9 处理SQLCLR

9.1 SQLCLR能否取代T-SQL

SQL CLR是实现专门执行计算的程序的最佳选择

9.2 不使用Visual Studio创建存储过程

9.2.1 启用SqlClr

在management studio中运行如下查询代码启用服务器设置：

代码

--启用或禁用数据库的SQLCLR功能
--1, 启用SQLCLR
--0, 禁用SQLCLR
EXEC SP_CONFIGURE 'CLR ENABLED',1
RECONFIGURE WITH OVERRIDE

--获取SQLCLR的状态
EXEC SP_CONFIGURE 'CLR ENABLED'

--获取SQLCLR的属性
SELECT * FROM SYS.DM_CLR_PROPERTIES

 

9.2.2 创建源代码

代码

Imports  Microsoft.SqlServer.Server
Namespace  VbTestNamespace
     Public   Class  VbTestClass
         Public   Shared   Sub  SayHi()
            SqlContext.Pipe.Send( " Hi VB World from Sql server! " )
         End Sub
     End Class
End Namespace

 

 

9.2.3 使用上下文对象

9.2.4 编译代码

9.2.5 加载程序集

 

CREATE ASSEMBLY  VbProcs  FROM   ' c:\HiVbWorld.dll '
WITH PERMISSION_SET=SAFE
GO

 

 

9.2.6 修改执行权限

启用数据库Lake的trustWorthy属性

USE  MASTER
ALTER   DATABASE  Lake  SET  TRUSTWORTHY  ON

 

为CSL赋予EXTERNAL_ACCESS权限

USE  MASTER
GRANT  EXTERNAL ACCESS  ASSEMBLY  TO  CSL

 

为CSL赋予UNSAFE权限 

USE  MASTER
GRANT  UNSAFE  ASSEMBLY  TO  CSL

 

9.2.7 注册存储过程

 

CREATE PROCEDURE  SayVbHi
AS EXTERNAL NAME  VbProcs. [ VbTestNamespace.VbTestClass ] .SayHi

 

 

9.2.8 执行存储过程

9.2.9 刷新程序集

ALTER  ASSEMBLY VbProcs  FROM   ' c:\HiVbWorld.dll '
GO

 

 

9.2.10 查看已经安装的程序集及其权限

 

SELECT   *   FROM  sys.assemblies

 

 

9.2.11 使用参数传输数据

vb函数如下：

Public   Shared   Sub  GetGreeting( ByVal  name  As   String ,  ByRef  greeting  As   String )
    greeting  =   String .Format( " Hello from VB, {0} " , name)
End Sub

 

 

注册包含参数的vb存储过程

CREATE   PROCEDURE  GetVbGreeting
     @name   NVARCHAR ( 50 ),
     @greeting   NVARCHAR ( 100 ) OUTPUT
AS   EXTERNAL  NAME  VbProcs. [ VbTestNamespace.VbTestClass ] .GetGreeting

 

执行存储过程

 

DECLARE   @result   NVARCHAR ( 100 )
EXEC  GetVbGreeting  ' Glenn ' ,  @result  OUTPUT
PRINT   @result

 

 

9.3 使用Visual Studio创建存储过程

存储过程模板生成的代码：

代码

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


Partial   Public   Class  StoredProcedures
     < Microsoft.SqlServer.Server.SqlProcedure() >  _
     Public   Shared   Sub   StoredProcedures ()
         '  在此处添加您的代码
     End Sub
End Class

 

修改自动生成的代码得到以下代码：

< Microsoft.SqlServer.Server.SqlProcedure(Name: = " HiVb " ) >  _
Public   Shared   Sub  HelloVb()
    SqlContext.Pipe.Send( " Hello from VB! " )
End Sub

 

执行存储过程：

EXEC  HiVb

 

 

9.4 传递行集数据

9.4.1 传递代码中生成的行集数据

 

代码

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

Partial   Public   Class  StoredProcedures
     < Microsoft.SqlServer.Server.SqlProcedure(Name: = " GetVbWords " ) >  _
     Public   Shared   Sub  GetWords( ByVal  sentence  As   String )
         Dim  rec  As   New  SqlDataRecord( New  SqlMetaData( " Index " , SqlDbType.Int), _
                                      New  SqlMetaData( " Word " , SqlDbType.NVarChar,  50 ))
        SqlContext.Pipe.SendResultsStart(rec)

         Dim  i  =   0
         For   Each  word  As   String   In  sentence.Split( "   " c)
            rec.SetInt32( 0 , i)
            i  +=   1
            rec.SetString( 1 , word)
            SqlContext.Pipe.SendResultsRow(rec)
         Next
        SqlContext.Pipe.SendResultsEnd()
     End Sub
End Class

 

执行存储过程：

EXEC  GetVbWords  ' This is a test of the GetWords stored procedure '

 

9.4.1.1 在SQLCLR中使用SqlConnection对象

 

代码

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

Partial   Public   Class  StoredProcedures
     < Microsoft.SqlServer.Server.SqlProcedure() >  _
     Public   Shared   Sub  LastEmployeeOrdersVb()
         Dim  rec  As   New  SqlDataRecord( New  SqlMetaData( " EmployeeId " , SqlDbType.Int), _
                                      New  SqlMetaData( " LastOrders " , SqlDbType.NVarChar,  50 ))
         Dim  employees  As   New  DataTable( " Employees " )
         Using  cn  As   New  SqlConnection()
            cn.ConnectionString  =   " context connection=true "
             Using  cmd  =  cn.CreateCommand
                cmd.CommandText  =   " SELECT EmployeeId From Employees "  _
                                 &   "  Order by EmployeeId ASC "

                cn.Open()
                 Using  rdr  As  SqlDataReader  =  cmd.ExecuteReader
                    employees.Load(rdr)
                 End   Using
             End   Using

            SqlContext.Pipe.SendResultsStart(rec)
             For   Each  dr  As  DataRow  In  employees.Rows
                 Dim  empId  As   Integer   =  dr( " EmployeeId " )
                 Using  cmd  As  SqlCommand  =  cn.CreateCommand
                    cmd.CommandText  =   String .Format( " select top 3 OrderID from Orders  "  _
                                                     &   " Where EmployeeId={0}  "  _
                                                     &   " Order by OrderDate Desc " , empId)

                     Using  rdr  As  SqlDataReader  =  cmd.ExecuteReader
                         Dim  orders  As   String   =   ""
                         While  (rdr.Read)
                             If  orders.Length  >   0   Then  orders  &=   " ,  "
                            orders  &=  rdr( 0 ).ToString
                         End   While
                        rec.SetInt32( 0 , empId)
                        rec.SetString( 1 , orders)
                        SqlContext.Pipe.SendResultsRow(rec)
                     End   Using
                 End   Using
             Next
         End   Using
        SqlContext.Pipe.SendResultsEnd()
     End Sub
End Class

 

 

9.4.2 传递数据库行集中的数据

 

代码

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

Partial   Public   Class  StoredProcedures
     < Microsoft.SqlServer.Server.SqlProcedure() >  _
     Public   Shared   Sub  GetCustomersVb()
         Using  cn  As   New  SqlConnection()
            cn.ConnectionString  =   " context connection=true "
             Using  cmd  As  SqlCommand  =  cn.CreateCommand
                cmd.CommandText  =   " Select * from Customers "
                cn.Open()
                 Using  rdr  As  SqlDataReader  =  cmd.ExecuteReader
                    SqlContext.Pipe.Send(rdr)
                 End   Using
             End   Using
         End   Using
     End Sub
End Class

 

使用SqlContext.Pipe.ExecuteAndSend方法简化代码

 

代码

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

Partial   Public   Class  StoredProcedures
     < Microsoft.SqlServer.Server.SqlProcedure() >  _
     Public   Shared   Sub  GetCustomersVb()
         Using  cn  As   New  SqlConnection()
            cn.ConnectionString  =   " context connection=true "
             Using  cmd  As  SqlCommand  =  cn.CreateCommand
                cmd.CommandText  =   " Select * from Customers "
                cn.Open()
                SqlContext.Pipe.ExecuteAndSend(cmd)
             End   Using
         End   Using
     End Sub
End Class

  

9.5 创建用户自定义函数

9.5.1 使用标量函数

 标量函数的定义：

代码

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

Partial   Public   Class  StoredProcedures
     < Microsoft.SqlServer.Server.SqlFunction() >  _
     Public   Shared   Function  PadVb( ByVal  inputValue  As   Integer ,  ByVal  width  As   Integer )  As  SqlString
         Return   New  SqlString(inputValue.ToString.PadLeft(width,  " 0 " c))
     End Function
End Class

 

测试：

SELECT  dbo.PadVb(supplierid, 5 )  as  ID, CompanyName  FROM  suppliers

  

9.5.2 使用流表值函数(TVF)

代码

Imports  System
Imports  System.Data
Imports  System.Data.SqlClient
Imports  System.Data.SqlTypes
Imports  Microsoft.SqlServer.Server
Imports  System.IO
Imports  System.Security.Principal

Partial   Public   Class  UserDefinedFunctions
     < Microsoft.SqlServer.Server.SqlFunction( _
    FillRowMethodName: = " FillRow " , _
    TableDefinition: = " Name nvarchar(32), Length bigint, Modified DateTime " , _
    SystemDataAccess: = SystemDataAccessKind.Read) >  _
     Public   Shared   Function  FileList( ByVal  directoryName  As   String , _
                                     ByVal  pattern  As   String )  As  IEnumerable

         Dim  files()  As  FileInfo
         Dim  OriginalContext  As  WindowsImpersonationContext
        OriginalContext  =  SqlContext.WindowsIdentity.Impersonate

         Try
             Dim  di  As   New  DirectoryInfo(directoryName)
            files  =  di.GetFiles(pattern)
         Finally
             If  OriginalContext  IsNot   Nothing   Then
                OriginalContext.Undo()
             End   If
         End   Try
         Return  files
     End Function

     ' the fill row method that cracks the FileRecord
     ' and returns the individual columns.
     Public   Shared   Sub  FillRow( ByVal  obj  As   Object , _
                               ByRef  fileName  As  SqlString, _
                               ByRef  fileLength  As  SqlInt64, _
                               ByRef  fileModified  As  SqlDateTime)
         If  obj  IsNot   Nothing   Then
             Dim  file  As  FileInfo  =  obj
            fileName  =  file.Name
            fileLength  =  file.Length
            fileModified  =  file.LastWriteTime
         Else
            fileName  =  SqlString.Null
            fileLength  =  SqlInt64.Null
            fileModified  =  SqlDateTime.Null
         End   If
     End Sub
End Class

 

 

测试：

SELECT   *   FROM  dbo.FileListVb( ' C:\ ' , ' *.* ' )

  

9.6 处理用户自定义聚集 

代码

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

< Serializable() >  _
< Microsoft.SqlServer.Server.SqlUserDefinedAggregate( _
     Format .Native, isNullIfEmpty: = True , isInvariantToNulls: = True ) >  _
Public   Structure  DateTimeSpanVb

     Private  minDate  As  SqlDateTime
     Private  maxDate  As  SqlDateTime

     Public   Sub  Init()
        minDate  =  SqlDateTime.Null
        maxDate  =  SqlDateTime.Null
     End Sub

     Public   Sub  Accumulate( ByVal  value  As  SqlDateTime)
         If  value.IsNull  Then   Return
         If  minDate.IsNull  Or  value.CompareTo(minDate)  <   0   Then
            minDate  =  value
         End   If
         If  maxDate.IsNull  Or  value.CompareTo(maxDate)  >   0   Then
            maxDate  =  value
         End   If
     End Sub

     Public   Sub  Merge( ByVal  Group  As  DateTimeSpanVb)
        Accumulate(Group.minDate)
        Accumulate(Group.maxDate)
     End Sub

     Public   Function  Terminate()  As  SqlString
         If  maxDate.IsNull  Or  minDate.IsNull  Then   Return  SqlString.Null

         Dim  ts  As  TimeSpan  =  maxDate.Value  -  minDate.Value

         Return   New  SqlString(ts.ToString)
     End Function
End Structure

 

 

 

测试：

SELECT  dbo.DateTimeSpanVb(ShippedDate)  AS  TimeSpan

 

另一个用户自定义聚集示例：

 

代码

Imports  System
Imports  System.Data
Imports  System.Data.SqlClient
Imports  System.Data.SqlTypes
Imports  Microsoft.SqlServer.Server
Imports  System.Collections.Generic

Imports  System.IO

< Serializable() >  _
< SqlUserDefinedAggregate( Format .UserDefined, _
    IsInvariantToNulls: = True , IsInvariantToDuplicates: = False , IsInvariantToOrder: = False , _
    MaxByteSize: = 8000 ) >  _
Public   Structure  JoinString
     Implements  IBinarySerialize

     Private  items  As  List( Of   String )

     Public   Sub  Init()
        items  =   New  List( Of   String )
     End Sub

     Public   Sub  Accumulate( ByVal  value  As  SqlString)
         If  value.IsNull  Then   Return
        items.Add(value.ToString())
     End Sub

     Public   Sub  Merge( ByVal  Group  As  JoinString)
        items.AddRange(Group.items)
     End Sub

     Public   Function  Terminate()  As  SqlString
         Return   New  SqlString( String .Join( " , " c, items.ToArray))
     End Function

     Public   Sub  Read( ByVal  r  As  BinaryReader)  Implements  Microsoft.SqlServer.Server.IBinarySerialize.Read
        items  =   New  List( Of   String )
         Dim  count  =  r.ReadInt32()
         For  i  =   0   To  count  -   1
            items.Add(r.ReadString())
         Next
     End Sub

     Public   Sub   Write ( ByVal  w  As  BinaryWriter)  Implements  Microsoft.SqlServer.Server.IBinarySerialize.Write
        w.Write(items.Count)
         For  i  =   0   To  items.Count  -   1
            w.Write(items(i))
         Next
     End Sub
End Structure

 

 

9.7 处理触发器

 

代码

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

Partial   Public   Class  Triggers
     < Microsoft.SqlServer.Server.SqlTrigger( _
        Name: = " ReturnDifferenceVb " , Target: = " Products " ,  Event : = " FOR UPDATE " ) >  _
     Public   Shared   Sub  ReturnDifferenceVb()
         Using  cn  As   New  SqlConnection()
            cn.ConnectionString  =   " Context connection=true "
            cn.Open()
             Using  cmd  As  SqlCommand  =  cn.CreateCommand
                cmd.CommandText  =   " SELECT i.ProductID,(i.UnitPrice-d.UnitPrice) AS AmountChanged "  _
                         &   " FROM INSERTED i JOIN DELETED d ON i.ProductID=d.ProductID  "  _
                         &   " ORDER BY ProductID ASC "

                SqlContext.Pipe.ExecuteAndSend(cmd)
             End   Using
         End   Using
     End Sub
End Class

 

9.8 处理用户自定义类型

 

代码

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

< Serializable() >  _
< Microsoft.SqlServer.Server.SqlUserDefinedType( Format .Native) >  _
Public   Structure  DistanceVb
     Implements  INullable, IComparable

     Public   ReadOnly   Property  Feet  As   Integer
         Get
             Return   CInt (totalInches  /   12 )
         End   Get
     End Property

     Public   ReadOnly   Property  Inches  As   Integer
         Get
             Return  totalInches  Mod   12
         End   Get
     End Property

     Public   Overrides   Function  ToString()  As   String
         '  Put your code here
         Return   String .Format( " {0 ft. {1} in. " , Feet, Inches)
     End Function

     Public   ReadOnly   Property  IsNull()  As   Boolean   Implements  INullable.IsNull
         Get
             '  Put your code here
             Return  m_Null
         End   Get
     End Property

     Public   Shared   ReadOnly   Property  Null  As  DistanceVb
         Get
             Dim  h  As  DistanceVb  =   New  DistanceVb
            h.m_Null  =   True
             Return  h
         End   Get
     End Property

     Public   Shared   Function  Parse( ByVal  s  As  SqlString)  As  DistanceVb
         If  s.IsNull  Then
             Return  Null
         End   If
         Dim  u  As  DistanceVb  =   New  DistanceVb
         '  Put your code here
         Dim  distance  As   String   =  s.Value
         If  distance  =   " null "   Then   Return  Null
        distance  =  distance.ToLower
         Dim  feet  As   Integer   =   0
         Dim  inches  As   Integer   =   0
         Dim  parts()  As   String   =  distance.Split( "   " c)
         Dim  feetLocation  As   Integer   =  Array.IndexOf(parts,  " ft. " )
         If  feetLocation  >   0   Then
            feet  =   Integer .Parse(parts(feetLocation  -   1 ))
         End   If
         Dim  inchesLocation  As   Integer   =  Array.IndexOf(parts,  " in. " )
         If  inchesLocation  >   0   Then
            inches  =   Integer .Parse(parts(inchesLocation  -   1 ))
         End   If
        u.totalInches  =  (feet  *   12 )  +  inches
         Return  u
     End Function

     Function  CompareTo( ByVal  obj  As   Object )  As   Integer  _
         Implements  icomparable.compareto
         Dim  other  As  DistanceVb  =   CType (obj, DistanceVb)
         Return  totalInches  -  other.totalInches
     End Function

     Public  totalInches  As   Integer
     Private  m_Null  As   Boolean
End Structure

 

 

测试UDT:

代码

create   table  UdtTestVb(Id  int   not   null , distance distancevb  not   null )

insert   into  UdtTestVb  values ( 1 , ' 2 ft. 5 in. ' )
insert   into  UdtTestVb  values ( 2 , ' 15 in. ' )
insert   into  UdtTestVb  values ( 3 , ' 10 ft. ' )
insert   into  UdtTestVb  values ( 4 , ' 1 ft. 23 in. ' )

select  id,  convert ( nvarchar ( 25 ),distance)  from  UdtTestVb
drop   table  UdtTestVb

 

 

9.8.1 何时不使用UDT

9.8.2 何时使用UDT

 

代码

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

< Serializable() >  _
< Microsoft.SqlServer.Server.SqlUserDefinedType( Format .Native) >  _
Public   Structure  StringStuffVb
     Implements  INullable

     Public   Shared   Function  PadLeft(
                                   ByVal   inputString   As  SqlString,
                                   ByVal  totalWidth  As  SqlInt32)  As  SqlString
         Return   New  SqlString(
             inputString .Value.PadLeft(totalWidth.Value))
     End Function

     Public   Shared   Function  PadRight(
                                   ByVal   inputString   As  SqlString,
                                   ByVal  totalWidth  As  SqlInt32)  As  SqlString
         Return   New  SqlString(
             inputString .Value.PadRight(totalWidth.Value))
     End Function

     Public   Overrides   Function  ToString()  As   String
         '  Put your code here
         Return   ""
     End Function

     Public   ReadOnly   Property  IsNull()  As   Boolean   Implements  INullable.IsNull
         Get
             '  Put your code here
             Return  m_Null
         End   Get
     End Property

     Public   Shared   ReadOnly   Property  Null  As  StringStuffVb
         Get
             Dim  h  As  StringStuffVb  =   New  StringStuffVb
            h.m_Null  =   True
             Return  h
         End   Get
     End Property

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

         Dim  u  As  StringStuffVb  =   New  StringStuffVb
         '  Put your code here
         Return  u
     End Function

     '  Private member
     Private  m_Null  As   Boolean
End Structure

 

测试代码，使用UDT中的静态方法：

select   ' < ' + stringstuffvb::padleft( ' Hi ' , 10 ) + ' > '
select   ' < ' + stringstuffvb::padright( ' Hi ' , 10 ) + ' > '

  

9.9 在客户端访问SqlClr特征

 

代码

Imports  System.Data.SqlClient

Public   Class  Form1

     Private   Sub  Button1_Click( ByVal  sender  As  System.Object,
                               ByVal  e  As  System.EventArgs)  Handles  Button1.Click
         Using  cn  As   New  SqlConnection
            cn.ConnectionString  =
                 " server=.\sqlexpress;Initial Catalog=northwind;Integrated Security=True "
             Using  cmd  As  SqlCommand  =  cn.CreateCommand
                cmd.CommandText  =
                     " create table UdtTestVb(Id int not null,Distance distanceVb not null) "
                cn.Open()
                cmd.ExecuteNonQuery()
                cmd.CommandText  =
                     " insert into UdtTestVb values(@Id,@distance) "
                 Dim  id  As  SqlParameter  =  cmd.CreateParameter
                id.ParameterName  =   " @id "
                id.DbType  =  DbType.Int32

                 Dim  distance  As  SqlParameter  =  cmd.CreateParameter
                distance.ParameterName  =   " @distance "
                distance.SqlDbType  =  SqlDbType.Udt
                distance.UdtTypeName  =   " DistanceVb "

                cmd.Parameters.Add(id)
                cmd.Parameters.Add(distance)

                id.Value  =   1
                distance.Value  =  distanceVb.Parse( " 2 ft. 5 in. " )
                cmd.ExecuteNonQuery()

                id.Value  =   2
                distance.Value  =  DistanceVb.Parse( " 15 in. " )
                cmd.ExecuteNonQuery()

                id.Value  =   3
                distance.Value  =  DistanceVb.Parse( " 10 ft. " )
                cmd.ExecuteNonQuery()

                id.Value  =   4
                distance.Value  =  DistanceVb.Parse( " 1 ft. 23 in. " )
                cmd.ExecuteNonQuery()

                cmd.CommandText  =   " SELECT id, convert(nvarchar(25),distance) FROM UdtTestVb "
                cmd.Parameters.Clear()
                 Dim  testTable  As   New  DataTable
                testTable.Load(cmd.ExecuteReader)
                DataGridView1.DataSource  =  testTable

                cmd.CommandText  =   " drop table UdtTestVb "
                cmd.ExecuteNonQuery()
             End   Using
         End   Using
     End Sub
End Class