提取 CLOB 数据以进行插入

Question

我有这样的 CLOB 数据：

123456 (LED TV); 234543 (LED light); 654876 (LED monitor);

现在我需要使用定界符（在我的例子中是“;”）和 select 用于插入目标 table 但仅当记录不存在时。

我看过几个 Instr & Substr 或 Regexp 的例子，但没有我需要的或超出我对 Oracle 的理解。有人能给我一个例子，说明如何根据 CLOB 中的字符串将 CLOB 拆分成行，以便稍后插入时使用它吗？

P.S.: 我更喜欢最快的解决方案，因为我的 CLOB 数据可能包含超过 500 万条发票记录。最后将是一个从 C# 触发的存储过程，但这部分让我很头疼...如有任何帮助 - 在此先感谢！

Answer 1

举个例子。

先测试用例； test table 包含源数据：

SQL> create table test (col clob);

Table created.

SQL> insert into test
  2    select '123456 (LED TV); 234543 (LED light); 654876 (LED monitor);' from dual union all
  3    select '665988 (Notebook); 987654 (Mouse); 445577 (Dead Pixel);'    from dual;

2 rows created.

SQL>

Target table 将包含从源中提取的值：

SQL> create table target (itn number, name varchar2(20));

Table created.

SQL> -- This value shouldn't be inserted as it already exists in the TARGET table:
SQL> insert into target values (234543, 'LED light');

1 row created.

SQL>

现在，一些有用的东西。这个想法是将列值拆分为行（这就是分层查询中的 regexp_substr 部分所做的，然后将 ID 值与名称（括在括号中）分开。目标 [=27= 中存在的值] 不应插入（因此查询应该插入 5 行）：

SQL> insert into target (itn, name)
  2  with
  3  c2r as
  4    -- split column to rows, e.g. "123456 (LED TV)" is an example of such a row
  5    (select to_char(trim(regexp_substr(col, '[^;]+', 1, column_value))) val
  6     from test join table(cast(multiset(select level from dual
  7                                        connect by level <= regexp_count(col, ';')
  8                                       ) as sys.odcinumberlist)) on 1 = 1
  9    ),
 10  sep as
 11    -- separate ITN (invoice tracking nubmer) and NAME
 12    (select substr(val, 1, instr(val, ' ') - 1) itn,
 13            substr(val, instr(val, ' ') + 1) name
 14     from c2r
 15    )
 16  select s.itn, replace(replace(s.name, '(', ''), ')', '')
 17  from sep s
 18  -- don't insert values that already exist in the TARGET table
 19  where not exists (select null from target t
 20                    where t.itn = s.itn
 21                   );

5 rows created.

SQL>

最终结果：

SQL> select * From target;

       ITN NAME
---------- --------------------
    234543 LED light
    123456 LED TV
    654876 LED monitor
    665988 Notebook
    987654 Mouse
    445577 Dead Pixel

6 rows selected.

SQL>

Answer 2

我尝试使用 DBMS_LOB 包将它们转换为除以 ";" 的字符串来完成任务，然后对其进行一些字符串操作以实现结果。

尝试以下操作：

INSERT INTO INVOICE_CATEGORIZED 
SELECT TAB.INVOICE_NUMBER, TAB.INVOICE_NAME FROM
(SELECT 
TRIM(dbms_lob.SUBSTR(INVOICE_INN,6 ,1)) AS INVOICE_NUMBER, 

SUBSTR(INVOICE_INN, 
INSTR(INVOICE_INN, '(') + 1,
INSTR(INVOICE_INN, ')') - INSTR(INVOICE_INN, '(') - 1 )
 AS INVOICE_NAME

-- HERE INVOICE_INN IS STRING NOW, SO WE CAN DO STRING OPERATIONS ON IT ONWARD

FROM
(
-- DIVIDING ; SEPARATED CLOB TO INDIVIDUAL STRING
SELECT
    TRIM(CASE WHEN INVOICE_SINGLE.COLUMN_VALUE = 1 THEN
    dbms_lob.SUBSTR(INVOICE, 
    dbms_lob.INSTR(INVOICE,';',1,INVOICE_SINGLE.COLUMN_VALUE) - 1,
    1 
    )
    ELSE
    dbms_lob.SUBSTR(INVOICE, 
    dbms_lob.INSTR(INVOICE,';',1,INVOICE_SINGLE.COLUMN_VALUE) - 1
    - dbms_lob.INSTR(INVOICE,';',1,INVOICE_SINGLE.COLUMN_VALUE - 1),
    dbms_lob.INSTR(INVOICE,';',1,INVOICE_SINGLE.COLUMN_VALUE - 1) + 1)
    END) AS INVOICE_INN
FROM
    INVOICES T,
    TABLE ( CAST(MULTISET(
        SELECT
            LEVEL
        FROM
            DUAL
        CONNECT BY
            dbms_lob.INSTR(INVOICE,';',1,LEVEL) <> 0
    ) AS SYS.ODCINUMBERLIST) ) INVOICE_SINGLE)) TAB 
     WHERE NOT EXISTS (SELECT 1 FROM INVOICE_CATEGORIZED IC
    WHERE IC.INVOICE_NUMBER  = TAB.INVOICE_NUMBER
    AND IC.INVOICE_NAME = TAB.INVOICE_NAME)

db<>fiddle demo

干杯！！

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