sp_MSuniquename (Transact-SQL MetaData) Definition

Please note: that the following source code is provided and copyrighted by Microsoft and is for educational purpose only.
The meta data is from an SQL 2012 Server.

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Definition:

sys.sp_MSuniquename(nvarchar @seed
, int @start)

MetaData:

   
create procedure sys.sp_MSuniquename  
    @seed nvarchar(128), @start int = null  
as  
    --  Return a unique name for sysobjects, based on a passed-in seed.  --   
    set nocount on  
    declare @i int, @append nvarchar(10), @seedlen int, @temp nvarchar(128), @recalcseedlen int, @seedcharlen int  
    select @i = 1, @seedlen = datalength(@seed), @recalcseedlen = 1, @seedcharlen = 0  
    if (@start is not null and @start >= 0)  
        select @i = @start  
    while 1 < 2  
    begin  
        --  This is probably overkill, but start at max length of seed name, leaving room under OSQL_DBLSYSNAME_SET for @append.  --   
        --  We'll work our way back along the string if more room needed (pathological user).  --   
        select @append = ltrim(str(@i)) + N'__' + ltrim(str(@@spid))  
        if (@recalcseedlen = @i or @seedcharlen = 0)  
        begin  
            while @recalcseedlen <= @i  
                select @recalcseedlen = @recalcseedlen * 10  
            select @seedcharlen = @seedlen  
            if ((@seedlen + datalength(@append)) > 128) begin  
                select @seedlen = 128 - datalength(@append)  
  
                --  Get the charlen of this datalength for the substring() call.  --   
                select @seedcharlen = @seedlen  
               --  exec sp_GetMBCSCharLen @seed, @seedlen, @seedcharlen out  --   
            end        --  Recalc seedlen  --   
        end        --  Check seedlen  --   
  
        select @temp = substring(@seed, 1, @seedcharlen) + @append  
  
        --  If I don't set a limit somewhere, it's gonna look hung --  I'd rather get a nonunique error.  --   
        if object_id(@temp) is null or @i > 999999        --  if increased, watch out for overflow of @recalcseedlen  --   
        begin  
            set nocount off  
            select Name = @temp, Next = @i + 1  
            return 0  
        end  
        select @i = @i + 1  
    end