使用 SAS Data Integration (DI) Studio 开发 ETL 程序时,您指定的每个转换都有一个简洁的用户界面来指定您创建的数据集(=表)的列及其类型、长度和格式。
当现有的转换无法完成工作并且需要用户编写代码时,您应该尽可能使用点击式界面,因为
- 它支持影响分析和反向影响分析
- 您的继任者可能不会深入研究 SAS 基本代码,除非他们真的需要
- 如果他们需要更改列或格式,他们希望更改用户界面中的规范就可以完成这项工作
幸运的是,SAS 向程序员公开了用户在宏变量中编写的转换的输出格式
所以我经常把我的代码写在用户写的转换里面
%macro format_output(data);
%do _col = 0 %to &&&data._col_count - 1;
length &&&data._col&_col._name &&&data._col&_col._type&&&data._col&_col._length;
%if %length(&&&data._col&_col._format) %then %do;
format &&&data._col&_col._name &&&data._col&_col._format;
%end;
%end;
%mend;
data &_OUTPUT1 (keep=&_OUTPUT1_keep);
%format_output(_OUTPUT1);
set &_INPUT1;
* actua code ;
run;
SAS 是否提供嵌入式宏或其他东西来做同样的事情?
为了完整性:SAS公开输出结构的方式看起来像
%let _OUTPUT1 = myLib.myTable;
%let _OUTPUT1_connect = ;
%let _OUTPUT1_engine = ;
%let _OUTPUT1_memtype = DATA;
%let _OUTPUT1_options = %nrquote();
%let _OUTPUT1_alter = %nrquote();
%let _OUTPUT1_path = %nrquote(/myTable_A5E5JYT6.C7000MOL%(WorkTable%));
%let _OUTPUT1_type = 1;
%let _OUTPUT1_label = %nrquote();
/* List of target columns to keep */
%let _OUTPUT1_keep = myID first_item <16 more items> last_item;
%let _OUTPUT1_col_count = 19;
%let _OUTPUT1_col0_name = myID;
%let _OUTPUT1_col0_table = myLib.myTable;
%let _OUTPUT1_col0_length = 8;
%let _OUTPUT1_col0_type = ;
%let _OUTPUT1_col0_format = 13.;
%let _OUTPUT1_col0_informat = 13.;
%let _OUTPUT1_col0_label = %nrquote(my ID);
%let _OUTPUT1_col0_input0 = myID;
%let _OUTPUT1_col0_exp = ;
%let _OUTPUT1_col0_input = myID;
%let _OUTPUT1_col0_input_count = 1;
%let _OUTPUT1_col1_name = first_item;
%let _OUTPUT1_col1_table = myLib.myTable;
%let _OUTPUT1_col1_length = 8;
%let _OUTPUT1_col1_type = $;
%let _OUTPUT1_col1_format = $CHAR8.;
%let _OUTPUT1_col1_informat = $CHAR8.;
%let _OUTPUT1_col1_label = %nrquote(first data item in my table);
%let _OUTPUT1_col1_input0 = first_item;
%let _OUTPUT1_col1_exp = ;
%let _OUTPUT1_col1_input = first_item;
%let _OUTPUT1_col1_input_count = 1;
<documentation about 16 more columns>
%let _OUTPUT1_col18_name = last_item;
%let _OUTPUT1_col18_table = myLib.myTable;
%let _OUTPUT1_col18_length = 16;
%let _OUTPUT1_col18_type = $;
%let _OUTPUT1_col18_format = $16.;
%let _OUTPUT1_col18_informat = $16.;
%let _OUTPUT1_col18_label = %nrquote(last data item in my table);
%let _OUTPUT1_col18_input0 = last_item;
%let _OUTPUT1_col18_exp = ;
%let _OUTPUT1_col18_input = last_item;
%let _OUTPUT1_col18_input_count = 1;
%let _OUTPUT1_filetype = WorkTable;