  
  
  

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

五：數據庫的查詢代碼：

1.類開始：

 
 
 

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

2.按鈕代碼：

 
 
 

  
  
  
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("數據庫連接成功","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("編號:"+objSqlReader.Getvalue(0)+"姓名:"+objSqlReader.Getvalue(1)+"性別"+objSqlReader.Getvalue(2)); 
  
  
  
} 
  
  
  
if(n==0) 
  
  
  
MessageBox.Show("數據庫中沒有這樣的記錄！");
 
 
 

六：C#數據庫查詢代碼：

 
 
 

  
  
  
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("數據庫連接成功","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#數據庫查詢之數據庫的封裝類代碼：

 
 
 

  
  
  
classDBClass 
  
  
  
{ 
  
  
  

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

  
  
  
SqlTransactionobjt=sqlcon.BeginTransaction();//事物開始 
  
  
  

  
  
  
SqlCommandsqlcom=newSqlCommand(sql,sqlcon); 
  
  
  

  
  
  
sqlcom.Transaction=objt;//將Command對象設置為事物處理的對象 
  
  
  

  
  
  
sqlcom.ExecuteNonQuery(); 
  
  
  
objt.Commit();//提交事物 
  
  
  
sqlcon.Close(); 
  
  
  
} 
  
  
  
catch(Exceptiona) 
  
  
  
{ 
  
  
  
MessageBox.Show(a.ToString()); 
  
  
  
} 
  
  
  

  
  
  
} 
  
  
  
} 
  
  
  
--db2數據庫連接代碼： 
  
  
  
stringstrcon="Provider=IBMDADB2;DataSource=hfzd;UserId=db2admin;Password=db2admin"; 
  
  
  
//stringsql="select*fromADMINISTRATOR.HFZD"; 
  
  
  
stringsql="deletefromADMINISTRATOR.HFZDwhereID=1"; 
  
  
  
OleDbConnectionolecon=newOleDbConnection(strcon); 
  
  
  
olecon.Open(); 
  
  
  
MessageBox.Show("數據庫已連接上"); 
  
  
  
dt.Clear(); 
  
  
  
da=newOleDbDataAdapter(sql,olecon); 
  
  
  
da.Fill(dt); 
  
  
  
dataGridView1.DataSource=dt; 
  
  
  
olecon.Close();
 
 
 

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