SQL中的CDC

SQL中的CDC 变更数据捕获

1.有时候我们需要知道cdc捕获的数据中（仅修改举例），哪些列是修改列，于是写了个存储过程，如下：

if exists
(
    select *
    from sys.procedures
    where name = 'c_fn_cdc_parsingName'
)
    drop procedure c_fn_cdc_parsingName;
go
create procedure c_fn_cdc_parsingName
(
    @tbl nvarchar(1000) --cdc生成的表名，如dbo_aaa
  , @update_mask varbinary(128) --_$update_mask列通过位图显示在_$operation 指定的DML 操作中更新了哪些列。如果这是一个 DELETE 或 INSERT 操作，则所有列都将被更新，因此掩码包含其中全为 1 的值。该掩码包含由位值形成的值。
)
as
begin
    declare @str          nvarchar(max)
          , @change_table nvarchar(1000)
          , @i            int
          , @j            int;
    set @str = N'';
    set @change_table = N'[cdc].' + quotename(rtrim(@tbl) + N'_CT');
    if exists (select * from sys.tables where name = 'temp_column')
    begin
        drop table temp_column;
    end;
    select row_number() over (order by a.column_id asc) as [rows]
         , a.[name]
    into temp_column
    from sys.columns a
    where object_id = object_id(@change_table);
    select @i = count(*)
    from dbo.temp_column;
    set @j = 1;
    while (@j < @i)
    begin
        declare @Name nvarchar(100)
              , @num  int
              , @isOk bit;
        select @Name = name
        from temp_column
        where rows = @j;

        select @num = [sys].[fn_cdc_get_column_ordinal](rtrim(@tbl), @Name);
        select @isOk = [sys].[fn_cdc_is_bit_set](@num, @update_mask);
        if @isOk = 1
        begin
            set @str = @str + @Name + N',';
            print @str
        end;
        set @j = @j + 1;
    end;
    select left(@str,len(@str)-1) ;
end; 

合并修改列到结果集

if exists (select * from sys.procedures where name = 'p_NewDATA')
    drop procedure p_NewDATA;
go
create procedure p_NewDATA
(@tbl nvarchar(1000),@operation int)
as
begin
    if exists (select * from sys.tables where name = 'temp_NameTbl')
    begin
        drop table temp_NameTbl;
    end;

    declare @i int
          , @j int;


    select row_number() over (order by cInvCode asc) as [rows]
         , cast(N'' as nvarchar(max))                as UpdateInfo
         , *
    into temp_NameTbl
    from cdc.dbo_inventory_CT
    where __$operation = @operation;

    set @i =
    (
        select count(*) from temp_NameTbl where __$operation = @operation
    );

    set @j = 1;
    while (@j < @i)
    begin

        declare @update_mask varbinary(128)
              , @strName     nvarchar(max);
        set @strName = N'';
        create table #temp
        (
            id int primary key identity(1, 1)
          , strName nvarchar(max)
        );
        set @update_mask =
        (
            select __$update_mask from temp_NameTbl where rows = @j
        );



        insert into #temp
        (
            strName
        ) exec c_fn_cdc_parsingName @tbl, @update_mask;


        select @strName = strName
        from #temp;

        update temp_NameTbl
        set UpdateInfo = @strName
        from dbo.temp_NameTbl
        where rows = @j;

        set @j = @j + 1;
        drop table #temp;
    end;

    select *
    from temp_NameTbl;

end;

有关于SQL中cdc的知识