Вы можете создать функцию для обработки CLOB
значений любой длины:
скрипт SQL
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;
/
Настройка схемы Oracle 11g R2:
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;
/
Запрос 1:
SELECT DBMS_LOB.GETLENGTH( value )
FROM table_name
Результаты:
| DBMS_LOB.GETLENGTH(VALUE) |
|---------------------------|
| (null) |
| 0 |
| 10 |
| 5 |
| 405 |
| 405 |
| 405 |
| 4005 |
| 4005 |
| 4005 |
| 40005 |
| 40005 |
| 40005 |
Запрос 2:
UPDATE table_name
SET value = LOB_REPLACE(
value,
( SELECT str FROM replacements ),
( SELECT repl FROM replacements )
)
Запрос 3:
SELECT DBMS_LOB.GETLENGTH( value )
FROM table_name
Результаты:
| DBMS_LOB.GETLENGTH(VALUE) |
|---------------------------|
| (null) |
| 0 |
| 10 |
| 40000 |
| 40400 |
| 40400 |
| 40400 |
| 44000 |
| 44000 |
| 44000 |
| 80000 |
| 80000 |
| 80000 |
person
MT0
schedule
31.10.2017