Tipo definito dall'utente

Articolo
05/07/2013

Nell'esempio relativo al tipo di dati definito dall'utente viene illustrato come creare e utilizzare un tipo di dati semplice definito dall'utente sia da Transact-SQL che da un'applicazione client tramite System.Data.SqlClient.

Prerequisiti

Per creare ed eseguire questo progetto, è necessario installare il software seguente:

SQL Server o SQL Server Express. SQL Server Express è disponibile gratuitamente nel sito Web di documentazione ed esempi per SQL Server Express.
Database AdventureWorks, disponibile nel sito Web per sviluppatori di SQL Server.
.NET Framework SDK 2.0 o versione successiva oppure Microsoft Visual Studio 2005 o versione successiva. .NET Framework SDK è disponibile gratuitamente.
È necessario inoltre che siano soddisfatte le condizioni seguenti:
Per l'istanza di SQL Server utilizzata deve essere abilitata l'integrazione con CLR.
Per abilitare l'integrazione con CLR, effettuare le operazioni seguenti:

Abilitazione dell'integrazione con CLR
- Eseguire i comandi Transact-SQL seguenti:
sp_configure 'clr enabled', 1

GO

RECONFIGURE

GO

[!NOTA]

Per abilitare CLR, è necessario disporre dell'autorizzazione ALTER SETTINGS a livello di server, che viene assegnata implicitamente ai membri dei ruoli predefiniti del server sysadmin e serveradmin.
Il database AdventureWorks deve essere installato nell'istanza di SQL Server in uso.
Se non si dispone dei diritti di amministratore per l'istanza di SQL Server in uso, è necessario ricevere da un amministratore l'autorizzazione CreateAssembly per completare l'installazione.

Compilazione dell'esempio

Creare ed eseguire l'esempio tramite le istruzioni seguenti:

Aprire un prompt dei comandi di .NET Framework o Visual Studio.
Se necessario, creare una directory per l'esempio. Per questo esempio verrà utilizzata la directory C:\MySample.
In c:\MySample creare ComplexNumber.vb (per l'esempio Visual Basic) o ComplexNumber.cs (per l'esempio C#) e copiare nel file il codice di esempio appropriato, Visual Basic o C#, riportato di seguito.
Compilare il codice di esempio dal prompt della riga di comando eseguendo una delle istruzioni seguenti, a seconda del linguaggio scelto.
- Vbc /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Data.dll,C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.dll,C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Xml.dll /target:library ComplexNumber.vb
Csc /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Data.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.XML.dll /target:library ComplexNumber.cs
Copiare il codice di installazione Transact-SQL in un file e salvarlo come Install.sql nella directory dell'esempio.
Se l'esempio è installato in una directory diversa da C:\MySample\, modificare il file Install.sql come indicato, in modo che punti al percorso appropriato.
Distribuire l'assembly e la stored procedure eseguendo
- sqlcmd -E -I -i install.sql
Copiare lo script di comandi di test Transact-SQL in un file e salvarlo come test.sql nella directory dell'esempio.
Eseguire lo script di test con il comando seguente
- sqlcmd -E -I -i test.sql
Per eseguire il programma di esempio client (solo C#):
- In c:\MySample creare Program.cs e copiare il codice sorgente nel file.
- Eseguire: Csc /reference:ComplexNumber.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Data.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.XML.dll /out:Client.exe /target:exe Program.cs
- Effettuare un test eseguendo: Client AdventureWorks
Copiare lo script di pulizia Transact-SQL in un file e salvarlo come cleanup.sql nella directory dell'esempio.
Eseguire lo script con il comando seguente
- sqlcmd -E -I -i cleanup.sql

Codice di esempio

Di seguito sono illustrati i listati di codice per l'esempio.

using System;
using System.Data.Sql;
using System.Data.SqlTypes;
using System.Text.RegularExpressions;
using System.Runtime.InteropServices;
using System.Globalization;
    [Serializable]
    [Microsoft.SqlServer.Server.SqlUserDefinedType(Microsoft.SqlServer.Server.Format.Native, IsByteOrdered = false)]
    public struct ComplexNumber : INullable, IComparable
    {
        //Regular expression used to parse values that are of the form (1,2i)
        private static readonly Regex _parser
            = new Regex(@"\A\(\s*(?<real>\-?\d+(\.\d+)?)\s*,\s*(?<img>\-?\d+(\.\d+)?)\s*i\s*\)\Z",
            RegexOptions.Compiled | RegexOptions.ExplicitCapture);

        double _real;

        double _imaginary;

        bool _isnull;

        const string NULL = "<<null complex>>";

        static readonly ComplexNumber NULL_INSTANCE = new ComplexNumber(true);

        public ComplexNumber(double real, double imaginary)
        {
            this._real = real;
            this._imaginary = imaginary;
            this._isnull = false;
        }

        private ComplexNumber(bool isnull)
        {
            this._isnull = isnull;
            this._real = this._imaginary = 0;
        }

        public double Real
        {
            get
            {
                if (this._isnull)
                    throw new InvalidOperationException();

                return this._real;
            }
            set
            {
                this._real = value;
            }
        }

        public double Imaginary
        {
            get
            {
                if (this._isnull)
                    throw new InvalidOperationException();

                return this._imaginary;
            }
            set
            {
                this._imaginary = value;
            }
        }

        public double Modulus
        {
            get
            {
                if (this._isnull)
                    throw new InvalidOperationException();

                return Math.Sqrt(this._real * this._real
                    + this._imaginary * this._imaginary);
            }
        }

        #region value-based equality
        public int CompareTo(object obj)
        {
            if (!(obj is ComplexNumber))
                return -1;

            ComplexNumber c = (ComplexNumber)obj;

            if (this._isnull && c._isnull)
                return 0;

            if (this._isnull || c._isnull)
                return -1;

            if (this._real == c._real && this._imaginary == c._imaginary)
                return 0;

            if (Modulus == c.Modulus) // same modulus but different r/i, force diff
                return -1;

            // arbitrary comparison...semantics for complex numbers not necessarily correct
            return Modulus.CompareTo(c.Modulus);
        }

        public override bool Equals(object obj)
        {
            return this.CompareTo(obj) == 0;
        }

        public override int GetHashCode()
        {
            return Modulus.GetHashCode();
        }

        public static SqlBoolean operator ==(ComplexNumber c1, ComplexNumber c2)
        {
            return c1.Equals(c2);
        }

        public static SqlBoolean operator !=(ComplexNumber c1, ComplexNumber c2)
        {
            return !c1.Equals(c2);
        }

        public static SqlBoolean operator <(ComplexNumber c1, ComplexNumber c2)
        {
            return c1.CompareTo(c2) < 0;
        }

        public static SqlBoolean operator >(ComplexNumber c1, ComplexNumber c2)
        {
            return c1.CompareTo(c2) > 0;
        }

        #endregion

        public override string ToString()
        {
            return this._isnull ? NULL : ("("
                + this._real.ToString(CultureInfo.InvariantCulture) + ","
                + this._imaginary.ToString(CultureInfo.InvariantCulture)
                + "i)");
        }

        public bool IsNull
        {
            get
            {
                return this._isnull;
            }
        }

        public static ComplexNumber Parse(SqlString sqlString)
        {
            string value = sqlString.ToString();

if (sqlString.IsNull || value == NULL)
return new ComplexNumber(true);


            Match m = _parser.Match(value);

            //Get the message from Properties.Resource.
            if (!m.Success)
                throw new ArgumentException("Invalid format for complex number. Format is ( n, mi ) where n and m are floating point numbers");    

            return new ComplexNumber(double.Parse(m.Groups[1].Value,
                CultureInfo.InvariantCulture), double.Parse(m.Groups[2].Value,
                CultureInfo.InvariantCulture));
        }

        public static ComplexNumber Null
        {
            get
            {
                return NULL_INSTANCE;
            }
        }
    }

Visual Basic

Imports Microsoft.SqlServer.Server
Imports Microsoft.VisualBasic
Imports System
Imports System.Collections
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.SqlTypes
Imports System.Diagnostics
Imports System.Globalization
Imports System.Reflection
Imports System.Runtime.InteropServices
Imports System.Text

''' <summary>
''' AssemblyBrowser is a simple utility for composing sql queries over 
''' assembly metadata. It uses a table-valued-function to return
''' a table to SqlServer.
''' </summary>

Public NotInheritable Class AssemblyBrowser
    ''' <summary>
    ''' Get the types in the assembly, as a table
    ''' </summary>
    ''' <param name="name"></param>
    ''' <returns></returns>
    <Microsoft.SqlServer.Server.SqlFunction(FillRowMethodName:="FillTypeRow", Name:="GetTypes", _
        TableDefinition:="FullName nvarchar(256), BaseTypeName nvarchar(256), IsValueType bit, NumFields int, IsSerializable bit, IsISerializable bit, IsLayoutSequential bit, Namespace nvarchar(256), IsPublic bit, IsSealed bit, AssemblyName nvarchar(256)")> _
    Public Shared Function GetTypes(ByVal name As String) As IEnumerable
        Dim e As IEnumerable

        Try
            Dim a As [Assembly] = GetAssembly(name)
            If a Is Nothing Then
                e = New Type(-1) {}
            Else
                e = a.GetTypes()
            End If

        Catch te As ReflectionTypeLoadException
            'could not load some of the types, just return the types that you could load
            e = te.Types
        End Try

        Return e
    End Function

    ''' <summary>
    ''' Called by SQL Server to populate a row in the results of the TVF.  Takes a type and
    ''' breaks the information up into separate columns for the row being generated.
    ''' </summary>
    ''' <param name="row"></param>
    ''' <param name="fullName"></param>
    ''' <param name="baseTypeName"></param>
    ''' <param name="isValueType"></param>
    ''' <param name="numFields"></param>
    ''' <param name="isSerializable"></param>
    ''' <param name="isISerializable"></param>
    ''' <param name="isLayoutSequential"></param>
    ''' <param name="namespace"></param>
    ''' <param name="isPublic"></param>
    ''' <param name="isSealed"></param>
    ''' <param name="assemblyName"></param>
    ''' <remarks></remarks>
    Public Shared Sub FillTypeRow(ByVal row As Object, <Out()> ByRef fullName As String, <Out()> ByRef baseTypeName As String, _
        <Out()> ByRef isValueType As Boolean, <Out()> ByRef numFields As Integer, <Out()> ByRef isSerializable As Boolean, _
        <Out()> ByRef isISerializable As Boolean, <Out()> ByRef isLayoutSequential As Boolean, <Out()> ByRef [namespace] As String, _
        <Out()> ByRef isPublic As Boolean, <Out()> ByRef isSealed As Boolean, <Out()> ByRef assemblyName As String)

        If row Is Nothing Then
            Return
        End If

        Dim t As Type = CType(row, Type)

        fullName = t.FullName
        If (t.BaseType Is Nothing) Then
            baseTypeName = String.Empty
        Else
            baseTypeName = t.BaseType.FullName
        End If

        isValueType = t.IsValueType

        Dim fields As FieldInfo() = t.GetFields(BindingFlags.Instance Or BindingFlags.Public)

        If (fields Is Nothing) Then
            numFields = 0
        Else
            numFields = fields.Length
        End If

        isSerializable = t.IsSerializable
        isISerializable = GetType(System.Runtime.Serialization.ISerializable).IsAssignableFrom(t)
        isLayoutSequential = t.IsLayoutSequential
        [namespace] = t.Namespace
        isPublic = t.IsPublic
        isSealed = t.IsSealed
        assemblyName = t.Assembly.GetName().Name
    End Sub

    Friend Shared Function GetAssembly(ByVal name As String) As [Assembly]
        Try
            Return [Assembly].Load(name)
        Catch
            Return Nothing
        End Try
    End Function

    Private Sub New()
    End Sub

    <SqlFunction(FillRowMethodName:="FillAssemblyRow", Name:="GetLoadedAssemblies", _
        TableDefinition:="FullName nvarchar(256)")> _
    Public Shared Function GetLoadedAssemblies() As IEnumerable
        Dim e As IEnumerable = AppDomain.CurrentDomain.GetAssemblies()
        'Dim schemas() As Microsoft.SqlServer.Server.SqlMetaData = _
        '    {New Microsoft.SqlServer.Server.SqlMetaData("FullName", _
        '    SqlDbType.NVarChar, 256)}

        Return e
    End Function
    Public Shared Sub FillAssemblyRow(ByVal row As Object, <Out()> ByRef fullName As String)
        If row Is Nothing Then Throw New ArgumentNullException("row")
        fullName = CType(row, [Assembly]).FullName
    End Sub
End Class
<Microsoft.SqlServer.Server.SqlUserDefinedTypeAttribute(Microsoft.SqlServer.Server.Format.Native), Serializable()> _
Public Structure SimpleUdt
    Implements INullable
#Region "udt contract"

    Public Overrides Function ToString() As String
        Return Value.ToString()
    End Function

    Public ReadOnly Property IsNull() As Boolean Implements INullable.IsNull
        Get
            Return Me.Value.IsNull
        End Get
    End Property

    Public Shared ReadOnly Property Null() As SimpleUdt
        Get
            Dim h As New SimpleUdt()

            Return h
        End Get
    End Property

    Public Shared Function Parse(ByVal sqlString As SqlString) As SimpleUdt
        If sqlString.IsNull Then
            Return Null
        End If

        Dim simpleUdt As New SimpleUdt()

        simpleUdt.Value = New SqlInt32(Integer.Parse(sqlString.Value, _
            System.Globalization.CultureInfo.InvariantCulture))

        Return simpleUdt
    End Function
#End Region

#Region "implementation"
    Private privValue As SqlInt32

    Private _examplePublicField As SqlInt32

    Public Property ExamplePublicField() As SqlInt32
        Get
            Return Me._examplePublicField
        End Get
        Set(ByVal value As SqlInt32)
            Me._examplePublicField = value
        End Set
    End Property

    Public Property Value() As SqlInt32
        Get
            Return Me.privValue
        End Get
        Set(ByVal value As SqlInt32)
            Me.privValue = value
        End Set
    End Property

    <Microsoft.SqlServer.Server.SqlMethod(IsDeterministic:=True)> _
    Public Function ReturnValue() As SqlInt32
        Return Me.privValue
    End Function
#End Region
End Structure
Public NotInheritable Class UdtServices
#Region "udt fields"

    ''' <summary>
    ''' Get the fields in the UDT callable from tsql, as a table
    ''' </summary>
    ''' <param name="udtName"></param>
    ''' <returns></returns>
    <Microsoft.SqlServer.Server.SqlFunction(FillRowMethodName:="FillFieldRow", Name:="GetFields", TableDefinition:="Name nvarchar(128), Type nvarchar(128), RoutineProperties nvarchar(128)")> _
    Public Shared Function GetUdtFields(ByVal udtName As String) As IEnumerable
        Dim fields As ArrayList = GetSqlFields(GetUdt(udtName))

        Return fields
    End Function
    Public Shared Sub FillFieldRow(ByVal row As Object, ByRef [name] As String, ByRef type As String)
        Dim fi As FieldInfo = CType(row, FieldInfo)

        [name] = fi.Name
        type = fi.FieldType.Name
    End Sub


#End Region

#Region "udt properties"

    ''' <summary>
    ''' Get the properties defined in a particular UDT
    ''' </summary>
    ''' <param name="udtName"></param>
    ''' <returns></returns>
    <Microsoft.SqlServer.Server.SqlFunction(FillRowMethodName:="FillPropertyRow", Name:="GetProperties", TableDefinition:="Name nvarchar(128), Type nvarchar(128), RoutineProperties nvarchar(128)")> _
    Public Shared Function GetUdtProperties(ByVal udtName As String) As IEnumerable
        Dim properties As ArrayList = GetSqlProperties(GetUdt(udtName))

        Return properties
    End Function

    ''' <summary>
    ''' Called by SQL Server to populate a row of the results of the TVF.  
    ''' </summary>
    ''' <param name="row"></param>
    ''' <param name="name"></param>
    ''' <param name="type"></param>
    ''' <param name="routineProperties"></param>
    ''' <remarks></remarks>
    Public Shared Sub FillPropertyRow(ByVal row As Object, ByRef name As String, ByRef type As String, ByRef routineProperties As String)
        Dim pi As PropertyInfo = CType(row, PropertyInfo)

        name = pi.Name
        type = pi.PropertyType.Name

        Dim methInfo As MethodInfo = pi.GetGetMethod()
        Dim attrs As Object() = methInfo.GetCustomAttributes( _
            GetType(Microsoft.SqlServer.Server.SqlMethodAttribute), True)

        If Not (attrs Is Nothing) AndAlso attrs.Length = 1 Then
            Dim attr As Microsoft.SqlServer.Server.SqlMethodAttribute _
                = CType(attrs(0), Microsoft.SqlServer.Server.SqlMethodAttribute)

            routineProperties = GetRoutineProperties(attr)
        End If
    End Sub

#End Region

#Region "udt methods"

    ''' <summary>
    ''' Get the methods on the UDT callable from tsql, as a table
    ''' </summary>
    ''' <param name="udtName"></param>
    ''' <returns></returns>
    <Microsoft.SqlServer.Server.SqlFunction(FillRowMethodName:="FillMethodRow", Name:="GetMethods", TableDefinition:="Name nvarchar(128), Parameters nvarchar(4000), Type nvarchar(128), RoutineProperties nvarchar(128)")> _
    Public Shared Function GetUdtMethods(ByVal udtName As String) As IEnumerable
        Dim methods As ArrayList = GetSqlMethods(GetUdt(udtName))

        Return methods
    End Function

    ''' <summary>
    ''' Called by SQL Server to populate a row being returned by the TVF.  Breaks apart the 
    ''' MethodInfo object into the data which will populate each column of the row being returned.
    ''' </summary>
    ''' <param name="row"></param>
    ''' <param name="name"></param>
    ''' <param name="parameters"></param>
    ''' <param name="type"></param>
    ''' <param name="routineProperties"></param>
    ''' <remarks></remarks>
    Public Shared Sub FillMethodRow(ByVal row As Object, ByRef name As String, ByRef parameters As String, _
        ByRef type As String, ByRef routineProperties As String)
        Dim methInfo As MethodInfo = CType(row, MethodInfo)

        name = methInfo.Name

        Dim sb As New StringBuilder("(")
        Dim first As Boolean = True

        Dim pi As ParameterInfo
        For Each pi In methInfo.GetParameters()
            If first Then
                first = False
            Else
                sb.Append(", ")
            End If

            sb.Append(pi.Name).Append(" ").Append(pi.ParameterType.Name)
        Next pi

        sb.Append(")")
        parameters = sb.ToString()
        type = methInfo.ReturnType.Name

        Dim attrs As Object() = methInfo.GetCustomAttributes( _
            GetType(Microsoft.SqlServer.Server.SqlMethodAttribute), True)

        If Not (attrs Is Nothing) AndAlso attrs.Length = 1 Then
            Dim attr As Microsoft.SqlServer.Server.SqlMethodAttribute _
                = CType(attrs(0), Microsoft.SqlServer.Server.SqlMethodAttribute)

            routineProperties = GetRoutineProperties(attr)
        End If
    End Sub

#End Region

#Region "internal utility functions"
    Private Sub New()
    End Sub

    ''' <summary>
    ''' Utility function to get the string representation of
    ''' routine properties on a type
    ''' </summary>
    ''' <param name="attr"></param>
    ''' <returns></returns>
    Private Shared Function GetRoutineProperties(ByVal attr As Microsoft.SqlServer.Server.SqlMethodAttribute) As String
        Dim sb As New StringBuilder()

        If attr.OnNullCall Then
            sb.Append("on_null_call ")
        End If

        If attr.IsMutator Then
            sb.Append("mutator ")
        End If

        If attr.IsDeterministic Then
            sb.Append("deterministic ")
        End If

        If attr.IsPrecise Then
            sb.Append("precise ")
        End If

        If attr.DataAccess <> Microsoft.SqlServer.Server.DataAccessKind.None Then
            sb.Append("data_access " & [Enum].GetName( _
                GetType(Microsoft.SqlServer.Server.DataAccessKind), attr.DataAccess))
        End If

        Return sb.ToString()
    End Function

    ''' <summary>
    ''' Is this a valid parameter type that can be accessible from tsql
    ''' </summary>
    ''' <param name="t"></param>
    ''' <returns></returns>
    Private Shared Function IsSqlParameterType(ByVal t As Type) As Boolean
        If validParameterTypes.ContainsKey(t) Then
            Return True
        End If

        If t.FullName.StartsWith("System.Data.SqlTypes") Then
            Return True
        End If

        If t.GetCustomAttributes( _
            GetType(Microsoft.SqlServer.Server.SqlUserDefinedTypeAttribute), _
            True).Length = 1 Then
            Return True
        End If

        Return False
    End Function

    ''' <summary>
    ''' Is the field type valid?
    ''' </summary>
    ''' <param name="f"></param>
    ''' <param name="declaringType"></param>
    ''' <returns></returns>
    Private Shared Function IsSqlField(ByVal f As FieldInfo, ByVal declaringType As Type) As Boolean
        If Not f.DeclaringType Is declaringType Then
            Return False
        End If

        Return IsSqlParameterType(f.FieldType)
    End Function

    ''' <summary>
    ''' Is the property valid to be called from tsql?
    ''' </summary>
    ''' <param name="f"></param>
    ''' <param name="declaringType"></param>
    ''' <returns></returns>
    Private Shared Function IsSqlProperty(ByVal f As PropertyInfo, ByVal declaringType As Type) As Boolean
        If Not f.DeclaringType Is declaringType Then
            Return False
        End If

        Return IsSqlParameterType(f.PropertyType)
    End Function

    ''' <summary>
    ''' Is the method valid to be called from tsql?
    ''' </summary>
    ''' <param name="m"></param>
    ''' <param name="declaringType"></param>
    ''' <returns></returns>
    Private Shared Function IsSqlMethod(ByVal m As MethodInfo, ByVal declaringType As Type) As Boolean
        If Not m.DeclaringType Is declaringType Then
            Return False
        End If

        Dim info As ParameterInfo
        For Each info In m.GetParameters()
            If Not IsSqlParameterType(info.ParameterType) Then
                Return False
            End If
        Next info

        Return IsSqlParameterType(m.ReturnType)
    End Function

    ''' <summary>
    ''' Get the udt specified by the clr type name.
    ''' </summary>
    ''' <param name="udtName"></param>
    ''' <returns></returns>
    Private Shared Function GetUdt(ByVal udtName As String) As Type
        Return Type.GetType(udtName, True)
    End Function

    ''' <summary>
    ''' Get the methods on a type
    ''' </summary>
    ''' <param name="t"></param>
    ''' <returns></returns>
    Private Shared Function GetSqlMethods(ByVal t As Type) As ArrayList
        Dim methods As MethodInfo() = t.GetMethods(BindingFlags.Instance Or BindingFlags.Public Or BindingFlags.DeclaredOnly)
        Dim temp As New ArrayList()

        Dim info As MethodInfo
        For Each info In methods
            If IsSqlMethod(info, t) Then
                temp.Add(info)
            End If
        Next info

        Return temp
    End Function

    ''' <summary>
    ''' get the properties on a type
    ''' </summary>
    ''' <param name="t"></param>
    ''' <returns></returns>
    Private Shared Function GetSqlProperties(ByVal t As Type) As ArrayList
        Dim props As PropertyInfo() = t.GetProperties(BindingFlags.Instance Or BindingFlags.Public Or BindingFlags.DeclaredOnly)
        Dim temp As New ArrayList()

        Dim info As PropertyInfo
        For Each info In props
            If IsSqlProperty(info, t) Then
                temp.Add(info)
            End If
        Next info

        Return temp
    End Function

    ''' <summary>
    ''' get the fields on a type
    ''' </summary>
    ''' <param name="t"></param>
    ''' <returns></returns>
    Private Shared Function GetSqlFields(ByVal t As Type) As ArrayList
        Dim fields As FieldInfo() = t.GetFields(BindingFlags.Instance Or BindingFlags.Public Or BindingFlags.DeclaredOnly)
        Dim temp As New ArrayList()

        Dim info As FieldInfo
        For Each info In fields
            If IsSqlField(info, t) Then
                temp.Add(info)
            End If
        Next info

        Return temp
    End Function

    ''' <summary>
    ''' readonly static used to cache frequently used information
    ''' </summary>
    Private Shared ReadOnly validParameterTypes As Hashtable = GetValidParameterTypes()

    ''' <summary>
    ''' initialize the cached mapping of valid parameter types
    ''' </summary>
    Private Shared Function GetValidParameterTypes() As Hashtable
        Dim validTypes As New Hashtable()

        validTypes(GetType(Boolean)) = True
        validTypes(GetType(Byte)) = True
        validTypes(GetType(Short)) = True
        validTypes(GetType(Char)) = True
        validTypes(GetType(Integer)) = True
        validTypes(GetType(Single)) = True
        validTypes(GetType(Long)) = True
        validTypes(GetType(Double)) = True
        validTypes(GetType(String)) = True
        validTypes(GetType(Guid)) = True

        Return validTypes
    End Function
#End Region

#Region "public utility functions"

    <Microsoft.SqlServer.Server.SqlFunction(DataAccess:=Microsoft.SqlServer.Server.DataAccessKind.Read)> _
    Public Shared Function GetFullAssemblyName(ByVal sqlName As String) As String
        Using conn As New SqlConnection("context connection=true")
            Dim cmd As SqlCommand = conn.CreateCommand()
            cmd.CommandText = "SELECT @sqlName, " _
                & "assemblyproperty(@sqlName, 'VersionMajor'), " _
                & "assemblyproperty(@sqlName, 'VersionMinor'), " _
                & "assemblyproperty(@sqlName, 'VersionBuild'), " _
                & "assemblyproperty(@sqlName, 'VersionRevision'), " _
                & "assemblyproperty(@sqlName, 'CultureInfo'), " _
                & "assemblyproperty(@sqlName, 'PublicKey'), " _
                & "assemblyproperty(@sqlName, 'Architecture');"

            cmd.Parameters.AddWithValue("@sqlName", sqlName)
            conn.Open()
            Dim rdr As SqlDataReader = cmd.ExecuteReader()
            If Not rdr.Read() Then
                Throw New ArgumentException( _
                    String.Format(System.Globalization.CultureInfo.InvariantCulture, _
                    "Assembly {0} does not exist.", sqlName))
            End If

            Dim culture As SqlString
            Dim publicKeyToken As SqlBinary

            If (rdr.IsDBNull(5)) Then
                culture = SqlString.Null
            Else
                culture = rdr.GetSqlString(5)
            End If

            If (rdr.IsDBNull(6)) Then
                publicKeyToken = SqlBinary.Null
            Else
                publicKeyToken = rdr.GetSqlBinary(6)
            End If

            Return GetAssemblyName(rdr.GetString(0), rdr.GetInt32(1), rdr.GetInt32(2), _
                rdr.GetInt32(3), rdr.GetInt32(4), culture, publicKeyToken)
        End Using
    End Function

    ''' <summary>
    ''' Helper function to return the assembly name from 
    ''' its components stored in sql metadata.
    ''' </summary>
    ''' <param name="friendlyName"></param>
    ''' <param name="majorVersion"></param>
    ''' <param name="minorVersion"></param>
    ''' <param name="build"></param>
    ''' <param name="revision"></param>
    ''' <param name="culture"></param>
    ''' <param name="publicKeyToken"></param>
    ''' <returns></returns>
    Private Shared Function GetAssemblyName(ByVal friendlyName As String, ByVal majorVersion As Integer, ByVal minorVersion As Integer, ByVal build As Integer, ByVal revision As Integer, ByVal culture As SqlString, ByVal publicKeyToken As SqlBinary) As String
        Dim sb As New StringBuilder()
        sb.Append(friendlyName).Append(","c)
        sb.Append("Version=")
        sb.Append(majorVersion).Append("."c)
        sb.Append(minorVersion).Append("."c)
        sb.Append(build).Append("."c)
        sb.Append(revision).Append(","c)
        sb.Append("Culture=")
        If (culture.IsNull) Then
            sb.Append("neutral")
        Else
            sb.Append(culture.Value)
        End If

        sb.Append(","c)
        sb.Append("PublicKeyToken=")
        If publicKeyToken.IsNull Then
            sb.Append("null")
        Else
            Dim b As Byte
            For Each b In publicKeyToken.Value
                sb.Append(b.ToString("X2", CultureInfo.InvariantCulture))
            Next b
        End If

        Return sb.ToString()
    End Function

    Private Shared Function ToHexString(ByVal value() As Byte) As String
        If value Is Nothing Then
            Return Nothing
        End If

        Dim sb As New StringBuilder()
        Dim b As Byte

        For Each b In value
            sb.Append(b.ToString("X2", CultureInfo.InvariantCulture))
        Next b

        Return sb.ToString()
    End Function
#End Region
End Class

Di seguito è illustrato lo script di installazione Transact-SQL (Install.sql) che consente la distribuzione dell'assembly e la creazione del tipo definito dall'utente nel database.

USE AdventureWorks
GO
IF EXISTS (SELECT * FROM sys.types WHERE name = N'ComplexNumber')
DROP TYPE ComplexNumber;
GO

IF EXISTS (SELECT * FROM sys.assemblies WHERE name = N'ComplexNumber') 
DROP ASSEMBLY ComplexNumber;
GO

DECLARE @SamplesPath nvarchar(1024)
-- You may need to modify the value of the this variable if you have installed 
-- the sample someplace other than the default location.
SET @SamplesPath = 'C:\MySample\'

CREATE ASSEMBLY ComplexNumber 
FROM @SamplesPath + 'ComplexNumber.dll'
WITH permission_set=Safe;
GO

CREATE TYPE ComplexNumber
EXTERNAL NAME [ComplexNumber].[ComplexNumber];
GO

Di seguito è illustrato lo script test.sql che consente di testare l'esempio eseguendo il tipo.

USE AdventureWorks
GO

-- Get the full CLR name for UDTUtilities
SELECT dbo.GetFullAssemblyName(N'UDTUtilities');
GO

-- Get all the types in this dll
SELECT * FROM dbo.GetTypes(dbo.GetFullAssemblyName(N'UDTUtilities')); 
GO

-- Get the full CLR name for SimpleUdt
SELECT dbo.GetClrTypeName('SimpleUdt');
GO

-- Get the methods on the SimpleUdt type
SELECT * FROM dbo.GetMethods(dbo.GetClrTypeName('SimpleUdt'));
GO

-- More complex query to dump all the methods for all the types in the system
SELECT 
    st.name AS TypeName, 
    methods.Name AS MethodName, 
    methods.Parameters, 
    methods.Type, 
    methods.RoutineProperties 
FROM sys.assembly_types st 
    CROSS APPLY dbo.GetMethods(dbo.GetClrTypeName(st.name)) methods
GO

Il codice Transact-SQL seguente consente di rimuovere l'assembly e il tipo dal database.

USE AdventureWorks
GO

IF EXISTS (SELECT * FROM sys.types WHERE name = N'ComplexNumber')
DROP TYPE ComplexNumber;
GO

IF EXISTS (SELECT * FROM sys.assemblies WHERE name = N'ComplexNumber') 
DROP ASSEMBLY ComplexNumber;
GO

Vedere anche

Concetti

Scenari di utilizzo ed esempi per l'integrazione con CLR (Common Language Runtime)

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