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oracle-databasereplacepattern-matchingregexp-replace

How to retain the same case in the text in Oracle?


I have a table with columns word and sentence. The idea is to replace the words in the sentence with the link(includes the word itself) if the word is found in the word column. The query below replaces perfectly but since the link is constructed from the temp.word column, the case of the words in the sentence is changed to the case of the words in the word column. Is there a way to retain the same case in the sentence itself?

Create table temp(
  id       NUMBER,
  word     VARCHAR2(1000),
  sentence VARCHAR2(2000)
);

insert into temp
SELECT 1,'automation testing', 'automtestingation Testing is popular kind of testing' FROM DUAL UNION ALL
SELECT 2,'testing','manual testing' FROM DUAL UNION ALL
SELECT 3,'manual testing','this is an old method of testing' FROM DUAL UNION ALL
SELECT 4,'punctuation','automation testing,manual testing,punctuation,automanual testing-testing' FROM DUAL UNION ALL
SELECT 5,'B-number analysis','B-number analysis table' FROM DUAL UNION ALL
SELECT 6,'B-number analysis table','testing B-number analysis' FROM DUAL UNION ALL
SELECT 7,'Not Matched','testing testing testing' FROM DUAL;

with words(id, word, word_length, search1, replace1, search2, replace2) as (
  select id, word, length(word),
  '(^|\W)' || REGEXP_REPLACE(word, '([][)(}{|^$\.*+?])', '\\\1') || '($|\W)',
  '\1{'|| id ||'}\2',
  '{'|| id ||'}',
  'http://localhost/' || id || '/<u>' || word || '</u>'
  FROM temp
)
, joined_data as (
  select w.search1, w.replace1, w.search2, w.replace2,
    s.rowid s_rid, s.sentence,
    row_number() over(partition by s.rowid order by word_length desc) rn
  from words w
  join temp s
  on instr(UPPER(s.sentence), UPPER(w.word)) > 0
  and regexp_like(s.sentence, w.search1)
)
, unpivoted_data as (
  select S_RID, SENTENCE, PHASE, SEARCH_STRING, REPLACE_STRING,
    row_number() over(partition by s_rid order by phase, rn) rn,
    case when row_number() over(partition by s_rid order by phase, rn)
      = count(*) over(partition by s_rid)
      then 1
      else 0
    end is_last
  from joined_data
  unpivot(
    (search_string, replace_string) 
    for phase in ( (search1, replace1) as 1, (search2, replace2) as 2 ))
)
, replaced_data(S_RID, RN, is_last, SENTENCE) as (
  select S_RID, RN, is_last,
    regexp_replace(SENTENCE, search_string, replace_string,1,0,'i')
  from unpivoted_data
  where rn = 1
  union all
  select n.S_RID, n.RN, n.is_last,
    case when n.phase = 1
      then regexp_replace(o.SENTENCE, n.search_string, n.replace_string,1,0,'i')
      else replace(o.SENTENCE, n.search_string, n.replace_string)
    end
  from unpivoted_data n
  join replaced_data o
    on o.s_rid = n.s_rid and n.rn = o.rn + 1  
)
select s_rid, sentence from replaced_data
where is_last = 1
order by s_rid;

For example, for id = 1, the sentence is automtestingation Testing is popular kind of testing
After replacement it will be automtestingation http://localhost/2/<u>testing</u> is popular kind of http://localhost/2/<u>testing</u>.

The word Testing is replaced with testing(from the temp.word column).

The expected outcome is

automtestingation http://localhost/2/<u>Testing</u> is popular kind of http://localhost/2/<u>testing</u>

Solution

  • Oracle Setup:

    Create table temp(
      id       NUMBER,
      word     VARCHAR2(1000),
      Sentence VARCHAR2(2000)
    );
    
    insert into temp
    SELECT 1,'automation testing', 'automtestingation TeStInG TEST is popular kind of testing' FROM DUAL UNION ALL
    SELECT 2,'testing','manual testing' FROM DUAL UNION ALL
    select 2,'test', 'test' FROM DUAL UNION ALL
    SELECT 3,'manual testing','this is an old method of testing' FROM DUAL UNION ALL
    SELECT 4,'punctuation','automation testing,manual testing,punctuation,automanual testing-testing' FROM DUAL UNION ALL
    SELECT 5,'B-number analysis','B-number analysis table' FROM DUAL UNION ALL
    SELECT 6,'B-number analysis table','testing B-number analysis' FROM DUAL UNION ALL
    SELECT 7,'Not Matched','testing testing testing' FROM DUAL UNION ALL
    SELECT 8,'^[($','testing characters ^[($ that need escaping in a regular expression' FROM DUAL;
    

    SQL Types:

    CREATE TYPE stringlist IS TABLE OF VARCHAR2(4000);
    /
    CREATE TYPE intlist IS TABLE OF NUMBER(20,0);
    /
    

    PL/SQL Function:

    CREATE FUNCTION replace_words(
      word_list IN  stringlist,
      id_list   IN  intlist,
      sentence  IN  temp.sentence%TYPE
    ) RETURN temp.sentence%TYPE
    IS
      p_sentence       temp.sentence%TYPE := UPPER( sentence );
      p_pos            PLS_INTEGER := 1;
      p_min_word_index PLS_INTEGER;
      p_word_index     PLS_INTEGER;
      p_start          PLS_INTEGER;
      p_index          PLS_INTEGER;
      o_sentence       temp.sentence%TYPE;
    BEGIN
      LOOP
        p_min_word_index := NULL;
        p_index          := NULL;
        FOR i IN 1 .. word_list.COUNT LOOP
          p_word_index := p_pos;
          LOOP
            p_word_index := INSTR( p_sentence, word_list(i), p_word_index );
            EXIT WHEN p_word_index = 0;
            IF (   p_word_index  > 1
               AND REGEXP_LIKE( SUBSTR( p_sentence, p_word_index - 1, 1 ), '\w' )
               )
               OR  REGEXP_LIKE( SUBSTR( p_sentence, p_word_index + LENGTH( word_list(i) ), 1 ), '\w' )
            THEN
               p_word_index := p_word_index + 1;
               CONTINUE;
            END IF;
            IF p_min_word_index IS NULL OR p_word_index < p_min_word_index THEN
              p_min_word_index := p_word_index;
              p_index := i;
            END IF;
            EXIT;
          END LOOP;
        END LOOP;
        IF p_index IS NULL THEN
          o_sentence := o_sentence || SUBSTR( sentence, p_pos );
          EXIT;
        ELSE
          o_sentence := o_sentence
                        || SUBSTR( sentence, p_pos, p_min_word_index - p_pos )
                        || 'http://localhost/'
                        || id_list(p_index)
                        || '/<u>'
                        || SUBSTR( sentence, p_min_word_index, LENGTH( word_list( p_index ) ) )
                        || '</u>';
          p_pos := p_min_word_index + LENGTH( word_list( p_index ) );
        END IF;
      END LOOP;
      RETURN o_sentence;
    END;
    /
    

    Merge:

    MERGE INTO temp dst
    USING (
      WITH lists ( word_list, id_list ) AS (
        SELECT CAST(
                 COLLECT(
                   UPPER( word )
                   ORDER BY LENGTH( word ) DESC, UPPER( word ) ASC, ROWNUM
                 )
                 AS stringlist
               ),
               CAST(
                 COLLECT(
                   id
                   ORDER BY LENGTH( word ) DESC, UPPER( word ) ASC, ROWNUM
                 )
                 AS intlist
               )
        FROM   temp
      )
      SELECT t.ROWID rid,
             replace_words(
               word_list,
               id_list,
               sentence
             ) AS replaced_sentence
      FROM   temp t
             CROSS JOIN lists
    ) src
    ON ( dst.ROWID = src.RID )
    WHEN MATCHED THEN
      UPDATE SET sentence = src.replaced_sentence;
    

    Output:

    SELECT * FROM temp;
    
    ID | WORD                    | SENTENCE                                                                                                                                                                                                  
    -: | :---------------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
     1 | automation testing      | automtestingation http://localhost/2/<u>TeStInG</u> http://localhost/2/<u>TEST</u> is popular kind of http://localhost/2/<u>testing</u>                                                                   
     2 | testing                 | http://localhost/3/<u>manual testing</u>                                                                                                                                                                  
     2 | test                    | http://localhost/2/<u>test</u>                                                                                                                                                                            
     3 | manual testing          | this is an old method of http://localhost/2/<u>testing</u>                                                                                                                                                
     4 | punctuation             | http://localhost/1/<u>automation testing</u>,http://localhost/3/<u>manual testing</u>,http://localhost/4/<u>punctuation</u>,automanual http://localhost/2/<u>testing</u>-http://localhost/2/<u>testing</u>
     5 | B-number analysis       | http://localhost/6/<u>B-number analysis table</u>                                                                                                                                                         
     6 | B-number analysis table | http://localhost/2/<u>testing</u> http://localhost/5/<u>B-number analysis</u>                                                                                                                             
     7 | Not Matched             | http://localhost/2/<u>testing</u> http://localhost/2/<u>testing</u> http://localhost/2/<u>testing</u>                                                                                                     
     8 | ^[($                    | http://localhost/2/<u>testing</u> characters http://localhost/8/<u>^[($</u> that need escaping in a regular expression                                                                                    
    

    db<>fiddle here