DataBase和DataSet的区别有什么？

Command对象
SelectCommand:用来获取数据源中的记录；
InsertCommand:用来向数据源中新插入一条记录；
UpateCommand:用来更新数据源中的数据；
DeleteCommand:用来删除数据源中的记录；

private void Page_Load(object sender, System.EventArgs e)
{
sqlDataAdapter1.Fill(dsEmployee1);
DataGrid1.DataBind();
}


DataRowVersion
在调用DataRow对象的BeginEdit方法之后，如果更改该值，则Current和Proposed值变得可用。
在调用DataRow对象的CancelEdit方法之后，Proposed值将被删除。
在调用DataRow对象的EndEdit方法之后，Proposed值变成Current值。
在调用DataRow对象的AcceptChanges方法之后，Original值变得与Current值相同。
在调用DataTeble对象的AcceptChanges方法之后，Original值变得与Current值相同。
在调用DataRow对象的RejectChanges之后，Proposed值将被丢弃，版本变成Current。

Fill方法
Fill(DataSet):用数据源返回的行填充指定数据集
Fill(DataTable):
Fill(DataSet,tableName):在指定的数据集中，用数据源返回的行填充称为tableName的数据表
Fill(DataTable,DataReader):用指定的DataReader填充数据表

DataAdpter的常用案例
private void Page_Load(object sender, System.EventArgs e)
{
if(!IsPostBack)
myBind(0);
}
private void myBind(int nIndex)
{
string strCon =System.Configuration.ConfigurationSettings.AppSettings["DSN"];
SqlConnection con = new SqlConnection(strCon);
//首先绑定ddlClassCode
SqlDataAdapter da = new SqlDataAdapter("select Distinct classCode from tbClassInfo",con);
DataSet ds = new DataSet("myDs");
da.Fill(ds,"Class");
ddlClassCode.DataTextField = "ClassCode";
ddlClassCode.DataSource = ds.Tables["Class"].DefaultView;
ddlClassCode.DataBind();
ddlClassCode.SelectedIndex = nIndex;
string strSelectedClass = ddlClassCode.SelectedItem.Text;
string strSql = "select * from tbStudentInfo where StudentID in (select studentid from tbClassInfo where classcode='"+strSelectedClass+"')";
da.SelectCommand.CommandText =strSql;
////映射
da.TableMappings.Add("tbStudentInfo","Student");
da.TableMappings[0].ColumnMappings.Add("StudentID","学生ID");
da.TableMappings[0].ColumnMappings.Add("StudentName","学生姓名");
da.TableMappings[0].ColumnMappings.Add("StudentPass","密码");
da.TableMappings[0].ColumnMappings.Add("Sex","性别");
da.TableMappings[0].ColumnMappings.Add("BirthDay","生日");
da.TableMappings[0].ColumnMappings.Add("Email","邮件地址");
da.TableMappings[0].ColumnMappings.Add("Score","成绩");
da.Fill(ds,"tbStudentInfo");
dgShow.DataSource = ds.Tables["Student"].DefaultView;
dgShow.DataBind();
}


DataSet ds;
private void Page_Load(object sender, System.EventArgs e)
{
if(!IsPostBack)
{
SqlConnection con = new SqlConnection("Server=(local);uid=sa;pwd=12345678;database=pubs");
con.Open();
SqlCommand com = new SqlCommand("Select Count(authors.au_fname) from"+
"(authors INNER JOIN titleauthor ON authors.au_id = titleauthor.au_id)"+
"INNER JOIN titles ON titleauthor.title_id=titles.title_id",con);
Session["nMax"] =(int)com.ExecuteScalar();
Session["nCurr"] =0;
con.Close();
SqlDataAdapter da = new SqlDataAdapter("Select authors.au_fname ,authors.au_lname,"
+"titles.title from"+
"(authors INNER JOIN titleauthor ON authors.au_id = titleauthor.au_id)"+
"INNER JOIN titles ON titleauthor.title_id=titles.title_id",con);
ds = new DataSet("authors");
da.Fill(ds,0,1,"AuthorAndTitle");
Fill();
Session["da"] = da;
}
}
private void Fill()
{
tbAuthor.Text = ds.Tables["AuthorAndTitle"].Rows[0]["au_fname"]+ " "
+ds.Tables["AuthorAndTitle"].Rows[0]["au_lname"];
tbTitle.Text = ds.Tables["AuthorAndTitle"].Rows[0]["title"].ToString();
}
private void btnPrev_Click(object sender, System.EventArgs e)
{
int iMax = (int)Session["nMax"];
int iCurr = (int)Session["nCurr"];
SqlDataAdapter da = (SqlDataAdapter)Session["da"];
if(iCurr<=iMax)
{
ds = new DataSet("authors");
iCurr++;
da.Fill(ds,iCurr,1,"AuthorAndTitle");
Fill();
}
Session["nCurr"] = iCurr;
}
private void btnNext_Click(object sender, System.EventArgs e)
{
int iMax = (int)Session["nMax"];
int iCurr = (int)Session["nCurr"];
SqlDataAdapter da = (SqlDataAdapter)Session["da"];
if(iCurr>0)
{
ds = new DataSet("authors");
iCurr--;
da.Fill(ds,iCurr,1,"AuthorAndTitle");
Fill();
}
Session["nCurr"] = iCurr;
}

Updata方法
Update(DataSet):根据指定的数据集中的数据表更新数据
Update(DateRows):根据指定的数据行数组更新数据源
Update(DateTable):根据指定的数据表更数据源


使用DataAdpter更新数据库
private void Page_Load(object sender, System.EventArgs e)
{
Bind();
}
private void Bind()
{
SqlConnection nwindConn = new SqlConnection( "server=(local);uid=sa;pwd=12345678;database=Northwind" );
SqlDataAdapter catDA = new SqlDataAdapter("SELECT * FROM Categories", nwindConn);
DataSet catDS = new DataSet();
catDA.Fill(catDS, "Categories");
dgShow.DataSource = catDS.Tables["Categories"].DefaultView;
dgShow.DataBind();
}
private void btnUpdate_Click(object sender, System.EventArgs e)
{
SqlConnection nwindConn = new SqlConnection( "server=(local);uid=sa;pwd=12345678;database=Northwind" );
SqlDataAdapter catDA = new SqlDataAdapter("SELECT * FROM Categories", nwindConn);
catDA.UpdateCommand = new SqlCommand("UPDATE Categories SET CategoryName = @CategoryName " +"WHERE CategoryID = @CategoryID" , nwindConn);
catDA.UpdateCommand.Parameters.Add("@CategoryName", SqlDbType.NVarChar, 15, "CategoryName");
SqlParameter workParm = catDA.UpdateCommand.Parameters.Add("@CategoryID", SqlDbType.Int);
workParm.SourceColumn = "CategoryID";
workParm.SourceVersion = DataRowVersion.Original;
DataSet catDS = new DataSet();
catDA.Fill(catDS, "Categories");
DataRow cRow = catDS.Tables["Categories"].Rows[0];
cRow["CategoryName"] = "NewName";
catDA.Update(catDS,"Categories");
Bind();
}
private void btnAdd_Click(object sender, System.EventArgs e)
{
SqlConnection nwindConn = new SqlConnection( "server=(local);uid=sa;pwd=12345678;database=Northwind" );
SqlDataAdapter catDA = new SqlDataAdapter("SELECT * FROM Categories", nwindConn);
catDA.InsertCommand = new SqlCommand("Insert into Categories(CategoryName,Description) values"
+" (@CategoryName,@Description)", nwindConn);
catDA.InsertCommand.Parameters.Add("@CategoryName", SqlDbType.NVarChar, 15, "CategoryName");
catDA.InsertCommand.Parameters.Add("@Description", SqlDbType.NText, 16, "Description");
DataSet catDS = new DataSet();
catDA.Fill(catDS, "Categories");
DataRow dr = catDS.Tables["Categories"].NewRow();
dr["CategoryName"] = "Added New Name";
dr["Description"] = "my Description";
catDS.Tables["Categories"].Rows.Add(dr);
catDA.Update(catDS,"Categories");
Bind();
}

使用CommandBuilder更新数据库
private void Page_Load(object sender, System.EventArgs e)
{
// Create the DataSet and DataAdapter
SqlConnection myConnection = new SqlConnection( "server=(local);uid=sa;pwd=12345678;database=Pubs" );
DataSet myDataSet = new DataSet();
SqlDataAdapter myDataAdapter = new SqlDataAdapter("Select * From Authors", myConnection );
myDataAdapter.Fill( myDataSet, "Authors" );
dgShow.DataSource = myDataSet.Tables[0].DefaultView;
dgShow.DataBind();
}
private void btnUpdate_Click(object sender, System.EventArgs e)
{
// Create the DataSet and DataAdapter
SqlConnection myConnection = new SqlConnection( "server=(local);uid=sa;pwd=12345678;database=Pubs" );
DataSet myDataSet = new DataSet();
SqlDataAdapter myDataAdapter = new SqlDataAdapter("Select * From Authors", myConnection );
myDataAdapter.Fill( myDataSet, "Authors" );
// Change value of first row
myDataSet.Tables[ "Authors" ].Rows[ 0 ][ "au_fname" ] = "张三";
// Update the Database Table
SqlCommandBuilder myBuilder = new SqlCommandBuilder( myDataAdapter );
myDataAdapter.Update( myDataSet, "Authors" );
dgShow.DataSource = myDataSet.Tables[0].DefaultView;
dgShow.DataBind();
}

数据适配器的事件
OnRowUpdating:在数据行更新前执行
OnRowUpdated:在数据行更新后执行

SqlRowUpdated EventArgs属性
属性 描述
Command 要执行的数据命令
Errors 错误
Row 要更新的行
StatementType 要执行的命令类型，可能为Select、Insert、Delete和Update
RecordsAffected 要响应的行数
TableMapping 更新所使用的DataTableMapping


DataAdapter事件
private void Page_Load(object sender, System.EventArgs e)
{
// Create the DataSet and DataAdapter
SqlConnection myConnection = new SqlConnection( "server=(local);uid=sa;pwd=12345678;database=Pubs" );
DataSet myDataSet = new DataSet();
SqlDataAdapter myDataAdapter = new SqlDataAdapter("Select * From Authors", myConnection );
myDataAdapter.Fill( myDataSet, "Authors" );
dgShow.DataSource = myDataSet.Tables[0].DefaultView;
dgShow.DataBind();
}
private void btnUpdate_Click(object sender, System.EventArgs e)
{
// Create the DataSet and DataAdapter
SqlConnection myConnection = new SqlConnection( "server=(local);uid=sa;pwd=12345678;database=Pubs" );
DataSet myDataSet = new DataSet();
SqlDataAdapter myDataAdapter = new SqlDataAdapter("Select * From Authors", myConnection );
//使用委托
myDataAdapter.RowUpdating += new SqlRowUpdatingEventHandler(MyUpdatingHandler);
myDataAdapter.RowUpdated += new SqlRowUpdatedEventHandler(MyUpdatedHandler);
myDataAdapter.Fill( myDataSet, "Authors" );
// Change value of first row
myDataSet.Tables[ "Authors" ].Rows[ 0 ][ "au_fname" ] = "Johns";
// Update the Database Table
SqlCommandBuilder myBuilder = new SqlCommandBuilder( myDataAdapter );
myDataAdapter.Update( myDataSet, "Authors" );
dgShow.DataSource = myDataSet.Tables[0].DefaultView;
dgShow.DataBind();
}
public void MyUpdatingHandler(object adapter,SqlRowUpdatingEventArgs e)
{
switch(e.StatementType)
{
case StatementType.Update:
{
SqlConnection myConnection = new SqlConnection( "server=(local);uid=sa;pwd=12345678;database=Pubs" );
string strSql = "Select * From Authors where au_fname='"
+e.Row["au_fname",DataRowVersion.Original]+"'";
SqlCommand com = new SqlCommand(strSql,myConnection);
myConnection.Open();
if(com.ExecuteNonQuery()==0)
{
Response.Write("出错！有用户已经修改过数据集!");
e.Status = UpdateStatus.ErrorsOccurred;//报错
}
myConnection.Close();
break;
}
}
}
public void MyUpdatedHandler(object adapter,SqlRowUpdatedEventArgs e)
{
switch(e.StatementType)
{
case StatementType.Update:
if(e.Status==UpdateStatus.ErrorsOccurred)
e.Status = UpdateStatus.SkipCurrentRow;
break;
}
}