Type de données défini par l'utilisateur (UDT) pour les chaînes UTF8

Article
05/07/2013

L'exemple UTF8String pour SQL Server montre l'implémentation d'un type de données défini par l'utilisateur. Cet exemple montre comment mettre en œuvre un type de données UTF8 défini par l'utilisateur qui étend le système de types de la base de données pour assurer le stockage des valeurs encodées en UTF8. Ce type implémente également le code permettant de convertir les chaînes Unicode en UTF8 et vice versa.

Configuration préalable requise

Pour créer et exécuter ce projet, les logiciels suivants doivent être installés :

SQL Server ou SQL Server Express. Vous pouvez vous procurer gratuitement SQL Server Express à partir du site Web SQL Server Express Documentation and Samples (en anglais)
Base de données AdventureWorks qui est disponible sur le site Web du Centre pour les développeurs SQL Server
Le Kit de développement logiciel .NET Framework SDK 2.0 ou version ultérieure, ou Microsoft Visual Studio 2005 ou version ultérieure. Vous pouvez vous procurer gratuitement le Kit de développement logiciel .NET Framework SDK.
De plus, les conditions suivantes doivent être réunies :
L'intégration du CLR doit être activée sur l'instance SQL Server que vous utilisez.
Pour activer l'intégration du CLR, effectuez les étapes suivantes :

Activation de l'intégration du CLR
- Exécutez les commandes Transact-SQL suivantes :
sp_configure 'clr enabled', 1

GO

RECONFIGURE

GO

[!REMARQUE]

Pour activer l'intégration du CLR, vous devez disposer de l'autorisation de niveau serveur ALTER SETTINGS qui est attribuée implicitement aux membres des rôles serveur fixes sysadmin et serveradmin.
La base de données AdventureWorks doit être installée sur l'instance SQL Server que vous utilisez.
Si vous n'êtes pas administrateur de l'instance SQL Server utilisée, vous devez demander à un administrateur de vous accorder l'autorisation CreateAssembly pour terminer l'installation.

Génération de l'exemple

Créez et exécutez l'exemple à l'aide des instructions suivantes :

Ouvrez une invite de commandes Visual Studio ou .NET Framework.
Si nécessaire, créez un répertoire pour votre exemple. Pour cet exemple, nous utiliserons C:\MySample.
Dans c:\MySample, créez Utf8String.vb (pour l'exemple Visual Basic) ou Utf8String.cs (pour l'exemple C#) et copiez l'exemple de code Visual Basic ou C# approprié (ci-dessous) dans le fichier.
Compilez l'exemple de code à partir de l'invite de ligne de commande en exécutant l'un des éléments suivants, selon le langage choisi.
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 Utf8String.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 Utf8String.cs
Copiez le code d'installation Transact-SQL dans un fichier et enregistrez-le sous Install.sql dans le répertoire d'exemple.
Si l'exemple est installé dans un répertoire autre que C:\MySample\, modifiez le fichier Install.sql comme indiqué pour pointer sur cet emplacement.
Déployez l'assembly et la procédure stockée en exécutant
- sqlcmd -E -I -i install.sql
Copiez le script de la commande de test Transact-SQL dans un fichier et enregistrez-le sous test.sql dans le répertoire d'exemple.
Exécutez le script de test avec la commande suivante
- sqlcmd -E -I -i test.sql
Copiez le script de nettoyage Transact-SQL dans un fichier et enregistrez-le sous cleanup.sql dans le répertoire d'exemple.
Exécutez le script avec la commande suivante
- sqlcmd -E -I -i cleanup.sql

Exemple de code

Voici les listes de code pour cet exemple.

using System;
using System.Xml;
using System.Data.Sql;
using System.Data.SqlTypes;
using System.Globalization;
using Microsoft.SqlServer.Server;
using System.Runtime.CompilerServices;
using System.Reflection;

    [Serializable]
    [Microsoft.SqlServer.Server.SqlUserDefinedType(Microsoft.SqlServer.Server.Format.UserDefined, IsByteOrdered = true, MaxByteSize = 8000)]
    public class Utf8String : INullable, IComparable, Microsoft.SqlServer.Server.IBinarySerialize
    {
        #region conversion to/from Unicode strings
        /// <summary>
        /// Parse the given string and return a utf8 representation for it.
        /// </summary>
        /// <param name="sqlString"></param>
        /// <returns></returns>
        public static Utf8String Parse(SqlString sqlString)
        {
            if (sqlString.IsNull)
                return Utf8String.Null;

            return new Utf8String(sqlString.Value);
        }

        /// <summary>
        /// Get/Set the utf8 bytes for this string.
        /// </summary>
        public SqlBinary Utf8Bytes
        {
            get
            {
                if (this.IsNull)
                    return SqlBinary.Null;

                if (this.m_Bytes != null)
                    return this.m_Bytes;

                if (this.m_String != null)
                {
                    this.m_Bytes = System.Text.Encoding.UTF8.GetBytes(this.m_String);
                    return new SqlBinary(this.m_Bytes);
                }

                throw new NotSupportedException("cannot return bytes for empty instance");
            }
            set
            {
                if (value.IsNull)
                {
                    this.m_Bytes = null;
                    this.m_String = null;
                }
                else
                {
                    this.m_Bytes = value.Value;
                    this.m_String = null;
                }
            }
        }

        /// <summary>
        /// Return a unicode string for this type.
        /// </summary>
        [Microsoft.SqlServer.Server.SqlMethod(IsDeterministic = true, IsPrecise = true, DataAccess = Microsoft.SqlServer.Server.DataAccessKind.None, SystemDataAccess = Microsoft.SqlServer.Server.SystemDataAccessKind.None)]
        public override string ToString()
        {
            if (this.IsNull)
                return null;

            if (this.m_String != null)
                return this.m_String;

            if (this.m_Bytes != null)
            {
                this.m_String = System.Text.Encoding.UTF8.GetString(this.m_Bytes);
                return this.m_String;
            }

            throw new NotSupportedException("don't know how to return string from empty instance");
        }

        /// <summary>
        /// Return a SqlStr
        /// </summary>
        public SqlString ToSqlString()
        {
            if (this.IsNull)
                return SqlString.Null;

            return new SqlString(this.ToString());
        }


        private SqlString GetSortKeyUsingCultureInternal(CultureInfo culture, bool ignoreCase,
            bool ignoreNonSpace, bool ignoreWidth)
        {
            if (this.IsNull)
                return SqlString.Null;
            
            SqlCompareOptions compareOptions = SqlCompareOptions.None;
            if (ignoreCase) 
                compareOptions = compareOptions | SqlCompareOptions.IgnoreCase;

            if (ignoreNonSpace) 
                compareOptions = compareOptions | SqlCompareOptions.IgnoreNonSpace;

            if (ignoreWidth) 
                compareOptions = compareOptions | SqlCompareOptions.IgnoreWidth;

            return new SqlString(this.ToString(), culture.LCID, compareOptions);
        }

        [Microsoft.SqlServer.Server.SqlMethod(IsDeterministic = true, IsPrecise = true)]
        public SqlString GetSortKeyUsingCulture(string cultureName, bool ignoreCase,
            bool ignoreNonSpace, bool ignoreWidth)
        {
            CultureInfo culture = CultureInfo.CreateSpecificCulture(cultureName);
            if (culture == null)
                throw new ArgumentException(string.Format(
                    CultureInfo.InvariantCulture,
                    "Culture {0} not recognized.", cultureName));

            return this.GetSortKeyUsingCultureInternal(culture, ignoreCase, 
                ignoreNonSpace, ignoreWidth);
        }

        [Microsoft.SqlServer.Server.SqlMethod(IsDeterministic = false)]
        public SqlString GetSortKey(bool ignoreCase, bool ignoreNonSpace, bool ignoreWidth)
        {
            return this.GetSortKeyUsingCultureInternal(CultureInfo.CurrentCulture,
                ignoreCase, ignoreNonSpace, ignoreWidth);
        }

        #endregion

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

        public static bool operator ==(Utf8String utf8String, Utf8String other)
        {
            if (utf8String.IsNull) throw new ArgumentException(string.Empty);
            return utf8String.Equals(other);
        }

        public static bool operator !=(Utf8String utf8String, Utf8String other)
        {
            return !(utf8String == other);
        }

        public static bool operator <(Utf8String utf8String, Utf8String other)
        {
            if (utf8String == null) throw new ArgumentException(string.Empty);
            return (utf8String.CompareTo(other) < 0);
        }

        public static bool operator >(Utf8String utf8String, Utf8String other)
        {
            if (utf8String == null) throw new ArgumentException(string.Empty);
            return (utf8String.CompareTo(other) > 0);
        }  

        private int CompareUsingCultureInternal(Utf8String other, CultureInfo culture, bool ignoreCase,
            bool ignoreNonSpace, bool ignoreWidth)
        {
            // By definition
            if (other == null) 
                return 1;

            if (this.IsNull)
                if (other.IsNull)
                    return 0;
                else
                    return -1;

            if (other.IsNull) 
                return 1;

            return this.GetSortKeyUsingCultureInternal(culture, ignoreCase, ignoreNonSpace,
                ignoreWidth).CompareTo(other.GetSortKeyUsingCultureInternal(culture, ignoreCase,
                ignoreNonSpace, ignoreWidth));
        }

        public int CompareUsingCulture(Utf8String other, string cultureName, bool ignoreCase,
            bool ignoreNonSpace, bool ignoreWidth)
        {
            CultureInfo culture = CultureInfo.CreateSpecificCulture(cultureName);
            if (culture == null)
                throw new ArgumentException(string.Format(
                    CultureInfo.InvariantCulture, 
                    "Culture {0} not recognized.", cultureName));

            return this.CompareUsingCultureInternal(other, culture, ignoreCase,
                ignoreNonSpace, ignoreWidth);
        }

        public int Compare(Utf8String other, bool ignoreCase,
            bool ignoreNonSpace, bool ignoreWidth)
        {
            return this.CompareUsingCultureInternal(other, CultureInfo.CurrentCulture, ignoreCase,
                ignoreNonSpace, ignoreWidth);
        }

        public override int GetHashCode()
        {
            if (this.IsNull)
                return 0;

            return this.ToString().GetHashCode();
        }

        public int CompareTo(object obj)
        {
            if (obj == null)
                return 1; //by definition

            Utf8String s = obj as Utf8String;

            if (s == null)
                throw new ArgumentException("the argument to compare is not a Utf8String");

            if (this.IsNull)
            {
                if (s.IsNull)
                    return 0;

                return -1;
            }

            if (s.IsNull)
                return 1;

            return this.ToString().CompareTo(s.ToString());
        }

        #endregion

        #region private state and constructors
        private string m_String;

        private byte[] m_Bytes;

        public Utf8String(string value)
        {
            this.m_String = value;
        }

        public Utf8String(byte[] bytes)
        {
            this.m_Bytes = bytes;
        }
        #endregion

        #region UserDefinedType boilerplate code

        public bool IsNull
        {
            get
            {
                return this.m_String == null && this.m_Bytes == null;
            }
        }

        public static Utf8String Null
        {
            get
            {
                Utf8String str = new Utf8String((string)null);

                return str;
            }
        }

        public Utf8String()
        {
        }
        #endregion

        #region IBinarySerialize Members
        public void Write(System.IO.BinaryWriter w)
        {
            if (w == null) throw new ArgumentException(string.Empty);
            byte header = (byte)(this.IsNull ? 1 : 0);

            w.Write(header);
            if (header == 1)
                return;

            byte[] bytes = this.Utf8Bytes.Value;

            w.Write(bytes.Length);
            w.Write(bytes);
        }

        public void Read(System.IO.BinaryReader r)
        {
            if (r == null) throw new ArgumentException(string.Empty);
            byte header = r.ReadByte();

            if ((header & 1) > 0)
            {
                this.m_Bytes = null;
                return;
            }

            int length = r.ReadInt32();

            this.m_Bytes = r.ReadBytes(length);
        }
        #endregion
    }

Visual Basic

Imports Microsoft.SqlServer.Server
Imports Microsoft.VisualBasic
Imports System
Imports System.Collections
Imports System.Data
Imports System.Data.SqlTypes
Imports System.Diagnostics
Imports System.Globalization
<Serializable(), Microsoft.SqlServer.Server.SqlUserDefinedType(Microsoft.SqlServer.Server.Format.UserDefined, IsByteOrdered:=True, MaxByteSize:=8000), CLSCompliant(False)> _
Public Class Utf8String
    Implements INullable, IComparable, Microsoft.SqlServer.Server.IBinarySerialize
#Region "Conversion to/from Unicode strings"
    ''' <summary>
    ''' Parse the given string and return a utf8 representation for it.
    ''' </summary>
    ''' <param name="sqlString"></param>
    ''' <returns></returns>
    Public Shared Function Parse(ByVal sqlString As SqlString) As Utf8String
        If sqlString.IsNull Then
            Return Utf8String.Null
        End If

        Return New Utf8String(sqlString.Value)
    End Function

    ''' <summary>
    ''' Get/Set the utf8 bytes for this string.
    ''' </summary>
    Public Property Utf8Bytes() As SqlBinary
        Get
            If Me.IsNull Then
                Return SqlBinary.Null
            End If

            If Not (Me.privBytes Is Nothing) Then
                Return Me.privBytes
            End If

            If Not (Me.privString Is Nothing) Then
                Me.privBytes = System.Text.Encoding.UTF8.GetBytes(Me.privString)
                Return New SqlBinary(Me.privBytes)
            End If

            Throw New NotSupportedException("Cannot return bytes for empty instance")
        End Get
        Set(ByVal value As SqlBinary)
            If value.IsNull Then
                Me.privBytes = Nothing
                Me.privString = Nothing
            Else
                Me.privBytes = value.Value
                Me.privString = Nothing
            End If
        End Set
    End Property

    ''' <summary>
    ''' Return a unicode string for this type.
    ''' </summary>
    <Microsoft.SqlServer.Server.SqlMethod(IsDeterministic:=True, IsPrecise:=True, DataAccess:=Microsoft.SqlServer.Server.DataAccessKind.None, SystemDataAccess:=Microsoft.SqlServer.Server.SystemDataAccessKind.None)> _
    Public Overrides Function ToString() As String
        If Me.IsNull Then
            Return Nothing
        End If

        If Not (Me.privString Is Nothing) Then
            Return Me.privString
        End If

        If Not (Me.privBytes Is Nothing) Then
            Me.privString = System.Text.Encoding.UTF8.GetString(Me.privBytes)
            Return Me.privString
        End If

        Throw New NotSupportedException("dont know how to return string from empty instance")
    End Function

    ''' <summary>
    ''' Return a SqlStr
    ''' </summary>
    Public Function ToSqlString() As SqlString
        If Me.IsNull Then
            Return SqlString.Null
        End If

        Return New SqlString(Me.ToString())
    End Function

    Private Function GetSortKeyUsingCultureInternal(ByVal culture As CultureInfo, ByVal ignoreCase As Boolean, _
    ByVal ignoreNonSpace As Boolean, ByVal ignoreWidth As Boolean) As SqlString
        If Me.IsNull Then
            Return SqlString.Null
        End If
        Dim compareOptions As SqlCompareOptions = SqlCompareOptions.None
        If ignoreCase Then
            compareOptions = compareOptions Or SqlCompareOptions.IgnoreCase
        End If
        If ignoreNonSpace Then
            compareOptions = compareOptions Or SqlCompareOptions.IgnoreNonSpace
        End If
        If ignoreWidth Then
            compareOptions = compareOptions Or SqlCompareOptions.IgnoreWidth
        End If
        Return New SqlString(Me.ToString(), culture.LCID, compareOptions)
    End Function

    <Microsoft.SqlServer.Server.SqlMethod(IsDeterministic:=True, IsPrecise:=True)> _
    Public Function GetSortKeyUsingCulture(ByVal cultureName As String, ByVal ignoreCase As Boolean, _
    ByVal ignoreNonSpace As Boolean, ByVal ignoreWidth As Boolean) As SqlString
        Dim culture As CultureInfo = CultureInfo.CreateSpecificCulture(cultureName)
        If culture Is Nothing Then
            Throw New ArgumentException(String.Format(CultureInfo.InvariantCulture, _
            "Culture {0} not recognized.", cultureName))
        End If

        Return Me.GetSortKeyUsingCultureInternal(culture, ignoreCase, ignoreNonSpace, ignoreWidth)
    End Function

    <Microsoft.SqlServer.Server.SqlMethod(IsDeterministic:=True, IsPrecise:=True)> _
    Public Function GetSortKey(ByVal ignoreCase As Boolean, ByVal ignoreNonSpace As Boolean, _
    ByVal ignoreWidth As Boolean) As SqlString
        Return Me.GetSortKeyUsingCultureInternal(CultureInfo.CurrentCulture, ignoreCase, ignoreNonSpace, ignoreWidth)
    End Function

#End Region

#Region "Comparison operators"
    Public Overrides Function Equals(ByVal obj As Object) As Boolean
        Return Me.CompareTo(obj) = 0
    End Function

    Public Shared Operator =(ByVal utf8StringValue As Utf8String, ByVal other As Utf8String) As Boolean
        If utf8StringValue Is Nothing Then
            Throw New ArgumentException(String.Empty)
        End If
        Return utf8StringValue.Equals(other)
    End Operator

    Public Shared Operator <>(ByVal utf8StringValue As Utf8String, ByVal other As Utf8String) As Boolean
        Return Not (utf8StringValue = other)
    End Operator

    Public Shared Operator <(ByVal utf8StringValue As Utf8String, ByVal other As Utf8String) As Boolean
        If utf8StringValue Is Nothing Then
            Throw New ArgumentException(String.Empty)
        End If
        Return (utf8StringValue.CompareTo(other) < 0)
    End Operator

    Public Shared Operator >(ByVal utf8StringValue As Utf8String, ByVal other As Utf8String) As Boolean
        If utf8StringValue Is Nothing Then
            Throw New ArgumentException(String.Empty)
        End If
        Return (utf8StringValue.CompareTo(other) > 0)
    End Operator

    Private Function CompareUsingCultureInternal(ByVal other As Utf8String, ByVal culture As CultureInfo, _
        ByVal ignoreCase As Boolean, ByVal ignoreNonSpace As Boolean, _
        ByVal ignoreWidth As Boolean) As Integer
        'By definition
        If other Is Nothing Then
            Return 1
        End If

        If Me.IsNull Then
            If other.IsNull Then
                Return 0
            Else
                Return -1
            End If
        End If

        If other.IsNull Then
            Return 1
        End If

        Return Me.GetSortKeyUsingCultureInternal(culture, ignoreCase, ignoreNonSpace, _
        ignoreWidth).CompareTo(other.GetSortKeyUsingCultureInternal(culture, ignoreCase, _
        ignoreNonSpace, ignoreWidth))
    End Function

    Public Function CompareUsingCulture(ByVal other As Utf8String, ByVal cultureName As String, _
        ByVal ignoreCase As Boolean, ByVal ignoreNonSpace As Boolean, _
        ByVal ignoreWidth As Boolean) As Integer
        Dim culture As CultureInfo = CultureInfo.CreateSpecificCulture(cultureName)
        If culture Is Nothing Then
            Throw New ArgumentException(String.Format(CultureInfo.InvariantCulture, _
            "Culture {0} not recognized.", cultureName))
        End If

        Return Me.CompareUsingCultureInternal(other, culture, ignoreCase, _
        ignoreNonSpace, ignoreWidth)
    End Function

    Public Function Compare(ByVal other As Utf8String, ByVal ignoreCase As Boolean, ByVal ignoreNonSpace As Boolean, _
        ByVal ignoreWidth As Boolean) As Integer
        Return Me.CompareUsingCultureInternal(other, CultureInfo.CurrentCulture, ignoreCase, _
        ignoreNonSpace, ignoreWidth)
    End Function

    Public Overrides Function GetHashCode() As Integer
        If Me.IsNull Then
            Return 0
        End If

        Return Me.ToString().GetHashCode()
    End Function

    Public Function CompareTo(ByVal obj As Object) As Integer Implements IComparable.CompareTo
        If obj Is Nothing Then
            Return 1 'by definition
        End If

        Dim s As Utf8String = CType(obj, Utf8String)

        If s Is Nothing Then
            Throw New ArgumentException("the argument to compare is not a Utf8String")
        End If

        If Me.IsNull Then
            If s.IsNull Then
                Return 0
            End If
            Return -1
        End If

        If s.IsNull Then
            Return 1
        End If

        Return Me.ToString().CompareTo(s.ToString())
    End Function
#End Region

#Region "Private state and constructors"
    Private privString As String
    Private privBytes() As Byte

    Public Sub New(ByVal value As String)
        Me.privString = value
        'Me.privBytes = Nothing
    End Sub

    Public Sub New(ByVal bytes() As Byte)
        Me.privBytes = bytes
        'Me.privString = Nothing
    End Sub
#End Region

#Region "UserDefinedType boilerplate code"
    Public ReadOnly Property IsNull() As Boolean Implements INullable.IsNull
        Get
            Return Me.privString Is Nothing AndAlso Me.privBytes Is Nothing
        End Get
    End Property

    Public Shared ReadOnly Property Null() As Utf8String
        Get
            Dim str As New Utf8String(CStr(Nothing))

            Return str
        End Get
    End Property

    Public Sub New()
    End Sub
#End Region

#Region "IBinarySerialize Members"
    Public Sub Write(ByVal w As System.IO.BinaryWriter) Implements Microsoft.SqlServer.Server.IBinarySerialize.Write
        If w Is Nothing Then
            Throw New ArgumentException(String.Empty)
        End If
        Dim header As Byte
        If (Me.IsNull) Then
            header = 1
        Else
            header = 0
        End If

        w.Write(header)

        If header = 1 Then
            Return
        End If

        Dim bytes As Byte() = Me.Utf8Bytes.Value

        w.Write(bytes.Length)
        w.Write(bytes)
    End Sub

    Public Sub Read(ByVal r As System.IO.BinaryReader) Implements Microsoft.SqlServer.Server.IBinarySerialize.Read
        If r Is Nothing Then
            Throw New ArgumentException(String.Empty)
        End If
        Dim header As Byte = r.ReadByte()

        If (header And 1) > 0 Then
            Me.privBytes = Nothing
            Return
        End If

        Dim length As Integer = r.ReadInt32()

        Me.privBytes = r.ReadBytes(length)
    End Sub
#End Region
End Class

Il s'agit du script d'installation Transact-SQL (Install.sql), qui déploie l'assembly et crée l'UDT dans la base de données.

USE AdventureWorks;
GO

IF EXISTS (SELECT * FROM sys.objects WHERE ([name] = N'ResumeFullName') AND ([type] = 'FN'))
DROP FUNCTION [dbo].[ResumeFullName];
GO

IF EXISTS (SELECT * FROM sys.indexes WHERE NAME = N'IX_utf8test_ustr')
DROP INDEX utf8test.IX_utf8test_ustr;
GO

IF EXISTS (SELECT * FROM sys.tables WHERE name = N'utf8test') 
DROP TABLE [dbo].[utf8test];
GO

IF EXISTS (SELECT * FROM sys.tables WHERE name = N'ResumeNames') 
DROP TABLE [dbo].[ResumeNames];
GO

IF EXISTS (SELECT * FROM sys.types WHERE name = N'Utf8String') 
DROP TYPE [Utf8String];
GO

IF EXISTS (SELECT * FROM sys.assemblies WHERE name = N'UTF8String') 
DROP ASSEMBLY UTF8String;
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= N'C:\MySample\'

CREATE ASSEMBLY UTF8String 
FROM @SamplesPath +'UTF8String.dll';
GO

CREATE TYPE [Utf8String] 
EXTERNAL NAME [UTF8String].[Utf8String];
GO

Il s'agit de test.sql, qui teste l'exemple en exerçant le type.

USE AdventureWorks;
GO

-- simple usage of the type in variables and select statements
-- convert to string, binary, do a substring on it, get the utf8bytes
DECLARE @u Utf8String;
SET @u = CONVERT(Utf8String, 'hello world');
SELECT @u.ToString(), 
    CONVERT(varbinary(8000), @u),
    SUBSTRING(@u.ToString(), 1, 5),
    @u.Utf8Bytes;
GO

-- create a table with this type
CREATE TABLE utf8test(u Utf8String);
GO

-- populate it with some random data
SET NOCOUNT ON;
BEGIN TRAN;
DECLARE @index int, @str nvarchar(4000);
SET @index = 0;
WHILE @index < 1000
BEGIN
    SET @str = CONVERT(nvarchar(100), @index);
    INSERT INTO utf8test VALUES(CONVERT(Utf8String, @str))
    SET @index = @index + 1;
END
COMMIT TRAN;
GO

-- Find a particular UTF8 string

DECLARE @i int;
SELECT @i = COUNT(*) from utf8test 
WHERE u = CONVERT(Utf8String, '100');
SELECT @i;
go

-- Find UTF8 strings with a particular substring
DECLARE @i int;
SELECT @i = COUNT(*) from utf8test 
WHERE SUBSTRING(u.ToString(), 1, 1) = '1';
SELECT @i;
GO


-- Add a computed column over the ToString method
ALTER TABLE utf8test ADD ustr AS u.ToString() PERSISTED;
GO

-- Create an index over the computed column
CREATE INDEX IX_utf8test_ustr ON utf8test(ustr);
GO

-- Binary comparisons on Utf8Strings are not effective.  Even if we use the ToString method
-- to convert it to a string, we may want to have more control over whether case, width, or
-- attributes are relevant to the comparison.  This portion of the test creates a table of 
-- localized data pulled from the resumes stored in the AdventureWorks database,
-- and then demonstrates comparsions and sorting based on the CompareUsingCulture 
-- and GetSortKeyUsingCulture methods defined on Utf8String.


IF EXISTS (SELECT * FROM sys.objects WHERE ([name] = N'ResumeFullName') AND ([type] = 'FN'))
DROP FUNCTION [dbo].[ResumeFullName];
GO

-- Returns the complete name of the applicant from her resume.  
-- We don't just use data(/RES:Resume[1]/RES:Name) because we need spaces
-- between each part of the name.
CREATE FUNCTION ResumeFullName (@Resume xml)
RETURNS nvarchar(100)
AS
BEGIN
    RETURN CONVERT(nvarchar(100), @Resume.query(N'declare namespace RES="https://schemas.microsoft.com/sqlserver/2004/07/adventure-works/Resume"; for $b in /RES:Resume[1]/RES:Name/* return data($b)'));
END
GO

SELECT Cast(RTRIM(LTRIM(dbo.ResumeFullName(Resume))) as Utf8String) AS FullName 
INTO ResumeNames FROM HumanResources.JobCandidate;
GO

SELECT FullName.ToString() FROM ResumeNames;

DECLARE @Shai Utf8String;
SET @Shai = N'Shai  Bassli';
SELECT FullName.ToString() FROM ResumeNames 
WHERE FullName.CompareUsingCulture(@Shai, 'en-us', 1, 0, 0) = 0;
GO

ALTER TABLE ResumeNames ADD SortKey AS FullName.GetSortKeyUsingCulture('en-us', 1, 0, 0) PERSISTED;
GO

CREATE INDEX IX_ResumeNames_SortKey ON ResumeNames(SortKey);
GO

SELECT FullName.ToString() 
FROM ResumeNames
ORDER BY SortKey;

Le code Transact-SQL suivant supprime l'assembly et le type de la base de données.

USE AdventureWorks;
GO

IF EXISTS (SELECT * FROM sys.objects WHERE ([name] = N'ResumeFullName') AND ([type] = 'FN'))
DROP FUNCTION [dbo].[ResumeFullName];
GO

IF EXISTS (SELECT * FROM sys.indexes WHERE NAME = N'IX_utf8test_ustr')
DROP INDEX utf8test.IX_utf8test_ustr;
GO

IF EXISTS (SELECT * FROM sys.tables WHERE name = N'utf8test') 
DROP TABLE [dbo].[utf8test];
GO

IF EXISTS (SELECT * FROM sys.tables WHERE name = N'ResumeNames') 
DROP TABLE [dbo].[ResumeNames];
GO

IF EXISTS (SELECT * FROM sys.types WHERE name = N'Utf8String') 
DROP TYPE [Utf8String];
GO

IF EXISTS (SELECT * FROM sys.assemblies WHERE name = N'UTF8String') 
DROP ASSEMBLY UTF8String;
GO

Voir aussi

Concepts

Scénarios et exemples d'utilisation pour l'intégration du CLR (Common Language Runtime)

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