用SqlCommandBuilder 实现批量更新
2008-08-22 14:11
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1.注意sql语句:是检索整个表的所有数据
select * from tbtest
2. 用SqlCommandBuilder 实现批量更新
3.什么时候用?
a. 有时候需要缓存的时候,比如说在一个商品选择界面,选择好商品,并且进行编辑/删除/更新后,
最后一并交给数据库,而不是每一步操作都访问数据库,因为客户选择商品可能进行n次编辑/删除
更新操作,如果每次都提交,不但容易引起数据库冲突,引发错误,而且当数据量很大时在用户执行
效率上也变得有些慢
b.有的界面是这样的有的界面是这样的,需求要求一定用缓存实现,确认之前的操作不提交到库,点击
页面专门提交的按钮时才提交商品选择信息和商品的其它信息. 我经常遇到这样的情况
c.有些情况下只往数据库里更新,不读取. 也就是说没有从数据库里读,SqlDataAdapter也就不知道是
更新哪张表了,调用Update就很可能出错了。这样的情况下可以用SqlCommandBuilder 了.
4.
注意点:
1.只能更新一个表,如果此数据集是从两个或者两个以上的表关联而来的,则不能用此方法自动更新
2.表中必须设置主键
3.更新的表中字段不能有image类型的
5.优点:
节省代码量,节省时间,这个方法可以代替所有的: 更新/删除/插入操作语句
6.缺点:
访问两次数据库(select * TableName,就是这句,要确认是哪个表,除非是很大的数据量,
一般是感觉不到的),效率稍微有些慢
1.功能:
可以实现你对DataSet在UI层做任意操作后,直接丢给这个方法,这个方法就可以自动把你的修改更 新到数 据库中,而没必要每次都更新到
数据库
2.使用方法
public DataSetUpdateByDataSet(DataSet ds,string strTblName,string strConnection)
{
SqlConnection conn = new SqlConnection(strConnection));
SqlDataAdapter myAdapter = new SqlDataAdapter();
SqlCommand myCommand = new SqlCommand("select * from "+strTblName),(SqlConnection) conn);
myAdapter.SelectCommand = myCommand;
SqlCommandBuilder myCommandBuilder = new SqlCommandBuilder(myAdapter);
try
{
lock(this) //处理并发情况(分布式情况)
{
myAdapter.Update(ds,strTblName);
}
}
catch(Exception err)
{
conn.Close();
throw new BusinessException(err);
}
return ds; //数据集的行状态在更新后会都变为: UnChange,在这次更新后客户端要用返回的ds
}
或
public DataSet UpdateByDataSet(DataSet ds,string strTblName,string strConnection)
{
SqlConnection conn = new SqlConnection(strConnection));
SqlCommand myCommand = new SqlCommand("select * from "+strTblName),(SqlConnection) conn);
SqlDataAdapter myAdapter = new SqlDataAdapter(myCommand );
SqlCommandBuilder myCommandBuilder = new SqlCommandBuilder(myAdapter);
myAdapter.InsertCommand = myCommandBuilder .GetInsertCommand();
myAdapter.UpdateCommand = myCommandBuilder .GetUpdateCommand();
myAdapter.DeleteCommand = myCommandBuilder .GetDeleteCommand();
try
{
lock(this) //处理并发情况(分布式情况)
{
conn.Open();
myAdapter.Update(ds,strTblName);
conn.Close();
}
return ds; //数据集的行状态在更新后会都变为: UnChange,在这次更新后客户端要用返回的ds }
catch(Exception err)
{
conn.Close();
throw new BusinessException(err);
}
}
Private Sub UseCommandBuilder()
Dim connectionString As String = _
"Integrated Security=SSPI;Persist Security Info=False;" + _
"Initial Catalog=Northwind;Data Source=LAP800"
Dim connection As SqlConnection = _
New SqlConnection(connectionString)
connection.Open()
Try
Dim command As SqlCommand = _
New SqlCommand("SELECT * FROM Customers", connection)
Dim adapter As SqlDataAdapter = _
New SqlDataAdapter(command)
Dim builder As SqlCommandBuilder = _
New SqlCommandBuilder(adapter)
' Show commands
Console.WriteLine(builder.GetInsertCommand().CommandText)
Console.WriteLine(builder.GetUpdateCommand().CommandText)
Console.WriteLine(builder.GetDeleteCommand().CommandText)
Dim table As DataTable = New DataTable
adapter.Fill(table)
'Use Insert
Dim row As DataRow = table.NewRow
row("CustomerID") = "PAULK"
row("CompanyName") = "Pauly's Edibles"
row("ContactName") = "Paul Kimmel"
row("ContactTitle") = "The Fat Man"
table.Rows.Add(row)
'Use Update
Dim results() As DataRow = _
table.Select("CustomerID = 'ALFKI'")
results(0)("Region") = "DE"
'Use Delete
Dim deleteThese() As DataRow = _
table.Select("CustomerID = 'FARLA'")
For Each row In deleteThese
row.Delete()
Next
adapter.Update(table)
table.AcceptChanges()
Catch ex As Exception
Debug.WriteLine(ex.Message)
Throw
Finally
connection.Close()
End Try
End Sub
End Module
select * from tbtest
2. 用SqlCommandBuilder 实现批量更新
3.什么时候用?
a. 有时候需要缓存的时候,比如说在一个商品选择界面,选择好商品,并且进行编辑/删除/更新后,
最后一并交给数据库,而不是每一步操作都访问数据库,因为客户选择商品可能进行n次编辑/删除
更新操作,如果每次都提交,不但容易引起数据库冲突,引发错误,而且当数据量很大时在用户执行
效率上也变得有些慢
b.有的界面是这样的有的界面是这样的,需求要求一定用缓存实现,确认之前的操作不提交到库,点击
页面专门提交的按钮时才提交商品选择信息和商品的其它信息. 我经常遇到这样的情况
c.有些情况下只往数据库里更新,不读取. 也就是说没有从数据库里读,SqlDataAdapter也就不知道是
更新哪张表了,调用Update就很可能出错了。这样的情况下可以用SqlCommandBuilder 了.
4.
注意点:
1.只能更新一个表,如果此数据集是从两个或者两个以上的表关联而来的,则不能用此方法自动更新
2.表中必须设置主键
3.更新的表中字段不能有image类型的
5.优点:
节省代码量,节省时间,这个方法可以代替所有的: 更新/删除/插入操作语句
6.缺点:
访问两次数据库(select * TableName,就是这句,要确认是哪个表,除非是很大的数据量,
一般是感觉不到的),效率稍微有些慢
1.功能:
可以实现你对DataSet在UI层做任意操作后,直接丢给这个方法,这个方法就可以自动把你的修改更 新到数 据库中,而没必要每次都更新到
数据库
2.使用方法
public DataSetUpdateByDataSet(DataSet ds,string strTblName,string strConnection)
{
SqlConnection conn = new SqlConnection(strConnection));
SqlDataAdapter myAdapter = new SqlDataAdapter();
SqlCommand myCommand = new SqlCommand("select * from "+strTblName),(SqlConnection) conn);
myAdapter.SelectCommand = myCommand;
SqlCommandBuilder myCommandBuilder = new SqlCommandBuilder(myAdapter);
try
{
lock(this) //处理并发情况(分布式情况)
{
myAdapter.Update(ds,strTblName);
}
}
catch(Exception err)
{
conn.Close();
throw new BusinessException(err);
}
return ds; //数据集的行状态在更新后会都变为: UnChange,在这次更新后客户端要用返回的ds
}
或
public DataSet UpdateByDataSet(DataSet ds,string strTblName,string strConnection)
{
SqlConnection conn = new SqlConnection(strConnection));
SqlCommand myCommand = new SqlCommand("select * from "+strTblName),(SqlConnection) conn);
SqlDataAdapter myAdapter = new SqlDataAdapter(myCommand );
SqlCommandBuilder myCommandBuilder = new SqlCommandBuilder(myAdapter);
myAdapter.InsertCommand = myCommandBuilder .GetInsertCommand();
myAdapter.UpdateCommand = myCommandBuilder .GetUpdateCommand();
myAdapter.DeleteCommand = myCommandBuilder .GetDeleteCommand();
try
{
lock(this) //处理并发情况(分布式情况)
{
conn.Open();
myAdapter.Update(ds,strTblName);
conn.Close();
}
return ds; //数据集的行状态在更新后会都变为: UnChange,在这次更新后客户端要用返回的ds }
catch(Exception err)
{
conn.Close();
throw new BusinessException(err);
}
}
Private Sub UseCommandBuilder()
Dim connectionString As String = _
"Integrated Security=SSPI;Persist Security Info=False;" + _
"Initial Catalog=Northwind;Data Source=LAP800"
Dim connection As SqlConnection = _
New SqlConnection(connectionString)
connection.Open()
Try
Dim command As SqlCommand = _
New SqlCommand("SELECT * FROM Customers", connection)
Dim adapter As SqlDataAdapter = _
New SqlDataAdapter(command)
Dim builder As SqlCommandBuilder = _
New SqlCommandBuilder(adapter)
' Show commands
Console.WriteLine(builder.GetInsertCommand().CommandText)
Console.WriteLine(builder.GetUpdateCommand().CommandText)
Console.WriteLine(builder.GetDeleteCommand().CommandText)
Dim table As DataTable = New DataTable
adapter.Fill(table)
'Use Insert
Dim row As DataRow = table.NewRow
row("CustomerID") = "PAULK"
row("CompanyName") = "Pauly's Edibles"
row("ContactName") = "Paul Kimmel"
row("ContactTitle") = "The Fat Man"
table.Rows.Add(row)
'Use Update
Dim results() As DataRow = _
table.Select("CustomerID = 'ALFKI'")
results(0)("Region") = "DE"
'Use Delete
Dim deleteThese() As DataRow = _
table.Select("CustomerID = 'FARLA'")
For Each row In deleteThese
row.Delete()
Next
adapter.Update(table)
table.AcceptChanges()
Catch ex As Exception
Debug.WriteLine(ex.Message)
Throw
Finally
connection.Close()
End Try
End Sub
End Module
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