Tipo de dados de cadeia de caracteres UTF8 definido pelo usuário (UDT)

Artigo
05/07/2013

O exemplo UTF8String do SQL Server demonstra a implementação de um tipo de dados definido pelo usuário. Esse exemplo mostra a implementação de um tipo de dados UTF8 definido pelo usuário, que estende o sistema de tipos do banco de dados para fornecer armazenamento para valores UTF8 codificados. Esse tipo também implementa código para converter a cadeia de caracteres Unicode de e para UTF8.

Pré-requisitos

Para criar e executar este projeto, o software a seguir deve estar instalado:

SQL Server ou SQL Server Express. É possível obter o SQL Server Express gratuitamente no site de Documentação e exemplos do SQL Server Express
O banco de dados AdventureWorks, que está disponível no site do SQL Server Developer
.NET Framework SDK 2.0 ou posterior ou Microsoft Visual Studio 2005 ou posterior. Você pode obter o .NET Framework SDK gratuitamente.
Além disso, as seguintes condições devem ser atendidas:
A instância do SQL Server que você está usando deve ter a integração CLR habilitada.

Para habilitar a integração CLR, execute as etapas a seguir:

Habilitando a integração CLR

Execute os seguintes comandos Transact-SQL:

sp_configure 'clr enabled', 1

RECONFIGURE

Observação
Para habilitar o CLR, é necessário ter a permissão ALTER SETTINGS de nível de servidor, que é mantida implicitamente por membros das funções de servidor fixas sysadmin e serveradmin.

O banco de dados AdventureWorks deve estar instalado na instância do SQL Server que você está usando.
Se não for um administrador da instância do SQL Server que está sendo usada, você deverá solicitar que um administrador lhe conceda a permissão CreateAssembly para concluir a instalação.

Compilando o exemplo

Crie e execute o exemplo seguindo estas instruções:

Abra um prompt de comando do Visual Studio ou do .NET Framework.
Se necessário, crie um diretório para seu exemplo. Para este exemplo, usaremos C:\MySample.
Em c:\MySample, crie Utf8String.vb (para o exemplo do Visual Basic) ou Utf8String.cs (para o exemplo do C#) e copie o código de exemplo adequado do Visual Basic ou do C# (a seguir) no arquivo.
Compile o código de exemplo no prompt de linha de comando executando uma das seguintes ações, de acordo com sua opção de linguagem.
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
Copie o código de instalação Transact-SQL em um arquivo e salve-o como Install.sql no diretório de exemplo.
Se o exemplo tiver sido instalado em um diretório diferente de C:\MySample\, edite o arquivo Install.sql conforme indicado para apontar para esse local.
Implante o assembly e o procedimento armazenado executando:
- sqlcmd -E -I -i install.sql
Copie o script de comando de teste Transact-SQL em um arquivo e salve-o como test.sql no diretório de exemplo.
Execute o script de teste com o seguinte comando
- sqlcmd -E -I -i test.sql
Copie o script de limpeza Transact-SQL em um arquivo e salve-o como cleanup.sql no diretório de exemplo.
Execute o script com o seguinte comando
- sqlcmd -E -I -i cleanup.sql

Código de exemplo

As listagens de código deste exemplo são as seguintes.

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

Esse é o script de instalação Transact-SQL (Install.sql) que implanta o assembly e cria o UDT no banco de dados.

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

Esse é o test.sql, que testa o exemplo por meio da execução do tipo.

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;

O Transact-SQL a seguir remove o assembly e o tipo do banco de dados.

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

Consulte também

Conceitos

Cenários de uso e exemplos para a integração de CLR (Common Language Runtime)

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