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();
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