使用PL/SQL處理將包含CLOB的CLOB轉儲到csv

Question

我組裝了一個過程將包含CLOB列的查詢轉儲到csv文件。 它似乎工作正常，直到我遇到包含日期的查詢。

ORA-00932：不一致的數據類型：預期CLOB得到DATE

有沒有一種方法可以動態轉換的日期一些默認的字符串格式能夠使用的程序，因爲它是現在。或者我可以在必要時重構它？

create or replace 
PROCEDURE export_query_csv(
     p_query  IN VARCHAR2, 
     p_filename IN VARCHAR2) 
IS  
    l_separator VARCHAR2 (10 CHAR) := ';'; 
    l_dir   VARCHAR2 (128 CHAR) := 'MY_DIR'; 
    l_output  utl_file.file_type; 
    l_theCursor INTEGER DEFAULT dbms_sql.open_cursor; 
    l_columnValue CLOB; 
    l_status  INTEGER; 
    l_colCnt  NUMBER DEFAULT 0; 
    l_cnt   NUMBER DEFAULT 0; 
    l_descTbl  dbms_sql.desc_tab; 

    l_substrVal VARCHAR2(4000) ; 
    l_offset NUMBER :=1; 
    l_amount NUMBER := 3000; 
    l_clobLen NUMBER :=0; 
    BEGIN 
    EXECUTE IMMEDIATE 'alter session set nls_date_format = ''dd-mon-yyyy hh24:mi:ss'''; 

    l_output := utl_file.fopen(l_dir, p_filename, 'wb'); 

    dbms_sql.parse(l_theCursor, p_query, dbms_sql.native); 

    FOR i IN 1 .. 1000 
    LOOP 
     BEGIN 
     dbms_sql.define_column(l_theCursor, i, l_columnValue); 
     l_colCnt := i; 
     EXCEPTION 
     WHEN OTHERS THEN 
     IF (SQLCODE = -1007) THEN 
      EXIT; 
     ELSE 
      RAISE; 
     END IF; 
     END; 
    END LOOP; 

    dbms_sql.describe_columns(l_theCursor, l_colCnt, l_descTbl); 

    FOR i IN 1 .. l_colCnt 
    LOOP 
     utl_file.put_raw(l_output,utl_raw.cast_to_raw('"')); 
     utl_file.put_raw(l_output,utl_raw.cast_to_raw(l_descTbl(i).col_name)); 
     utl_file.put_raw(l_output,utl_raw.cast_to_raw('"')); 
     IF i < l_colCnt THEN 
     utl_file.put_raw(l_output,utl_raw.cast_to_raw(l_separator)); 
     END IF; 
    END LOOP; 

    utl_file.put_raw(l_output,utl_raw.cast_to_raw(chr(13) || chr(10))); 

    l_status := dbms_sql.execute(l_theCursor); 
    LOOP 
     EXIT WHEN (dbms_sql.fetch_rows(l_theCursor) <= 0); 
     FOR i IN 1 .. l_colCnt 
     LOOP 
     dbms_sql.column_value(l_theCursor, i, l_columnValue); 

     l_clobLen := dbms_lob.getlength(l_columnValue); 
     WHILE l_offset <= l_clobLen 
     LOOP 
      l_substrVal := dbms_lob.substr(l_columnValue,l_amount,l_offset); 
      utl_file.put_raw(l_output,utl_raw.cast_to_raw('"')); 
      utl_file.put_raw(l_output,utl_raw.cast_to_raw(l_substrVal)); 
      utl_file.put_raw(l_output,utl_raw.cast_to_raw('"')); 
      l_offset:=l_offset+l_amount; 
     END LOOP; 
     l_offset := 1; 

     IF i < l_colCnt THEN 
      utl_file.put_raw(l_output,utl_raw.cast_to_raw(l_separator)); 
     END IF; 
     END LOOP; 
     utl_file.put_raw(l_output,utl_raw.cast_to_raw(chr(13) || chr(10))); 
     l_cnt := l_cnt + 1; 
    END LOOP; 

    dbms_sql.close_cursor(l_theCursor); 
    utl_file.fclose(l_output); 

END; 

Answer 1

找到它自己，下面這個模式：

-- Define columns 
FOR i IN 1 .. colcnt LOOP 
    IF desctab(i).col_type = 2 THEN 
     DBMS_SQL.DEFINE_COLUMN(curid, i, numvar); 
    ELSIF desctab(i).col_type = 12 THEN 
     DBMS_SQL.DEFINE_COLUMN(curid, i, datevar); 
...... 
    ELSE 
     DBMS_SQL.DEFINE_COLUMN(curid, i, namevar); 
    END IF; 
END LOOP;