2016年10月26日星期三

Oracle - blob_to_clob

create or replace FUNCTION blob_to_clob (blob_in IN BLOB)
RETURN CLOB
AS
v_clob CLOB;
v_varchar VARCHAR2(32767);
v_start PLS_INTEGER := 1;
v_buffer PLS_INTEGER := 32767;
BEGIN
DBMS_LOB.CREATETEMPORARY(v_clob, TRUE);
FOR i IN 1..CEIL(DBMS_LOB.GETLENGTH(blob_in) / v_buffer)
LOOP
   v_varchar := UTL_RAW.CAST_TO_VARCHAR2(DBMS_LOB.SUBSTR(blob_in, v_buffer, v_start));
DBMS_LOB.WRITEAPPEND(v_clob, LENGTH(v_varchar), v_varchar);
v_start := v_start + v_buffer;
END LOOP;
RETURN v_clob;
END blob_to_clob;

Oracle - c2b

create or replace FUNCTION                c2b( c IN CLOB ) RETURN BLOB
IS
position PLS_INTEGER := 1;
buffer RAW( 32767 );
res BLOB;
lob_len PLS_INTEGER := DBMS_LOB.getLength( c );
BEGIN
DBMS_LOB.createTemporary( res, TRUE );
DBMS_LOB.OPEN( res, DBMS_LOB.LOB_ReadWrite );
LOOP
buffer := UTL_RAW.cast_to_raw( DBMS_LOB.SUBSTR( c, 10000, position ) );
IF UTL_RAW.LENGTH( buffer ) > 0 THEN
DBMS_LOB.writeAppend( res, UTL_RAW.LENGTH( buffer ), buffer );
END IF;
position := position + 10000;
EXIT WHEN position > lob_len;
END LOOP;
RETURN res;
END c2b;