存储过程使用表变量或临时表代替游标Fetch实例，访问远程数据库

定义表变量是可以直接操作在内存中的数据，比较快。临时表在大数据量时会比游标使用的资源少。还是要看具体情况了。也有可能在实际优化过程中相互替换呢。

留作记忆的代码如下：

if object_id('tempdb..#Tmp') is not null
Begin
    drop table #Tmp
End
    
        create table #Tmp  --创建临时表#Tmp为获取远程设备信息使用
        (
            deviceId varchar(50),
            deviceNo varchar(200),            
            FlagID   TINYINT 
        );    
declare @i int,--执行一条sql语句的临时变量,用于远程数据库配置信息循环
        @j int,--执行一条sql语句的临时变量，用于更新设备信息名称
        @user varchar(50),--用户名
        @password varchar(100),--密码
        @ssid varchar(100),--ssid
        @db varchar(100),--数据库名称
        @server varchar(100),--远程数据库server
        @database varchar(200),
        @remoteid int
--定义远程数据库配置信息临时表        
declare @tRemoteOffice table
        (
            RemoteId int,
            RomoteUser varchar(50),
            RemotePassword varchar(100),
            RemoteSsid varchar(100),
            RemoteDb varchar(100),
            RemoteName varchar(100),
            FlagID   TINYINT
        )
        
        begin
        
        
        BEGIN TRY---------------------开始捕捉异常
            

        --1.查询远程数据库配置表，插入查询数据到临时表
        insert @tRemoteOffice select remote_id, remote_user,remote_psw,remote_ssid,remote_database,remote_name,0 from dbo.RemoteDBInfo;
        print CONVERT(varchar(100), GETDATE(),21)+'插入远程数据库配置信息到临时表，一共执行'+convert(varchar(5),@@ROWCOUNT)+'条'
        
        set @i=1;
        --Return_connectError:
        while(@i>=1)
            begin
            Return_begin:
            --2.选取临时表里的一条数据 
            SELECT TOP 1 @remoteid=RemoteId, @user = RomoteUser,@password=RemotePassword,@ssid=RemoteSsid,@db=RemoteDb,@server=RemoteName FROM @tRemoteOffice  WHERE FlagID=0; 
            SET @i=@@ROWCOUNT
            IF @i<=0 GOTO Return_Lab 
            print '开始连接远程数据库,ssid:'+@ssid;
            begin try
            --3.连接远程数据库
            exec   sp_addlinkedserver     @server, ' ', 'SQLOLEDB', @ssid ;
            exec   sp_addlinkedsrvlogin   @server, 'false ',null, @user, @password ;
            
            select @database=@server+'.'+@db;
            --4.查询远程数据库的机构信息
            declare @officeID nvarchar(50),
                    @officeName nvarchar(200)
                    
            declare @searchRemoteOfficeSql Nvarchar(max)=N'SELECT @Id=office_id,@Name=office_name FROM  '+@database+'.dbo.Office where caste=0';
            Exec sp_executesql @searchRemoteOfficeSql,N'@Id nvarchar(50) output,@Name nvarchar(100) output',@officeID output,@officeName output;
            
            print CONVERT(varchar(100), GETDATE(),21)+'查询远程数据库机构信息，一共执行'+convert(varchar(5),@@ROWCOUNT)+'条'
            update dbo.RemoteDBInfo set remote_type=1 WHERE remote_ssid = @ssid ;
            end try
            begin catch
                print '连接远程数据库'+@ssid+'异常'
                exec sp_dropserver  @server, 'droplogins ';
                UPDATE @tRemoteOffice SET FlagID=1 WHERE RemoteSsid = @ssid; 
                update dbo.RemoteDBInfo set remote_type=0 WHERE remote_ssid = @ssid ;
                goto Return_begin
            end catch
            --5.查询已连接的远程数据库officeid是否已在本地表中
            declare @SearchLocalUnitySql Nvarchar(max)=N'select UnityId from dbo.Unity where UnityId =@Id ';            
            Exec sp_executesql @SearchLocalUnitySql,N'@Id nvarchar(50)',@Id=@officeID;
            
            --6.不在本地表中，插入新的机构信息
            if @@ROWCOUNT=0
                begin
                
                declare @InsertUnityOfficeSql Nvarchar(max)=N'insert into dbo.Unity (UnityId,Name,ParentId,Type,remote_id) values(@id,@name,NULL,0,@remote_id) ';
                Exec sp_executesql @InsertUnityOfficeSql,N'@id nvarchar(50),@name nvarchar(200),@remote_id int',@id=@officeID,@name=@officeName,@remote_id=@remoteid;
                print CONVERT(varchar(100), GETDATE(),21)+'插入新的机构信息，一共执行'+convert(varchar(5),@@ROWCOUNT)+'条'
                end
            --7.在本地表中，更新机构名称    
            else
                begin
                declare @UpdateUnityOfficeNameSql Nvarchar(max)=N'update dbo.Unity set Name=@Name1,remote_id=@remote_id where UnityId=@Id1 ';
                Exec sp_executesql @UpdateUnityOfficeNameSql,N'@Name1 nvarchar(100),@Id1 nvarchar(50),@remote_id int',@Name1=@officeName,@Id1=@officeID,@remote_id=@remoteid;
                print CONVERT(varchar(100), GETDATE(),21)+'更新机构信息，一共执行'+convert(varchar(5),@@ROWCOUNT)+'条'
                end
                
            
                        
            --8.插入设备信息到临时表
            truncate table #Tmp
            declare @deviceID varchar(50),
                    @deviceName varchar(200)
            
            declare @InsertRemoteDeviceSql Nvarchar(max)=N'insert #Tmp select device_id,device_no,0 FROM  '+@server+'.'+@db+'.dbo.device where parent_id is null and is_bom=0 and status=1 ';
            Exec sp_executesql @InsertRemoteDeviceSql;
            print CONVERT(varchar(100), GETDATE(),21)+'插入设备信息到临时表，一共执行'+convert(varchar(5),@@ROWCOUNT)+'条'
            set @j=1;
            while(@j>=1)
                begin
                --9.选取临时表里的一条数据 
                SELECT TOP 1 @deviceID = deviceId,@deviceName=deviceNo FROM #Tmp  WHERE FlagID=0; 
                SET @j=@@ROWCOUNT
                IF @j<=0 GOTO Return_device 
                --10.查询临时表里的deviceId是否在Unity里
                declare @SearchLocalUnityDeviceSql Nvarchar(max)=N'select UnityId from dbo.Unity where UnityId =@id ';
                Exec sp_executesql @SearchLocalUnityDeviceSql,N'@id nvarchar(50)',@id=@deviceID;
                --@@ROWCOUNT被执行一次后清零
                --print CONVERT(varchar(100), GETDATE(),21)+'查询临时表里的设备id是否在Unity里，一共执行'+convert(varchar(5),@@ROWCOUNT)+'条'
                --11.不在表数据里，插入新的设备信息
                if    @@ROWCOUNT=0
                    begin
                    
                    declare @InsertUnityDeviceSql Nvarchar(max)=N'insert into dbo.Unity (UnityId,Name,ParentId,Type) values (@id,@name,@parentid,1) ';
                    Exec sp_executesql @InsertUnityDeviceSql,N'@id nvarchar(50),@name nvarchar(200),@parentid nvarchar(50)',@id=@deviceID,@name=@deviceName,@parentid=@officeID;
                    print CONVERT(varchar(100), GETDATE(),21)+'插入新的设备信息，一共执行'+convert(varchar(5),@@ROWCOUNT)+'条'
                    end
                --12.在表数据里，更新设备名称    
                else
                    begin
                    declare @UpdateUnityDeviceNameSql Nvarchar(max)=N'update dbo.Unity set Name=@name where UnityId=@id ';
                    Exec sp_executesql @UpdateUnityDeviceNameSql,N'@name nvarchar(200),@id nvarchar(50)',@name=@deviceName,@id=@deviceID;
                    print CONVERT(varchar(100), GETDATE(),21)+'更新设备名称，一共执行'+convert(varchar(5),@@ROWCOUNT)+'条'
                    end
                    
                --13.获取本地FireReport表的最新数据时间
                declare @fireReportTime DateTime
                declare @SearchFireReportTime Nvarchar(max)=N'SELECT top 1 @time=FindTime FROM dbo.FireReport where UnityId=@id order by FindTime desc';
                Exec sp_executesql @SearchFireReportTime,N'@time Datetime output,@id nvarchar(50)',@fireReportTime output,@id=@deviceID;
                --14.插入火情信息数据
                if @fireReportTime=null
                    begin
                    set @fireReportTime=GETDATE();
                    end
                    
                    --0 未处理，1确认，2误报，3取消，4上报，5未知状态
                    declare @InsertFireSql Nvarchar(max)=N'insert into dbo.FireReport(FindTime,FireType,UnityId) 
                                                            select raised_dt
                                                            ,CASE WHEN confirmed = 0 and cancelled=0 and discarded=0 and reported=0  THEN 0
                                                            WHEN confirmed = 1 and cancelled=0 and discarded=0 and reported=0 THEN 1
                                                            WHEN confirmed = 0 and cancelled=0 and discarded=1 and reported=0 THEN 2
                                                            WHEN confirmed = 0 and cancelled=3 and discarded=0 and reported=0 THEN 3
                                                            WHEN confirmed = 0 and cancelled=0 and discarded=0 and reported=4 THEN 4
                                                            ELSE 5 END,@id FROM  '+@server+'.'+@db+'.dbo.fire where raised_dt>@time and  tower_id=@id order by raised_dt desc';
                    Exec sp_executesql @InsertFireSql,N'@id nvarchar(50),@time DateTime',@id=@deviceID,@time=@fireReportTime;
                    print CONVERT(varchar(100), GETDATE(),21)+'.插入火情信息数据，一共执行'+convert(varchar(5),@@ROWCOUNT)+'条'
                    

                --15.插入设备状态数据    
                --首先判断在视图中是否存在设备运行状态
                declare @SearchViewSql Nvarchar(max)=N'SELECT tower_id  FROM  '+@server+'.'+@db+'.dbo.vw_cruise_state where tower_id=@id ';
                Exec sp_executesql @SearchViewSql,N'@id nvarchar(50)',@id=@deviceID;
                if @@ROWCOUNT>0
                    begin
                    declare @InsertDeviceStatusSql Nvarchar(max)=N'Insert into dbo.DeviceStatus(UnityID,GetTime,Status) SELECT  tower_id,GETDATE(),aa_status  FROM  '+@server+'.'+@db+'.dbo.vw_cruise_state where tower_id=@id ';
                    Exec sp_executesql @InsertDeviceStatusSql,N'@id nvarchar(50)',@id=@deviceID;
                    print CONVERT(varchar(100), GETDATE(),21)+'插入设备运行状态数据，一共执行'+convert(varchar(5),@@ROWCOUNT)+'条';
                    print CONVERT(varchar(100), GETDATE(),21)+'设备ID为：'+@deviceID;
                    end        
                
                IF @@error=0   
                    UPDATE #Tmp SET FlagID=1 WHERE deviceId = @deviceID 
                    
                Return_device:
                end
                truncate table #Tmp;

            exec sp_dropserver  @server, 'droplogins '; 
            IF @@error=0   
                UPDATE @tRemoteOffice SET FlagID=1 WHERE RemoteSsid = @ssid  
            
            Return_Lab:  
            end
        DROP TABLE [dbo].#Tmp
            
        END TRY-----------结束捕捉异常
        
        BEGIN CATCH------------有异常被捕获
        print @@error;
        --IF @@TRANCOUNT > 0---------------判断有没有事务
        --BEGIN
        --    ROLLBACK TRAN----------回滚事务
        --END 
            print ERROR_MESSAGE();
            UPDATE @tRemoteOffice SET FlagID=1 WHERE RemoteSsid = @ssid; 
            exec sp_dropserver  @server, 'droplogins '; -----------执行存储过程将错误信息记录在表当中
        END CATCH--------结束异常处理
    
        end