Question

我编写了一个过程来将视图内容提取到Oracle中的文件系统。现在客户端想要测试文件的内容。我如何在Oracle中以通用方式执行此操作？

步骤：

CREATE OR REPLACE PROCEDURE PRC_EXTRACT_VIEW (p_view_name VARCHAR2, p_timestamp VARCHAR2)
   AUTHID CURRENT_USER
IS
/* Run:
    set serveroutput on timing on
    begin PRC_EXTRACT_VIEW('V_TEST'); end;
*/
    p_query      VARCHAR2(512) :='SELECT * FROM '||p_view_name;
    p_separator  VARCHAR2(8) := '';
    p_dir_obj    VARCHAR2(126) :='TEST_DIR';
    p_filename   VARCHAR2(128) :=p_view_name||'_'||p_timestamp||'.csv'; 

  l_output utl_file.file_type;
  l_cnt         NUMBER := 0;
  l_theCursor   INTEGER DEFAULT dbms_sql.open_cursor;
  l_columnValue VARCHAR2(2000):='';

  l_status      INTEGER;  
  l_separator   VARCHAR2(10) DEFAULT '';
  c           NUMBER;
  d           NUMBER;
  col_cnt     INTEGER;
  f           BOOLEAN;
  rec_tab     DBMS_SQL.DESC_TAB;
  col_num    NUMBER;
  v_sql dbms_sql.varchar2a;
  v_sql_1 varchar2(32767); 
  pn varchar2(32):='PRC_EXTRACT_VIEW';
v_ErrMsg varchar2(2000);
v_Errcode varchar2(60);
v_etl_btch_id number;  
v_filename varchar2(256):=p_filename;

BEGIN

      l_output := utl_file.fopen( p_dir_obj, v_filename, 'w',32767 );
      DBMS_SQL.PARSE(l_theCursor, p_query, DBMS_SQL.NATIVE);
      FOR i IN 1 .. 255
      LOOP
        BEGIN
          dbms_sql.define_column( l_theCursor, i, l_columnValue, 2000 );
        EXCEPTION
        WHEN OTHERS THEN
          IF ( SQLCODE = -1007 ) THEN
            EXIT;
          ELSE
            raise;
          END IF;
        END;
      END LOOP;
    dbms_sql.define_column( l_theCursor, 1, l_columnValue, 2000 );
      d := DBMS_SQL.EXECUTE(l_theCursor);
      DBMS_SQL.DESCRIBE_COLUMNS(l_theCursor, col_cnt, rec_tab);
    LOOP
      EXIT
    WHEN ( dbms_sql.fetch_rows(l_theCursor) <= 0 );
    l_separator                           := '';
      FOR i IN 1 .. col_cnt
      LOOP
        dbms_sql.column_value( l_theCursor, i, l_columnValue );
        --dbms_output.put_line(l_columnValue);    
        utl_file.put( l_output, l_separator || l_columnValue );
        l_separator := p_separator;
      END LOOP;

     utl_file.new_line( l_output );
      l_cnt := l_cnt+1;
    END LOOP;
    dbms_sql.close_cursor(l_theCursor);
    utl_file.fclose( l_output );

/*--TODO
EXCEPTION
WHEN OTHERS THEN 
  */
END PRC_EXTRACT_VIEW;
/

客户端对于文件中的内容很有用。有没有办法在同一会话或新会话中读取转储文件的内容？（用于测试目的）

Answer 1

您可以根据用于假脱机的视图生成外部表。

对于相同的p_view_name，您只需执行一次，然后即使p_timestamp更改了新提取，您也可以更改现有的永久表：

alter table ext_table location ('new_filename');

如果p_view_name发生更改，则必须重新运行表生成脚本。

我提供的解决方案仅在数据文件中的每一列都具有所有行的固定长度时才有效。

首先，您必须生成“列列表视图” - 包含所有已声明的列名称和源视图长度的展平结构。

/* Execute:
sqlplus scott/tiger@orcl1 @gen_column_list_view_ddl.sql
*/
SET SQLBLANKLINES ON 
SET PAGESIZE 0 FEEDBACK OFF 
SET TRIMSPOOL ON LINE 32000 
SET WRAP ON
SET NEWPAGE NONE
SET PAGESIZE 0
SET SPACE 0 LONG 1000
SET ECHO OFF
SET FEEDBACK OFF
SET VERIFY OFF
SET HEADING OFF
set termout off

spool GENERATE_EXTERNAL_TABLE/GENERATED/v_column_list.sql
PROMPT set sqlblanklines on
select  '
create or replace view v_column_list
  as select ' from dual
union all
select ''''||column_name||''' '||column_name||', length('||column_name||') "'||column_name||'_len"'||(case cid when max_cid then '' else ',' end) len 
from 
 (select column_id cid, max(column_id)  over() max_cid,column_name 
  from all_tab_columns 
  where table_name=:source_view order by column_id) 
union all
select ' 
from  '||:source_view||' 
where rownum <2' from dual;
PROMPT /
--PROMPT exit;;
spool off

因为你没有分隔符提取它意味着它是固定长度的，并且实际数据大小对于给定列的所有行都是相同的。

第二步是“列长度视图”生成。因为给定列的声明数据长度可能与实际数据长度不同，所以我们必须创建另一个视图来修复它。

/* Execute:
sqlplus scott/tiger@orcl1 @gen_col_len_view_ddl.sql
*/
SET SQLBLANKLINES ON HEAD OFF 
SET PAGESIZE 0 FEEDBACK OFF 
SET TRIMSPOOL ON LINE 32000 
SET WRAP ON
SET NEWPAGE NONE
SET PAGESIZE 0
SET SPACE 0 LONG 1000
SET ECHO OFF
SET FEEDBACK OFF
SET VERIFY OFF
SET HEADING OFF
set termout off

spool GENERATE_EXTERNAL_TABLE/GENERATED/v_col_len.sql
PROMPT set sqlblanklines on
select  '
create or replace view v_col_len as 
  select rn1,col_name,col_len 
    from( select rownum rn1,value col_name 
            from (select *  from v_column_list 
              unpivot (  value     
                      for value_type  in (' str 
from dual
union all
select '"'||column_name||'"'||(case cid when max_cid then '' else ',' end) len 
from 
 (select column_id cid, max(column_id)  over() max_cid,column_name 
  from all_tab_columns 
  where table_name=:source_view 
  order by column_id) 
union all
select ') 
  ))),
  (select rownum rn2, value col_len 
     from ( select *  from v_column_list 
        unpivot (  value  for value_type  in (' 
from dual
union all    
select '"'||column_name||'_len"'||(case cid when max_cid then '' else ',' end) len 
from 
 (select column_id cid, max(column_id)  over() max_cid,column_name 
  from all_tab_columns 
  where table_name=:source_view 
  order by column_id)
union all
select    ') 
  ))) 
    where rn1=rn2 ' from dual;
PROMPT /
--PROMPT exit;;

spool off

现在我们知道一列结束的位置和另一列的开始，我们可以生成外部表DDL

/* Execute:
sqlplus scott/tiger@orcl1 @gen_external_table_ddl.sql
*/
COLUMN str format a900
set termout on
PROMPT Generating ext table DDL
set termout off
SET SQLBLANKLINES ON 
SET PAGESIZE 0 
SET TRIMSPOOL ON LINE 32000 
SET WRAP ON
SET NEWPAGE NONE
SET PAGESIZE 0
SET SPACE 0
SET LINESIZE 16000
SET ECHO OFF
SET FEEDBACK OFF
SET VERIFY OFF
SET HEADING OFF
set timing off
set time off
set headsep off
set termout off

spool GENERATE_EXTERNAL_TABLE/GENERATED/fixed_width_external_table.sql
PROMPT set sqlblanklines on
PROMPT set termout on
PROMPT PROMPT Creating external table  

WITH c as (select * from V_COL_LEN) 
select 'DROP TABLE '||:ext_table_name||';' str from dual
union all
select ' 
set termout off
CREATE TABLE '||:ext_table_name||'   
  ( '  
  str 
  from dual union all
select  col_name||' CHAR('||col_len||')'||(case rn1 when max_rn then '' else ',' end) str from 
(
select  col_name,col_len, rn1, max(rn1) over() max_rn
 from c)
 union all 
 select '  )
  ORGANIZATION external
  (
    TYPE oracle_loader
    DEFAULT DIRECTORY TEST_DIR
    ACCESS PARAMETERS
    (
      RECORDS DELIMITED BY NEWLINE CHARACTERSET WE8ISO8859P1
      READSIZE 1048576
      FIELDS LDRTRIM
      MISSING FIELD VALUES ARE NULL
      REJECT ROWS WITH ALL NULL FIELDS
      (' 
from dual
union all
select  col_name||' ('||(CUMTOT-col_len+1)||':'||CUMTOT||') CHAR('||col_len||')'||(case rn1 when max_rn then '' else ',' end) str from (
select col_name,col_len,
 SUM(col_len) OVER (ORDER BY rn1) CUMTOT, rn1, max(rn1) over() max_rn
 from c)
union all
select ')
    )
    location
    (
     '''||:dump_file_name||'''
   )
 )
' 
 from dual
/
PROMPT /
--PROMPT exit;;
spool off

要将其包装起来，您可以创建执行所有3个步骤的独立脚本。

var dump_file_name varchar2(128);
BEGIN
  select 'c_'||export_date||'.dmp' into  :dump_file_name
  from  (select  
  to_char(sd,'MM')||to_char(sd,'YY')  export_date
  from (SELECT systimestamp sd FROM DUAL));
END;
/



print :dump_file_name

var ext_table_name varchar2(32);
BEGIN
select 'fixed_width_external_table'  into :ext_table_name from dual;
END;
/

print :ext_table_name


var source_view varchar2(32);
BEGIN
select 'V_TEST'  into :source_view from dual;
END;
/

print :source_view







PROMPT Generating column list view (V_COLUMN_LIST) based on source view
@GENERATE_EXTERNAL_TABLE/gen_column_list_view_ddl.sql
@GENERATE_EXTERNAL_TABLE/GENERATED/v_column_list.sql

PROMPT Generating column lengths view (V_COL_LEN) based on source view
@GENERATE_EXTERNAL_TABLE/gen_col_len_view_ddl.sql
@GENERATE_EXTERNAL_TABLE/GENERATED/v_col_len.sql

PROMPT Generating external table DDL based on V_COL_LEN
@GENERATE_EXTERNAL_TABLE/gen_external_table_ddl.sql
@GENERATE_EXTERNAL_TABLE/GENERATED/fixed_width_external_table.sql

SET PAGESIZE 99
SET ECHO on
SET FEEDBACK on
SET VERIFY OFF
SET HEADING on
set timing on
set time on
set headsep on
set termout on

var exported_cnt varchar2(32);
BEGIN
EXECUTE IMMEDIATE 'select /*+PARALLEL (t,auto)*/ count(*) rows_exported from '||:ext_table_name||' t' INTO :exported_cnt;
END;
/

print :exported_cnt

此脚本将从Oracle中的现有视图或堆表名创建外部表DDL。

我最初在Oracle中编写if for regular to external table conversion。

我在Oracle中使用UTL_FILE创建了CSV文件。我怎么读回来？

1 个答案: