Membuat jenis yang ditentukan pengguna

Berlaku untuk:SQL Server

Untuk membuat jenis yang ditentukan pengguna (UDT) yang mampu diinstal di SQL Server, Anda harus terlebih dahulu membuat kelas di salah satu bahasa pemrograman .NET Framework yang didukung, seperti C# atau Visual Basic .NET, yang sesuai dengan spesifikasi untuk membuat UDT. Kelas kemudian dapat dikompilasi sebagai pustaka tautan dinamis (DLL), yang dapat dimuat di SQL Server. Anda juga dapat membuat dan menyebarkan UDT menggunakan Visual Studio.

Kemampuan untuk menjalankan kode runtime bahasa umum (CLR) diatur ke NONAKTIF secara default di SQL Server. CLR dapat diaktifkan dengan menggunakan prosedur tersimpan sistem sp_configure, seperti yang ditunjukkan dalam pernyataan Transact-SQL berikut:

EXECUTE sp_configure 'clr enabled', 1;
RECONFIGURE;

Di bagian ini

Artikel	Deskripsi
persyaratan Jenis yang ditentukan pengguna (UDT)	Menjelaskan persyaratan untuk pengkodean jenis yang ditentukan pengguna.
Membuat jenis yang ditentukan pengguna dengan ADO.NET	Menunjukkan teknik pengkodean yang terlibat dalam pembuatan jenis yang ditentukan pengguna.

Contoh

Daftar kode berikut mendefinisikan UDT Point, yang dijelaskan secara rinci dalam Membuat jenis yang ditentukan pengguna dengan ADO.NET.

C#

using System;
using System.Data;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;
using System.Text;

[Serializable]
[Microsoft.SqlServer.Server.SqlUserDefinedType(Format.Native,
     IsByteOrdered=true, ValidationMethodName = "ValidatePoint")]
public struct Point : INullable
{
    private bool is_Null;
    private Int32 _x;
    private Int32 _y;

    public bool IsNull
    {
        get
        {
            return (is_Null);
        }
    }

    public static Point Null
    {
        get
        {
            Point pt = new Point();
            pt.is_Null = true;
            return pt;
        }
    }

    // Use StringBuilder to provide string representation of UDT.
    public override string ToString()
    {
        // Since InvokeIfReceiverIsNull defaults to 'true'
        // this test is unnecessary if Point is only being called
        // from SQL.
        if (this.IsNull)
            return "NULL";
        else
        {
            StringBuilder builder = new StringBuilder();
            builder.Append(_x);
            builder.Append(",");
            builder.Append(_y);
            return builder.ToString();
        }
    }

    [SqlMethod(OnNullCall = false)]
    public static Point Parse(SqlString s)
    {
        // With OnNullCall=false, this check is unnecessary if
        // Point only called from SQL.
        if (s.IsNull)
            return Null;

        // Parse input string to separate out points.
        Point pt = new Point();
        string[] xy = s.Value.Split(",".ToCharArray());
        pt.X = Int32.Parse(xy[0]);
        pt.Y = Int32.Parse(xy[1]);

        // Call ValidatePoint to enforce validation
        // for string conversions.
        if (!pt.ValidatePoint())
            throw new ArgumentException("Invalid XY coordinate values.");
        return pt;
    }

    // X and Y coordinates exposed as properties.
    public Int32 X
    {
        get
        {
            return this._x;
        }
        // Call ValidatePoint to ensure valid range of Point values.
        set
        {
            Int32 temp = _x;
            _x = value;
            if (!ValidatePoint())
            {
                _x = temp;
                throw new ArgumentException("Invalid X coordinate value.");
            }
        }
    }

    public Int32 Y
    {
        get
        {
            return this._y;
        }
        set
        {
            Int32 temp = _y;
            _y = value;
            if (!ValidatePoint())
            {
                _y = temp;
                throw new ArgumentException("Invalid Y coordinate value.");
            }
        }
    }

    // Validation method to enforce valid X and Y values.
    private bool ValidatePoint()
    {
        // Allow only zero or positive integers for X and Y coordinates.
        if ((_x >= 0) && (_y >= 0))
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    // Distance from 0 to Point method.
    [SqlMethod(OnNullCall = false)]
    public Double Distance()
    {
        return DistanceFromXY(0, 0);
    }

    // Distance from Point to the specified point method.
    [SqlMethod(OnNullCall = false)]
    public Double DistanceFrom(Point pFrom)
    {
        return DistanceFromXY(pFrom.X, pFrom.Y);
    }

    // Distance from Point to the specified x and y values method.
    [SqlMethod(OnNullCall = false)]
    public Double DistanceFromXY(Int32 iX, Int32 iY)
    {
        return Math.Sqrt(Math.Pow(iX - _x, 2.0) + Math.Pow(iY - _y, 2.0));
    }
}

Visual Basic .NET

Option Explicit On
Option Strict On

Imports System
Imports System.Data.SqlTypes
Imports Microsoft.SqlServer.Server
Imports System.Text

<Serializable(), SqlUserDefinedTypeAttribute(Format.Native, _
  IsByteOrdered:=True, _
  ValidationMethodName:="ValidatePoint")> _
  Public Structure Point
    Implements INullable

    Private is_Null As Boolean
    Private _x As Int32
    Private _y As Int32

    Public ReadOnly Property IsNull() As Boolean _
       Implements INullable.IsNull
        Get
            Return (is_Null)
        End Get
    End Property

    Public Shared ReadOnly Property Null() As Point
        Get
            Dim pt As New Point
            pt.is_Null = True
            Return (pt)
        End Get
    End Property

    ' Use StringBuilder to provide string representation of UDT.
    Public Overrides Function ToString() As String
        ' Since InvokeIfReceiverIsNull defaults to 'true'
        ' this test is unnecessary if Point is only being called
        ' from SQL.
        If Me.IsNull Then
            Return "NULL"
        Else
            Dim builder As StringBuilder = New StringBuilder
            builder.Append(_x)
            builder.Append(",")
            builder.Append(_y)
            Return builder.ToString
        End If
    End Function

    <SqlMethod(OnNullCall:=False)> _
    Public Shared Function Parse(ByVal s As SqlString) As Point
        ' With OnNullCall=False, this check is unnecessary if
        ' Point only being called from SQL.
        If s.IsNull Then
            Return Null
        End If

        ' Parse input string here to separate out points.
        Dim pt As New Point()
        Dim xy() As String = s.Value.Split(",".ToCharArray())
        pt.X = Int32.Parse(xy(0))
        pt.Y = Int32.Parse(xy(1))

        ' Call ValidatePoint to enforce validation
        ' for string conversions.
        If Not pt.ValidatePoint() Then
            Throw New ArgumentException("Invalid XY coordinate values.")
        End If
        Return pt
    End Function

    ' X and Y coordinates are exposed as properties.
    Public Property X() As Int32
        Get
            Return (Me._x)
        End Get

        Set(ByVal Value As Int32)
            Dim temp As Int32 = _x
            _x = Value
            If Not ValidatePoint() Then
                _x = temp
                Throw New ArgumentException("Invalid X coordinate value.")
            End If
        End Set
    End Property

    Public Property Y() As Int32
        Get
            Return (Me._y)
        End Get

        Set(ByVal Value As Int32)
            Dim temp As Int32 = _y
            _y = Value
            If Not ValidatePoint() Then
                _y = temp
                Throw New ArgumentException("Invalid Y coordinate value.")
            End If
        End Set
    End Property

    ' Validation method to enforce valid X and Y values.
    Private Function ValidatePoint() As Boolean
        ' Allow only zero or positive integers for X and Y coordinates.
        If (_x >= 0) And (_y >= 0) Then
            Return True
        Else
            Return False
        End If
    End Function

    ' Distance from 0 to Point method.
    <SqlMethod(OnNullCall:=False)> _
  Public Function Distance() As Double
        Return DistanceFromXY(0, 0)
    End Function

    ' Distance from Point to the specified point method.
    <SqlMethod(OnNullCall:=False)> _
    Public Function DistanceFrom(ByVal pFrom As Point) As Double
        Return DistanceFromXY(pFrom.X, pFrom.Y)
    End Function

    ' Distance from Point to the specified x and y values method.
    <SqlMethod(OnNullCall:=False)> _
    Public Function DistanceFromXY(ByVal ix As Int32, ByVal iy As Int32) _
        As Double
        Return Math.Sqrt(Math.Pow(ix - _x, 2.0) + Math.Pow(iy - _y, 2.0))
    End Function
End Structure

Konten terkait

• jenis yang ditentukan pengguna CLR