PrecedenceConstraint.EvalOp 属性
定义
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
获取或设置优先约束使用的求值运算。
public:
property Microsoft::SqlServer::Dts::Runtime::DTSPrecedenceEvalOp EvalOp { Microsoft::SqlServer::Dts::Runtime::DTSPrecedenceEvalOp get(); void set(Microsoft::SqlServer::Dts::Runtime::DTSPrecedenceEvalOp value); };[Microsoft.SqlServer.Dts.Runtime.Localization.LocalizablePropertyDescription(typeof(Microsoft.SqlServer.Dts.Runtime.Localized), "PCEvalOpDesc")]
public Microsoft.SqlServer.Dts.Runtime.DTSPrecedenceEvalOp EvalOp { get; set; }[<Microsoft.SqlServer.Dts.Runtime.Localization.LocalizablePropertyDescription(typeof(Microsoft.SqlServer.Dts.Runtime.Localized), "PCEvalOpDesc")>]
member this.EvalOp : Microsoft.SqlServer.Dts.Runtime.DTSPrecedenceEvalOp with get, setPublic Property EvalOp As DTSPrecedenceEvalOp属性值
DTSPrecedenceEvalOp 枚举中的一个值。
- 属性
示例
下面的代码示例创建三个任务，并使用优先约束连接它们。 然后，该示例循环访问包集合中的 PrecedenceConstraints 约束，并打印有关每个约束的信息。
using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.SqlServer.Dts.Runtime;
namespace PrecedenceConst
{
class Program
{
static void Main(string[] args)
{
Package pkg = new Package();
// Add a File System task.
Executable eFileTask1 = pkg.Executables.Add("STOCK:FileSystemTask");
TaskHost thFileTask1 = eFileTask1 as TaskHost;
// Add a second File System task.
Executable eFileTask2 = pkg.Executables.Add("STOCK:FileSystemTask");
TaskHost thFileTask2 = eFileTask2 as TaskHost;
// Add a Bulk Insert task.
Executable eBulkInsert = pkg.Executables.Add("STOCK:BulkInsertTask");
TaskHost thBulkInsert = eBulkInsert as TaskHost;
// Add a precedence contraint between eFileTask1 and eFileTask2.
// Set the constraint to be that eFileTask2 cannot run
// until eFileTask1 completes.
PrecedenceConstraint pcFileTasks = pkg.PrecedenceConstraints.Add(eFileTask1, eFileTask2);
// Add another precedence contraint. Add it between eFileTask2 and BulkInsert.
// Again, set the constraint to be that BulkInsert cannot run
// until eFileTask2 completes.
PrecedenceConstraint pcFiletoBulk = pkg.PrecedenceConstraints.Add(eFileTask2, eBulkInsert);
// Obtain the precedence constraint collection, and display properties.
// Some properties are read/write and have not been set.
PrecedenceConstraints pConsts = pkg.PrecedenceConstraints;
foreach (PrecedenceConstraint pc in pConsts)
{
Console.WriteLine("Constrained container {0}", pc.ConstrainedExecutable);
Console.WriteLine("Creation Name {0}", pc.CreationName);
Console.WriteLine("Description {0}", pc.Description);
Console.WriteLine("Evaluation operation {0}", pc.EvalOp);
Console.WriteLine("Evaluates true {0}", pc.EvaluatesTrue);
Console.WriteLine("Expression {0}", pc.Expression);
Console.WriteLine("ID {0}", pc.ID);
Console.WriteLine("LogicalAnd {0}", pc.LogicalAnd);
Console.WriteLine("Name {0}", pc.Name);
Console.WriteLine("Precedence Executable {0}", pc.PrecedenceExecutable);
Console.WriteLine("Value {0}", pc.Value);
Console.WriteLine("-----------------------------------");
}
}
}
}
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports Microsoft.SqlServer.Dts.Runtime
Namespace PrecedenceConst
Class Program
Shared Sub Main(ByVal args() As String)
Dim pkg As Package = New Package()
' Add a File System task.
Dim eFileTask1 As Executable = pkg.Executables.Add("STOCK:FileSystemTask")
Dim thFileTask1 As TaskHost = eFileTask1 as TaskHost
' Add a second File System task.
Dim eFileTask2 As Executable = pkg.Executables.Add("STOCK:FileSystemTask")
Dim thFileTask2 As TaskHost = eFileTask2 as TaskHost
' Add a Bulk Insert task.
Dim eBulkInsert As Executable = pkg.Executables.Add("STOCK:BulkInsertTask")
Dim thBulkInsert As TaskHost = eBulkInsert as TaskHost
' Add a precedence contraint between eFileTask1 and eFileTask2.
' Set the constraint to be that eFileTask2 cannot run
' until eFileTask1 completes.
Dim pcFileTasks As PrecedenceConstraint = pkg.PrecedenceConstraints.Add(eFileTask1,eFileTask2)
' Add another precedence contraint. Add it between eFileTask2 and BulkInsert.
' Again, set the constraint to be that BulkInsert cannot run
' until eFileTask2 completes.
Dim pcFiletoBulk As PrecedenceConstraint = pkg.PrecedenceConstraints.Add(eFileTask2,eBulkInsert)
' Obtain the precedence constraint collection, and display properties.
' Some properties are read/write and have not been set.
Dim pConsts As PrecedenceConstraints = pkg.PrecedenceConstraints
Dim pc As PrecedenceConstraint
For Each pc In pConsts
Console.WriteLine("Constrained container {0}", pc.ConstrainedExecutable)
Console.WriteLine("Creation Name {0}", pc.CreationName)
Console.WriteLine("Description {0}", pc.Description)
Console.WriteLine("Evaluation operation {0}", pc.EvalOp)
Console.WriteLine("Evaluates true {0}", pc.EvaluatesTrue)
Console.WriteLine("Expression {0}", pc.Expression)
Console.WriteLine("ID {0}", pc.ID)
Console.WriteLine("LogicalAnd {0}", pc.LogicalAnd)
Console.WriteLine("Name {0}", pc.Name)
Console.WriteLine("Precedence Executable {0}", pc.PrecedenceExecutable)
Console.WriteLine("Value {0}", pc.Value)
Console.WriteLine("-----------------------------------")
Next
End Sub
End Class
End Namespace
示例输出：
受约束的容器 Microsoft.SqlServer.Dts.Runtime.TaskHost
创建名称
说明
评估操作约束
计算 true True
Expression
ID {BA20A288-545D-4E48-864A-E6AF6C3B9AEE}
LogicalAnd True
名称 {BA20A288-545D-4E48-864A-E6AF6C3B9AEE}
优先级可执行文件 Microsoft.SqlServer.Dts.Runtime.TaskHost
值成功
-----------------------------------
受约束的容器 Microsoft.SqlServer.Dts.Runtime.TaskHost
创建名称
说明
评估操作约束
计算 true True
Expression
ID {E8DBC95E-AF27-45D7-B961-17E908CC4530}
LogicalAnd True
名称 {E8DBC95E-AF27-45D7-B961-17E908CC4530}
优先级可执行文件 Microsoft.SqlServer.Dts.Runtime.TaskHost
值成功
-----------------------------------
注解
枚举中的值
优先约束链接两个可执行文件：优先可执行文件和受约束的可执行文件。 优先可执行文件先于受约束的可执行文件运行，而优先可执行文件的执行结果可能决定受约束的可执行文件是否运行。 优先可执行文件的执行结果是否确定受约束的可执行文件是否依赖于此属性设置。