Extracting separate information from a character string

I have been recently asked to develop a pl/sql stored procedure in order to dequeue a payload message from an Oracle Advanced queue. It was a text message. Don’t ask me why they didn’t foresee an object type for that purpose, I did asked the same question and I have been told that this is the standard they have been successfully using since several years and they do not have the intention to change it.

The goal is to dequeue that text message and extract from it several fields that are separated by a given delimiter.  I decided to reproduce this development in a blog article so that I can found it easily and also redirect to it when similar request will be done in Oracle forums.

mhouri.world> create or replace package split_text
3  IS
4   TYPE t_msg_array IS TABLE OF VARCHAR2(4000) INDEX BY BINARY_INTEGER;
7    FUNCTION f_extract_message_info (piv_message IN VARCHAR2
8                                    ,piv_delim   IN VARCHAR2)
9       RETURN t_msg_array;
11  END split_text;
12  /

Package created.

 

mhouri.world> create or replace package body split_text
2  IS
3  FUNCTION f_extract_message_info (piv_message IN VARCHAR2
5                                   ,piv_delim   IN VARCHAR2)
6     RETURN t_msg_array
7  IS
8     l_t_msg_array   t_msg_array;
9     ln_pos          NUMBER          := 0;
10     li              INTEGER         := 0;
11     lv_str          VARCHAR2 (4000) := piv_message;
12
13  BEGIN
14     -- Get the position fo the first delimitor
15     ln_pos := instr(lv_str,piv_delim,1,1);
16
17     -- While there is still delimitors loop
18     WHILE ( ln_pos != 0)
19     LOOP
20
21       -- Remove the first delimitor from the message
22       lv_str := substr(lv_str,ln_pos + length(piv_delim),length(lv_str));
23
24       -- Determine now the new position of the first delimiter
25       ln_pos := instr(lv_str,piv_delim,1,1);
26
27       -- Fill each information of the message in an array
28       li := li + 1;
29       IF ln_pos != 0
30       THEN
31         l_t_msg_array(li) := substr(lv_str,1, ln_pos-1);
32       ELSE
33         l_t_msg_array(li) := lv_str;
34       END IF;
35
36     END LOOP;
37
38     -- return the array
39      RETURN l_t_msg_array;
41  END f_extract_message_info;
44  END split_text;
45  /

Package body created.

Few points should be taken into account

1. piv_delim represents the fields delimiter
2. the message text should starts by the delimiter

And here below is a simple test of  this function:

mhouri.world> set serveroutput on

mhouri.world> declare
2   piv_txt            varchar2(4000);
3   l_t_jus_msg_array  split_text.t_msg_array;
4
5  BEGIN
6
7   piv_txt := '#@test01#@test02#@test03';
8
9   l_t_jus_msg_array     := split_text.f_extract_message_info(piv_txt,'#@');
10
11   dbms_output.put_line(' item1 := '||l_t_jus_msg_array(1) );
12   dbms_output.put_line(' item2 := '||l_t_jus_msg_array(2));
13   dbms_output.put_line(' item3 := '||l_t_jus_msg_array(3));
14
15
16  END;
17  /

item1 := test01
item2 := test02
item3 := test03

PL/SQL procedure successfully completed.

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