僅使用預存程式存取數據是常見的案例。
範例
說明
您可以使用使用預存程式來自定義作業中提供的範例，將第一個查詢（該查詢導致動態 SQL 的執行）替換為使用預存程式的方法呼叫。
假設 CustomersByCity 是 方法，如下列範例所示。
程式碼
[Function()]
public IEnumerable<Customer> CustomersByCity(
[Parameter(Name = "City", DbType = "NVarChar(15)")]
string city)
{
IExecuteResult result = this.ExecuteMethodCall(this,
((MethodInfo)(MethodInfo.GetCurrentMethod())),
city);
return ((IEnumerable<Customer>)(result.ReturnValue));
}
<[Function]()> _
Public Function CustomersByCity( _
<Parameter(Name:="City", DbType:="NVarChar(15)")> ByVal _
city As String) As IEnumerable(Of Customer)
Dim result = Me.ExecuteMethodCall(Me, _
(CType(MethodInfo.GetCurrentMethod(), IEnumerable(Of _
Customer))), city)
Return CType(result.ReturnValue, IEnumerable(Of Customer))
End Function
下列程式代碼會在沒有任何動態 SQL 的情況下執行。
NorthwindThroughSprocs db = new NorthwindThroughSprocs("...");
// Use a method call (stored procedure wrapper) instead of
// a LINQ query against the database.
var custQuery =
db.CustomersByCity("London");
foreach (Customer custObj in custQuery)
{
// Deferred loading of custObj.Orders uses the override
// LoadOrders. There is no dynamic SQL.
foreach (Order ord in custObj.Orders)
{
// Make some changes to customers/orders.
// Overrides for Customer are called during the execution
// of the following.
}
}
db.SubmitChanges();
Dim db As New Northwind("...")
' Use a method call (stored procedure wrapper) instead of
' a LINQ query against the database.
Dim custQuery = db.CustomersByCity("London")
For Each custObj In custQuery
' Deferred loading of custObj.Orders uses the override
' LoadOrders. There is no dynamic SQL.
For Each ord In custObj.Orders
' Make some changes to customers/orders.
' Overrides for Customer are called during the execution
' of the following:
db.SubmitChanges()
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