Question

Oracle 11g肯定提高了CLOB的可用性，使大多数字符串函数重载，因此它们现在可以在CLOB中本地工作。

然而，一位同事从他的代码中得到了这个错误：

ORA-22828: input pattern or replacement parameters exceed 32K size limit
22828. 00000 -  "input pattern or replacement parameters exceed 32K size limit"
*Cause:    Value provided for the pattern or replacement string in the form of
           VARCHAR2 or CLOB for LOB SQL functions exceeded the 32K size limit.
*Action:   Use a shorter pattern or process a long pattern string in multiple
           passes.

仅当replace的第三个参数是一个超过32k字符的CLOB时才会发生这种情况。

（Oracle Database 11g企业版11.2.0.3.0版 - 64位生产版）

测试用例：

declare
  v2 varchar2(32767);
  cl_small clob;
  cl_big clob;
  cl_big2 clob;
begin
  v2 := rpad('x', 32767, 'x');
  dbms_output.put_line('v2:' || length(v2));
  cl_small := v2;
  dbms_output.put_line('cl_small:' || length(cl_small));
  cl_big := v2 || 'y' || v2;
  dbms_output.put_line('cl_big[1]:' || length(cl_big));
  cl_big2 := replace(cl_big, 'y', cl_small);
  dbms_output.put_line('cl_big[2]:' || length(cl_big2));
  cl_big2 := replace(cl_big, 'y', cl_big); 
  dbms_output.put_line('cl_big[3]:' || length(cl_big2));
end;
/

结果：

v2:32767
cl_small:32767
cl_big[1]:65535
cl_big[2]:98301
ORA-22828: input pattern or replacement parameters exceed 32K size limit

这似乎与暗示替换字符串可能是CLOB的文档不一致 - 我本以为应该暗示任何CLOB都会被允许，而不仅仅是那些恰好是＆lt; ; 32K：http://docs.oracle.com/cd/E11882_01/server.112/e41084/functions153.htm#SQLRF00697

Answer 1

这是一个功能粗略的初稿，它将在某些限制下完成工作，但尚未经过很好的测试：

function replace_with_clob
  (i_source in clob
  ,i_search in varchar2
  ,i_replace in clob
  ) return clob is
  l_pos pls_integer;
begin
  l_pos := instr(i_source, i_search);
  if l_pos > 0 then
    return substr(i_source, 1, l_pos-1)
        || i_replace
        || substr(i_source, l_pos+length(i_search));
  end if;
  return i_source;
end replace_with_clob;

它只对搜索词的第一个实例进行一次替换。

declare
  v2 varchar2(32767);
  cl_small clob;
  cl_big clob;
  cl_big2 clob;
begin
  v2 := rpad('x', 32767, 'x');
  dbms_output.put_line('v2:' || length(v2));
  cl_small := v2;
  dbms_output.put_line('cl_small:' || length(cl_small));
  cl_big := v2 || 'y' || v2;
  dbms_output.put_line('cl_big[1]:' || length(cl_big));
  cl_big2 := replace(cl_big, 'y', cl_small);
  dbms_output.put_line('cl_big[2]:' || length(cl_big2));
  cl_big2 := replace_with_clob(cl_big, 'y', cl_big); 
  dbms_output.put_line('cl_big[3]:' || length(cl_big2));
end;
/

v2:32767
cl_small:32767
cl_big[1]:65535
cl_big[2]:98301
cl_big[3]:131069

Answer 2

您可以创建一个函数来处理任意长度的CLOB值：

SQL Fiddle

CREATE FUNCTION lob_replace(
  i_lob    IN clob, 
  i_what   IN varchar2, 
  i_with   IN clob,
  i_offset IN INTEGER DEFAULT 1,
  i_nth    IN INTEGER DEFAULT 1
) RETURN CLOB
AS
  o_lob  CLOB;
  n      PLS_INTEGER;
  l_lob  PLS_INTEGER;
  l_what PLS_INTEGER;
  l_with PLS_INTEGER;
BEGIN
  IF   i_lob IS NULL
    OR i_what IS NULL
    OR i_offset < 1
    OR i_offset > DBMS_LOB.LOBMAXSIZE
    OR i_nth < 1
    OR i_nth > DBMS_LOB.LOBMAXSIZE
  THEN
    RETURN NULL;
  END IF;

  n      := NVL( DBMS_LOB.INSTR( i_lob, i_what, i_offset, i_nth ), 0 );
  l_lob  := DBMS_LOB.GETLENGTH( i_lob );
  l_what := LENGTH( i_what );
  l_with := NVL( DBMS_LOB.GETLENGTH( i_with ), 0 );

  DBMS_LOB.CREATETEMPORARY( o_lob, FALSE );
  IF n > 0 THEN
    IF n > 1 THEN
      DBMS_LOB.COPY( o_lob, i_lob, n-1, 1, 1 );
    END IF;

    IF l_with > 0 THEN
      DBMS_LOB.APPEND( o_lob, i_with ); 
    END IF;

    IF n + l_what <= l_lob THEN
      DBMS_LOB.COPY( o_lob, i_lob, l_lob - n - l_what + 1, n + l_with, n + l_what );
    END IF;
  ELSE
    DBMS_LOB.APPEND( o_lob, i_lob );
  END IF;
  RETURN o_lob;
END; 
/

Oracle 11g R2架构设置：

CREATE TABLE table_name ( value clob)
/

CREATE TABLE replacements ( str VARCHAR2(4000), repl CLOB )
/

DECLARE
  str VARCHAR2(4000) := 'value';
  r   CLOB;
  c1l CLOB;
  c1m CLOB;
  c1r CLOB;
  c2l CLOB;
  c2m CLOB;
  c2r CLOB;
  c3l CLOB;
  c3m CLOB;
  c3r CLOB;
BEGIN
  DBMS_LOB.CREATETEMPORARY( r, FALSE );
  DBMS_LOB.CREATETEMPORARY( c1l, FALSE );
  DBMS_LOB.CREATETEMPORARY( c1m, FALSE );
  DBMS_LOB.CREATETEMPORARY( c1r, FALSE );
  DBMS_LOB.CREATETEMPORARY( c2l, FALSE );
  DBMS_LOB.CREATETEMPORARY( c2m, FALSE );
  DBMS_LOB.CREATETEMPORARY( c2r, FALSE );
  DBMS_LOB.CREATETEMPORARY( c3l, FALSE );
  DBMS_LOB.CREATETEMPORARY( c3m, FALSE );
  DBMS_LOB.CREATETEMPORARY( c3r, FALSE );
  FOR i IN 1 .. 10 LOOP
    DBMS_LOB.WRITEAPPEND( r, 4000, RPAD( 'y', 4000, 'y' ) );
    DBMS_LOB.WRITEAPPEND( C1m, 20, RPAD( 'x', 20, 'x' ) );
    DBMS_LOB.WRITEAPPEND( C1r, 40, RPAD( 'x', 40, 'x' ) );
    DBMS_LOB.WRITEAPPEND( C2m, 200, RPAD( 'x', 200, 'x' ) );
    DBMS_LOB.WRITEAPPEND( C2r, 400, RPAD( 'x', 400, 'x' ) );
    DBMS_LOB.WRITEAPPEND( C3m, 2000, RPAD( 'x', 2000, 'x' ) );
    DBMS_LOB.WRITEAPPEND( C3r, 4000, RPAD( 'x', 4000, 'x' ) );
  END LOOP;
  DBMS_LOB.WRITEAPPEND( c1l, 5, str );
  DBMS_LOB.WRITEAPPEND( c1m, 5, str );
  DBMS_LOB.WRITEAPPEND( c1r, 5, str );
  DBMS_LOB.WRITEAPPEND( c2l, 5, str );
  DBMS_LOB.WRITEAPPEND( c2m, 5, str );
  DBMS_LOB.WRITEAPPEND( c2r, 5, str );
  DBMS_LOB.WRITEAPPEND( c3l, 5, str );
  DBMS_LOB.WRITEAPPEND( c3m, 5, str );
  DBMS_LOB.WRITEAPPEND( c3r, 5, str );
  FOR i IN 1 .. 10 LOOP
    DBMS_LOB.WRITEAPPEND( C1l, 40, RPAD( 'x', 40, 'x' ) );
    DBMS_LOB.WRITEAPPEND( C1m, 20, RPAD( 'x', 20, 'x' ) );
    DBMS_LOB.WRITEAPPEND( C2l, 400, RPAD( 'x', 400, 'x' ) );
    DBMS_LOB.WRITEAPPEND( C2m, 200, RPAD( 'x', 200, 'x' ) );
    DBMS_LOB.WRITEAPPEND( C3l, 4000, RPAD( 'x', 4000, 'x' ) );
    DBMS_LOB.WRITEAPPEND( C3m, 2000, RPAD( 'x', 2000, 'x' ) );
  END LOOP;
  INSERT INTO table_name VALUES ( NULL );
  INSERT INTO table_name VALUES ( EMPTY_CLOB() );
  INSERT INTO table_name VALUES ( '0123456789' );
  INSERT INTO table_name VALUES ( str );
  INSERT INTO table_name VALUES ( c1l );
  INSERT INTO table_name VALUES ( c1m );
  INSERT INTO table_name VALUES ( c1r );
  INSERT INTO table_name VALUES ( c2l );
  INSERT INTO table_name VALUES ( c2m );
  INSERT INTO table_name VALUES ( c2r );
  INSERT INTO table_name VALUES ( c3l );
  INSERT INTO table_name VALUES ( c3m );
  INSERT INTO table_name VALUES ( c3r );
  INSERT INTO replacements VALUES ( str, r );
  COMMIT;
END;
/

查询1 ：

SELECT DBMS_LOB.GETLENGTH( value )
FROM   table_name

<强> Results ：

| DBMS_LOB.GETLENGTH(VALUE) |
|---------------------------|
|                    (null) |
|                         0 |
|                        10 |
|                         5 |
|                       405 |
|                       405 |
|                       405 |
|                      4005 |
|                      4005 |
|                      4005 |
|                     40005 |
|                     40005 |
|                     40005 |

查询2 ：

UPDATE table_name
SET value = LOB_REPLACE(
              value,
              ( SELECT str FROM replacements ),
              ( SELECT repl FROM replacements )
            )

查询3 ：

SELECT DBMS_LOB.GETLENGTH( value )
FROM   table_name

<强> Results ：

| DBMS_LOB.GETLENGTH(VALUE) |
|---------------------------|
|                    (null) |
|                         0 |
|                        10 |
|                     40000 |
|                     40400 |
|                     40400 |
|                     40400 |
|                     44000 |
|                     44000 |
|                     44000 |
|                     80000 |
|                     80000 |
|                     80000 |

Answer 3

这将完成这项工作：

function CLOBREPLACE(
  AINPUT      CLOB,
  APATTERN    VARCHAR2,
  ASUBSTITUTE CLOB
) return CLOB is
FCLOB   CLOB := AINPUT;
FOFFSET INTEGER;
FCHUNK  CLOB;
begin
  if length(ASUBSTITUTE) > 32000 then
    FOFFSET := 1;
    FCLOB := replace(FCLOB, APATTERN, '###CLOBREPLACE###');
    while FOFFSET <= length(ASUBSTITUTE) loop
      FCHUNK := substr(ASUBSTITUTE, FOFFSET, 32000) || '###CLOBREPLACE###';
      FCLOB := regexp_replace(FCLOB, '###CLOBREPLACE###', FCHUNK);
      FOFFSET := FOFFSET + 32000;
    end loop;
    FCLOB := regexp_replace(FCLOB, '###CLOBREPLACE###', '');
  else 
    FCLOB := replace(FCLOB, APATTERN, ASUBSTITUTE);
  end if;
  return FCLOB;
end;

测试用例的结果：

v2:32767
cl_small:32767
cl_big[1]:65535
cl_big[2]:98301
cl_big[3]:131069

Answer 4

函数REPLACE可用于CLOB

文档： http://psoug.org/reference/translate_replace.html

工作样本：

declare
  l_clob clob;
  l_parname clob;
  l_value  clob;
  l_par_id_obj        varchar2(200) := '${id_obj}';

  procedure setCLOBValue(p_CLOB in out CLOB, p_value string) as
  begin
    DBMS_LOB.createtemporary(p_CLOB, false);
    dbms_lob.open(p_CLOB, dbms_lob.lob_readwrite);
    dbms_lob.write(p_CLOB, length(p_value), 1, p_value);
    dbms_lob.close(p_CLOB);
  end;

begin
  select SOURCE_FILE into l_clob from st_static_source_clob;

  setCLOBValue(l_parname, l_par_id_obj);
  setCLOBValue(l_value, '200701000024');

  l_clob := replace(l_clob, l_parname, l_value);

end;

Answer 5

以下功能解决了这个问题：

create or replace FUNCTION replace_clob
(
  in_source  IN CLOB,
  in_search  IN VARCHAR2,
  in_replace IN CLOB
) 
RETURN CLOB 
IS
  l_pos pls_integer;
  out_replace_clob CLOB := in_source;
BEGIN
  l_pos := instr(in_source, in_search);

  IF l_pos > 0 THEN
  WHILE l_pos > 0 LOOP
    out_replace_clob := substr(out_replace_clob, 1, l_pos-1)
        || in_replace
        || substr(out_replace_clob, l_pos+LENGTH(in_search));
  l_pos := instr(out_replace_clob, in_search);
  END LOOP;
  RETURN out_replace_clob;
  END IF;

  RETURN in_source;
END replace_clob;
/

Answer 6

下面的这个函数替换了 Oracle PLSQL 中 CLOB 数据类型的所有功能

CREATE FUNCTION lob_replaceall
(
  i_lob    IN clob, 
  i_what   IN varchar2, 
  i_with   IN clob,
  i_offset IN INTEGER DEFAULT 1
) RETURN CLOB
AS
  o_lob  CLOB;
  n      PLS_INTEGER;
  l_lob  PLS_INTEGER;
  l_what PLS_INTEGER;
  l_with PLS_INTEGER;
  l_temp_lob CLOB;
BEGIN
  IF   i_lob IS NULL
    OR i_what IS NULL
    OR i_offset < 1
    OR i_offset > DBMS_LOB.LOBMAXSIZE
  THEN
    RETURN NULL;
  END IF;
  l_temp_lob:=i_lob;
  LOOP 
  n      := NVL( DBMS_LOB.INSTR( l_temp_lob, i_what, i_offset, 1 ), 0 );
  l_lob  := DBMS_LOB.GETLENGTH( l_temp_lob );
  l_what := LENGTH( i_what );
  l_with := NVL( DBMS_LOB.GETLENGTH( i_with ), 0 );

  DBMS_LOB.CREATETEMPORARY( o_lob, FALSE );
  IF n > 0 THEN
    IF n > 1 THEN
      DBMS_LOB.COPY( o_lob, l_temp_lob, n-1, 1, 1 );
    END IF;

    IF l_with > 0 THEN
      DBMS_LOB.APPEND( o_lob, i_with ); 
    END IF;

    IF n + l_what <= l_lob THEN
      DBMS_LOB.COPY( o_lob, l_temp_lob, l_lob - n - l_what + 1, n + l_with, n + l_what );
    END IF;
  ELSE
    DBMS_LOB.APPEND( o_lob, l_temp_lob );
  END IF;
  EXIT WHEN n=0;
  l_temp_lob:= o_lob;
  o_lob := NULL;
 END LOOP;
  RETURN o_lob;
END; 
/

如何用CLOB调用REPLACE（不超过32K）

6 个答案: