通过

How to: Set Default Initialization Fields in Visual Basic .NET

  • 项目

This section describes how to optimize SMO object property initialization in Visual Basic .NET.

The code example shows how to minimize the number of object properties initialized in an SMO program. You have to include the using System.Collections.Specialized; statement to use the StringCollection object.

Microsoft SQL Server Profiler can be used to compare the number statements sent to the instance of Microsoft SQL Server with this optimization.

Setting default initialization fields

  1. Start Visual Studio 2005.

  2. From the File menu, select New Project. The New Project dialog box appears.

  3. In the Project Types pane, select Visual Basic. In the Templates pane, select Console Application.

  4. (Optional) In the Name box, type the name of the new application.

  5. Click OK to load the Visual Basic console application template.

  6. On the Project menu, select Add Reference item. The Add Reference dialog box appears. Select Browse and locate the SMO assemblies in the C:\Program Files\Microsoft SQL Server\90\SDK\Assemblies folder. Select the following files:

    Microsoft.SqlServer.ConnectionInfo.dll

    Microsoft.SqlServer.Smo.dll

    Microsoft.SqlServer.SqlEnum.dll

    Microsoft.SqlServer.SmoEnum.dll

  7. On the View menu, click Code.-Or-Select the Module1.vb window to display the code window.

  8. In the code, before any declarations, type the following Imports statements to qualify the types in the SMO namespace:

    Imports Microsoft.SqlServer.Management.Smo
Imports Microsoft.SqlServer.Management.Common

  9. Insert the code that follows this procedure into the main program.

  10. Run and build the application.

示例

'Connect to the local, default instance of SQL Server.
Dim srv As Server
srv = New Server
'Reference the AdventureWorks database.
Dim db As Database
db = srv.Databases("AdventureWorks")
'Assign the Table object type to a System.Type object variable.
Dim tb As Table
Dim typ As Type
tb = New Table
typ = tb.GetType
'Assign the current default initialization fields for the Table object type to a 
'StringCollection object variable.
Dim sc As StringCollection
sc = srv.GetDefaultInitFields(typ)
'Set the default initialization fields for the Table object type to the CreateDate property.
srv.SetDefaultInitFields(typ, "CreateDate")
'Retrieve the Schema, Name, and CreateDate properties for every table in AdventureWorks.
'Note that the improvement in performance can be viewed in SQL Profiler.
For Each tb In db.Tables
    Console.WriteLine(tb.Schema + "." + tb.Name + " " + tb.CreateDate)
Next
'Set the default initialization fields for the Table object type back to the original settings.
srv.SetDefaultInitFields(typ, sc)