UTF8 String User-Defined Data Type (UDT)

Образец UTF8String для SQL Server демонстрирует реализацию определяемого пользователем типа данных. Этот образец показывает реализацию определяемого пользователем типа данных UTF8, который расширяет систему типов базы данных, обеспечивая возможность хранения значений в кодировке UTF8. Этот тип также реализует программный код для преобразования строк в Юникоде в формат UTF8 и обратно.

Предварительные требования

Для создания и запуска этого проекта должно быть установлено следующее программное обеспечение:

SQL Server или SQL Server Express. SQL Server Express можно получить бесплатно с веб-сайтадокументации и образцов SQL Server Express (возможно, на английском языке)
База данных AdventureWorks, которая доступна на веб-сайте разработки SQL Server (возможно, на английском языке).
Пакет SDK 2.0 для платформы .NET Framework или более поздняя версия либо среда Microsoft Visual Studio 2005 или более поздняя версия. Пакет SDK для платформы .NET Framework можно получить бесплатно.
Кроме того, должны выполняться следующие условия.
Для используемого экземпляра SQL Server должна быть включена интеграция со средой CLR.

Чтобы включить интеграцию со средой CLR, выполните следующие действия.

Включение интеграции со средой CLR

Выполните следующие команды Transact-SQL:

sp_configure 'clr enabled', 1

RECONFIGURE

Примечание
Чтобы включить CLR, необходимо иметь разрешение ALTER SETTINGS на уровне сервера, которое неявно назначается членам предопределенных ролей сервера sysadmin и serveradmin.

На используемом экземпляре SQL Server должна быть установлена база данных AdventureWorks.
Если вы не являетесь администратором используемого экземпляра SQL Server, то для завершения установки необходимо, чтобы администратор предоставил разрешение CreateAssembly .

Построение образца

Создайте и запустите образец в соответствии со следующими инструкциями.

Откройте командную строку Visual Studio или .NET Framework.
Если необходимо, создайте каталог для своего образца. В данном примере будет использоваться каталог C:\MySample.
В каталоге c:\MySample создайте файл Utf8String.vb (для образца на языке Visual Basic) или Utf8String.cs (для образца на языке C#) и скопируйте в него соответствующий образец кода на языке Visual Basic или C# (ниже).
Скомпилируйте образец кода из командной строки, выполнив одну из следующих команд, в зависимости от выбранного языка.
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
Скопируйте код установки Transact-SQL в файл и сохраните его в файле Install.sql в том же каталоге.
Если образец установлен в каталоге, отличном от C:\MySample\, внесите изменения в файл Install.sql, указав там этот каталог.
Разверните сборку и хранимую процедуру, выполнив
- sqlcmd -E -I -i install.sql
Скопируйте скрипт проверки Transact-SQL в файл и сохраните его в файле test.sql в том же каталоге.
Выполните скрипт проверки следующей командой
- sqlcmd -E -I -i test.sql
Скопируйте скрипт очистки Transact-SQL в файл и сохраните его в файле cleanup.sql в том же каталоге.
Выполните скрипт следующей командой
- sqlcmd -E -I -i cleanup.sql

Образец кода

Ниже приведены листинги кода для данного образца.

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

Это скрипт установки Transact-SQL (Install.sql), который выполняет развертывание сборки и создает в базе данных определяемый пользователем тип.

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

Это файл test.sql, который проверяет образец, тестируя его тип.

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;

В следующем образце Transact-SQL сборка и тип удаляются из базы данных.

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

См. также

Основные понятия

Сценарии использования и примеры интеграции со средой CLR

Last updated on 2013-05-07