SQL Server執行問題

Question

exec sp_columns tablename調用是否修改表中的任何數據？

Answer 1

要找到它的位置，EXEC這樣：

exec sp_helptext 'sp_columns' 

你會得到這個存儲過程的文本：

create procedure sys.sp_columns 
(
    @table_name   nvarchar(384), 
    @table_owner  nvarchar(384) = null, 
    @table_qualifier sysname = null, 
    @column_name  nvarchar(384) = null, 
    @ODBCVer   int = 2 
) 
as 
    declare @full_table_name nvarchar(769) -- 384 + 1 + 384 
    declare @table_id   int 
    declare @fUsePattern  bit 

    select @fUsePattern = 1 

    if (@ODBCVer is null) or (@ODBCVer <> 3) 
     select @ODBCVer = 2 

    if @table_qualifier is not null 
    begin 
     if db_name() <> @table_qualifier 
     begin -- If qualifier doesn't match current database 
      raiserror (15250, -1,-1) 
      return 
     end 
    end 

    -- "ALL" is represented by NULL value. 
    if @table_name = '%' 
     select @table_name = null 
    if @table_owner = '%' 
     select @table_owner = null 
    if @table_qualifier = '%' 
     select @table_qualifier = null 
    if @column_name = '%' 
     select @column_name = null 

    -- Empty string means nothing, so use invalid identifier. 
    -- A quoted space will never match any object name. 
    if @table_owner = '' 
     select @table_owner = ' ' 

    select @full_table_name = isnull(quotename(@table_owner), '') + '.' + isnull(quotename(@table_name), '') 
    select @table_id = object_id(@full_table_name) 

    if (@fUsePattern = 1) -- Does the user want it? 
    begin 
     if ((isnull(charindex('%', @full_table_name),0) = 0) and 
      (isnull(charindex('_', @full_table_name),0) = 0) and 
      (isnull(charindex('[', @table_name),0) = 0) and 
      (isnull(charindex('[', @table_owner),0) = 0) and 
      (isnull(charindex('%', @column_name),0) = 0) and 
      (isnull(charindex('_', @column_name),0) = 0) and 
      (@table_id <> 0)) 
     begin 
      select @fUsePattern = 0 -- not a single wild char, so go the fast way. 
     end 
    end 

    if @fUsePattern = 0 
    begin 
     /* -- Debug output, do not remove it. 
     print '*************' 
     print 'No pattern matching.' 
     print @fUsePattern 
     print isnull(convert(sysname, @table_id), '@table_id = null') 
     print isnull(@full_table_name, '@full_table_name = null') 
     print isnull(@table_owner, '@table_owner = null') 
     print isnull(@table_name, '@table_name = null') 
     print isnull(@column_name, '@column_name = null') 
     print '*************' 
     */ 
     select 
      TABLE_QUALIFIER    = s_cov.TABLE_QUALIFIER, 
      TABLE_OWNER     = s_cov.TABLE_OWNER, 
      TABLE_NAME     = s_cov.TABLE_NAME, 
      COLUMN_NAME     = s_cov.COLUMN_NAME, 
      DATA_TYPE     = s_cov.DATA_TYPE_28, 
      TYPE_NAME     = s_cov.TYPE_NAME_28, 
      "PRECISION"     = s_cov.PRECISION_28, 
      "LENGTH"     = s_cov.LENGTH_28, 
      SCALE      = s_cov.SCALE_90, 
      RADIX      = s_cov.RADIX, 
      NULLABLE     = s_cov.NULLABLE, 
      REMARKS      = s_cov.REMARKS, 
      COLUMN_DEF     = s_cov.COLUMN_DEF, 
      SQL_DATA_TYPE    = s_cov.SQL_DATA_TYPE_28, 
      SQL_DATETIME_SUB   = s_cov.SQL_DATETIME_SUB_90, 
      CHAR_OCTET_LENGTH   = s_cov.CHAR_OCTET_LENGTH_28, 
      ORDINAL_POSITION   = s_cov.ORDINAL_POSITION, 
      IS_NULLABLE     = s_cov.IS_NULLABLE, 
      SS_DATA_TYPE    = s_cov.SS_DATA_TYPE 

     from 
      sys.spt_columns_odbc_view s_cov 

     where 
      s_cov.object_id = @table_id -- (2nd) (@table_name is null or o.name like @table_name) 
      -- (2nd) and (@table_owner is null or schema_name(o.schema_id) like @table_owner) 
      and (@column_name is null or s_cov.COLUMN_NAME = @column_name) -- (2nd)    and (@column_name is NULL or c.name like @column_name) 
      and s_cov.ODBCVER = @ODBCVer 
      and s_cov.OBJECT_TYPE <> 'TT' 
      and (s_cov.SS_IS_SPARSE = 0 OR objectproperty (s_cov.OBJECT_ID, 'tablehascolumnset') = 0) 
     order by 17 
    end 
    else 
    begin 
     /* -- Debug output, do not remove it. 
     print '*************' 
     print 'THERE IS pattern matching!' 
     print @fUsePattern 
     print isnull(convert(sysname, @table_id), '@table_id = null') 
     print isnull(@full_table_name, '@full_table_name = null') 
     print isnull(@table_owner, '@table_owner = null') 
     print isnull(@table_name, '@table_name = null') 
     print isnull(@column_name, '@column_name = null') 
     print '*************' 
    */ 
     select 
      TABLE_QUALIFIER    = s_cov.TABLE_QUALIFIER, 
      TABLE_OWNER     = s_cov.TABLE_OWNER, 
      TABLE_NAME     = s_cov.TABLE_NAME, 
      COLUMN_NAME     = s_cov.COLUMN_NAME, 
      DATA_TYPE     = s_cov.DATA_TYPE_28, 
      TYPE_NAME     = s_cov.TYPE_NAME_28, 
      "PRECISION"     = s_cov.PRECISION_28, 
      "LENGTH"     = s_cov.LENGTH_28, 
      SCALE      = s_cov.SCALE_90, 
      RADIX      = s_cov.RADIX, 
      NULLABLE     = s_cov.NULLABLE, 
      REMARKS      = s_cov.REMARKS, 
      COLUMN_DEF     = s_cov.COLUMN_DEF, 
      SQL_DATA_TYPE    = s_cov.SQL_DATA_TYPE_28, 
      SQL_DATETIME_SUB   = s_cov.SQL_DATETIME_SUB_90, 
      CHAR_OCTET_LENGTH   = s_cov.CHAR_OCTET_LENGTH_28, 
      ORDINAL_POSITION   = s_cov.ORDINAL_POSITION, 
      IS_NULLABLE     = s_cov.IS_NULLABLE, 
      SS_DATA_TYPE    = s_cov.SS_DATA_TYPE 

     from 
      sys.spt_columns_odbc_view s_cov 

     where 
      s_cov.ODBCVER = @ODBCVer and 
      s_cov.OBJECT_TYPE <> 'TT' and 
      (@table_name is null or s_cov.TABLE_NAME like @table_name) and 
      (@table_owner is null or schema_name(s_cov.SCHEMA_ID) like @table_owner) and 
      (@column_name is null or s_cov.COLUMN_NAME like @column_name) and 
      (s_cov.SS_IS_SPARSE = 0 OR objectproperty (s_cov.OBJECT_ID, 'tablehascolumnset') = 0) 

     order by 2, 3, 17 
    end 

現在你可以決定是否有「任何毒副作用表「