Is it possible to auto-generate a GUID into an Insert statement?
Also, what type of field should I use to store this GUID?
You can use the SYS_GUID() function to generate a GUID in your insert statement:
insert into mytable (guid_col, data) values (sys_guid(), 'xxx');
The preferred datatype for storing GUIDs is RAW(16).
As Gopinath answer:
select sys_guid() from dual
union all
select sys_guid() from dual
union all
select sys_guid() from dual
You get
88FDC68C75DDF955E040449808B55601
88FDC68C75DEF955E040449808B55601
88FDC68C75DFF955E040449808B55601
As Tony Andrews says, differs only at one character
88FDC68C75DDF955E040449808B55601
88FDC68C75DEF955E040449808B55601
88FDC68C75DFF955E040449808B55601
Maybe useful: http://feuerthoughts.blogspot.com/2006/02/watch-out-for-sequential-oracle-guids.html
You can also include the guid in the create statement of the table as default, for example:
create table t_sysguid
( id raw(16) default sys_guid() primary key
, filler varchar2(1000)
)
/
See here: http://rwijk.blogspot.com/2009/12/sysguid.html
Example found on:
http://www.orafaq.com/usenet/comp.databases.oracle.server/2006/12/20/0646.htm
SELECT REGEXP_REPLACE(SYS_GUID(), '(.{8})(.{4})(.{4})(.{4})(.{12})', '\1-\2-\3-\4-\5') MSSQL_GUID FROM DUAL
Result:
6C7C9A50-3514-4E77-E053-B30210AC1082
It is not clear what you mean by auto-generate a guid into an insert statement but at a guess, I think you are trying to do something like the following:
INSERT INTO MY_TAB (ID, NAME) VALUES (SYS_GUID(), 'Adams');
INSERT INTO MY_TAB (ID, NAME) VALUES (SYS_GUID(), 'Baker');
In that case I believe the ID column should be declared as RAW(16);
I am doing this off the top of my head. I don't have an Oracle instance handy to test against, but I think that is what you want.
sys_guid() is a poor option, as other answers have mentioned. One way to generate UUIDs and avoid sequential values is to generate random hex strings yourself:
select regexp_replace(
to_char(
DBMS_RANDOM.value(0, power(2, 128)-1),
'FM0xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'),
'([a-f0-9]{8})([a-f0-9]{4})([a-f0-9]{4})([a-f0-9]{4})([a-f0-9]{12})',
'\1-\2-\3-\4-\5') from DUAL;
If you need non-sequential guids you can send the sys_guid() results through a hashing function (see https://stackoverflow.com/a/22534843/1462295 ). The idea is to keep whatever uniqueness is used from the original creation, and get something with more shuffled bits.
For instance:
LOWER(SUBSTR(STANDARD_HASH(SYS_GUID(), 'SHA1'), 0, 32))
Example showing default sequential guid vs sending it through a hash:
SELECT LOWER(SYS_GUID()) AS OGUID FROM DUAL
UNION ALL
SELECT LOWER(SYS_GUID()) AS OGUID FROM DUAL
UNION ALL
SELECT LOWER(SYS_GUID()) AS OGUID FROM DUAL
UNION ALL
SELECT LOWER(SYS_GUID()) AS OGUID FROM DUAL
UNION ALL
SELECT LOWER(SUBSTR(STANDARD_HASH(SYS_GUID(), 'SHA1'), 0, 32)) AS OGUID FROM DUAL
UNION ALL
SELECT LOWER(SUBSTR(STANDARD_HASH(SYS_GUID(), 'SHA1'), 0, 32)) AS OGUID FROM DUAL
UNION ALL
SELECT LOWER(SUBSTR(STANDARD_HASH(SYS_GUID(), 'SHA1'), 0, 32)) AS OGUID FROM DUAL
UNION ALL
SELECT LOWER(SUBSTR(STANDARD_HASH(SYS_GUID(), 'SHA1'), 0, 32)) AS OGUID FROM DUAL
output
80c32a4fbe405707e0531e18980a1bbb
80c32a4fbe415707e0531e18980a1bbb
80c32a4fbe425707e0531e18980a1bbb
80c32a4fbe435707e0531e18980a1bbb
c0f2ff2d3ef7b422c302bd87a4588490
d1886a8f3b4c547c28b0805d70b384f3
a0c565f3008622dde3148cfce9353ba7
1c375f3311faab15dc6a7503ce08182c
You can run the following query
select sys_guid() from dual
union all
select sys_guid() from dual
union all
select sys_guid() from dual
you can use function bellow in order to generate your UUID
create or replace FUNCTION RANDOM_GUID
RETURN VARCHAR2 IS
RNG NUMBER;
N BINARY_INTEGER;
CCS VARCHAR2 (128);
XSTR VARCHAR2 (4000) := NULL;
BEGIN
CCS := '0123456789' || 'ABCDEF';
RNG := 15;
FOR I IN 1 .. 32 LOOP
N := TRUNC (RNG * DBMS_RANDOM.VALUE) + 1;
XSTR := XSTR || SUBSTR (CCS, N, 1);
END LOOP;
RETURN SUBSTR(XSTR, 1, 4) || '-' ||
SUBSTR(XSTR, 5, 4) || '-' ||
SUBSTR(XSTR, 9, 4) || '-' ||
SUBSTR(XSTR, 13,4) || '-' ||
SUBSTR(XSTR, 17,4) || '-' ||
SUBSTR(XSTR, 21,4) || '-' ||
SUBSTR(XSTR, 24,4) || '-' ||
SUBSTR(XSTR, 28,4);
END RANDOM_GUID;
Example of GUID genedrated by the function above:
8EA4-196D-BC48-9793-8AE8-5500-03DC-9D04
I would recommend using Oracle's "dbms_crypto.randombytes" function.
Why?
This function returns a RAW value containing a cryptographically secure pseudo-random sequence of bytes, which can be used to generate random material for encryption keys.
select REGEXP_REPLACE(dbms_crypto.randombytes(16), '(.{8})(.{4})(.{4})(.{4})(.{12})', '\1-\2-\3-\4-\5') from dual;
You should not use the function "sys_guid" because only one character changes.
ALTER TABLE locations ADD (uid_col RAW(16));
UPDATE locations SET uid_col = SYS_GUID();
SELECT location_id, uid_col FROM locations
ORDER BY location_id, uid_col;
LOCATION_ID UID_COL
----------- ----------------------------------------------------------------
1000 09F686761827CF8AE040578CB20B7491
1100 09F686761828CF8AE040578CB20B7491
1200 09F686761829CF8AE040578CB20B7491
1300 09F68676182ACF8AE040578CB20B7491
1400 09F68676182BCF8AE040578CB20B7491
1500 09F68676182CCF8AE040578CB20B7491
https://docs.oracle.com/database/121/SQLRF/functions202.htm#SQLRF06120
Creating a 350 characters GUID:
dbms_random.STRING ('a', 350) - returning string in mixed case alpha characters
dbms_random.STRING ('x', 350) - returning string in uppercase alpha-numeric characters
Related
I created a dummy database for learning purposes, and I purposefully created some duplicated records in one of the tables. In every case I want to flag one of the duplicated records as Latest='Y', and the other record as 'N', and for every single record the Latest flag would be 'Y'.
I tried to use PlSQL to go through all of my records, but when I try to use the previously calculated value (which would tell that its a duplicated record) it says that:
ORA-06550: line 20, column 17:
PLS-00201: identifier 'COUNTER' must be declared
Here is the statement I try to use:
DECLARE
CURSOR cur
IS
SELECT order_id, order_date, person_id,
amount, successfull_order, country_id, latest, ROWCOUNT AS COUNTER
FROM (SELECT order_id,
order_date,
person_id,
amount,
successfull_order,
country_id,
latest,
ROW_NUMBER () OVER (PARTITION BY order_id, order_date,
person_id, amount, successfull_order, country_id
ORDER BY order_id, order_date,
person_id, amount, successfull_order, country_id) ROWCOUNT
FROM orders) orders
FOR UPDATE OF orders.latest;
rec cur%ROWTYPE;
BEGIN
FOR rec IN cur
LOOP
IF MOD (COUNTER, 2) = 0
THEN
UPDATE orders
SET latest = 'N'
WHERE CURRENT OF cur;
ELSE
UPDATE orders
SET latest = 'Y'
WHERE CURRENT OF cur;
END IF;
END LOOP;
END;
I am new to PlSQL so I tried to modify the statements I found here:
http://www.adp-gmbh.ch/ora/plsql/cursors/for_update.html
What should I change in my statement, or should I use a different approach?
Thanks for your answers in advance!
Botond
Your refer the ROWNUM as COUNTER in your cursor.
While fetching, you should be accessing it from the cursor reference like MOD (rec.COUNTER, 2)
You need to declare the variable COUNTER and then you need to maintain (ie increment) it in your loop.
I suspect that you example is just for learning PL/SQL. However be aware that it's often much more performant to do things with a single SQL statement, as opposed to using cursor loops.
Your issue is that COUNTER is an attribute of the cursor record rec and not a PL/SQL variable. So:
IF MOD (COUNTER, 2) = 0
Should be:
IF MOD (rec.COUNTER, 2) = 0
However, you do not need to use PL/SQL or cursors, it can be done in a single MERGE statement:
Oracle Setup:
CREATE TABLE orders ( order_id, order_date, latest ) AS
SELECT 1, DATE '2017-01-01', CAST( NULL AS CHAR(1) ) FROM DUAL UNION ALL
SELECT 1, DATE '2017-01-02', NULL FROM DUAL UNION ALL
SELECT 1, DATE '2017-01-03', NULL FROM DUAL UNION ALL
SELECT 2, DATE '2017-01-04', NULL FROM DUAL UNION ALL
SELECT 2, DATE '2017-01-01', NULL FROM DUAL UNION ALL
SELECT 3, DATE '2017-01-06', NULL FROM DUAL;
Update Statement:
MERGE INTO orders dst
USING ( SELECT ROW_NUMBER() OVER ( PARTITION BY order_id
ORDER BY order_date DESC ) AS rn
FROM orders
) src
ON ( src.ROWID = dst.ROWID )
WHEN MATCHED THEN
UPDATE SET latest = CASE src.rn WHEN 1 THEN 'Y' ELSE 'N' END;
Output:
SELECT * FROM orders;
ORDER_ID ORDER_DATE LATEST
-------- ---------- ------
1 2017-01-01 N
1 2017-01-02 N
1 2017-01-03 Y
2 2017-01-04 Y
2 2017-01-01 N
3 2017-01-06 Y
I work on this query and get this error:
Oracle - ORA-01489: result of string concatenation is too long
Some one please help to solve this issue
SELECT LISTAGG(RCRDNUM) WITHIN GROUP (ORDER BY RCRDNUM)
FROM (SELECT (ERR.RCRDNUM || ',') AS RCRDNUM
FROM TABLENAME ERR
INNER JOIN (SELECT UPPER(REGEXP_SUBSTR('No value present for CNTRY_CD column for the record',
'[^,]+', 1, LEVEL)) ERR_MSG
FROM DUAL
CONNECT BY REGEXP_SUBSTR('No value present for CNTRY_CD column for the record',
'[^,]+', 1, LEVEL)
IS NOT NULL) ERRMSG_P
ON (UPPER(ERR.ERRMSG) = ERRMSG_P.ERR_MSG
OR 'No value present for CNTRY_CD column for the record' IS NULL))
If the aggregate list is a string longer than 4000 characters, the string needs to be a CLOB, and you can't use listagg(). However, you can use xmlagg(), which does not have the 4000 character limit. The result must be a CLOB though - and it is cast as CLOB in the solution.
. Here is a proof-of-concept; I will let you adapt it to your situation.
with a (id,val) as (select 10, 'x' from dual union all select 20, 'abc' from dual)
select listagg(val, ',') within group (order by id) as l_agg,
rtrim( xmlcast( xmlagg( xmlelement(e, val || ',') order by id) as clob), ',')
as clob_agg
from a
;
Output
L_AGG CLOB_AGG
---------- ----------
x,abc x,abc
In Oracle's SQL queries, strings (columns of type VARCHAR) are limited to 4000 characters. Obviously, your query creates longer strings and therefore fails. This can easily happen with LISTAGG.
Should your query really return such long strings? If not, you need to work on your query.
If you really need values longer than 4000 characters, you can try to use CLOB instead of VARCHAR by using a custom user-defined aggregation function. Tom Kyte has an example in one of his questions.
I have a table say STAFF like below:
STAFF_NAME
============
ALEX
BERNARD
CARL
DOMINIC
EMMA
Now, I want to write a stored function with a single argument. E.g. GET_NEXT_STAFF(CURRENT_STAFF).
The input and output should be like:
Input | Output
=====================
NULL | ALEX
ALEX | BERNARD
BERNARD | CARL
EMMA | ALEX (Start from the beginning of the table again)
I know how to handle this problem using PL/SQL, but is it possible to deal with this problem with a single select statement?
In the solution below, I assume the rows are ordered alphabetically by names. They may be ordered by another column in the same table (for example by hire date, or by salary, etc. - it doesn't matter) - then the name of that column should be used in the ORDER BY clause of the two analytic functions.
The input name is passed in as a bind variable, :input_staff_name. The solution uses pure SQL, with no need for functions (PL/SQL), but if you must make it into a function, you can adapt it easily.
Edit: In my original answer I missed the required behavior when the input is null. The last line of code (excluding the semicolon) takes care of that. As written currently, the query returns ALEX (or in general the first value in the table) when the input is null, and it returns no rows when the input is not null and not in the table. If instead the requirement is to return the first name when the input is null or not found in the table, then it can be accommodated easily by removing and :input_staff_name is null from the last line.
with
tbl ( staff_name ) as (
select 'ALEX' from dual union all
select 'BERNARD' from dual union all
select 'CARL' from dual union all
select 'DOMINIC' from dual union all
select 'EMMA' from dual
),
prep ( staff_name, next_name, first_name ) as (
select staff_name,
lead(staff_name) over (order by staff_name),
first_value (staff_name) over (order by staff_name)
from tbl
)
select nvl(next_name, first_name) as next_staff_name
from prep
where staff_name = :input_staff_name
or (next_name is null and :input_staff_name is null)
;
Based on the answer from #mathguy I have made a few changes that seem to work. I have added the follow
UNION ALL
SELECT NULL
FROM DUAL
and
WHERE NVL (staff_name, 'X') = NVL (NULL, 'X');
The full code
WITH tbl (staff_name) AS
(SELECT 'ALEX' FROM DUAL
UNION ALL
SELECT 'BERNARD' FROM DUAL
UNION ALL
SELECT 'CARL' FROM DUAL
UNION ALL
SELECT 'DOMINIC' FROM DUAL
UNION ALL
SELECT 'EMMA' FROM DUAL
UNION ALL
SELECT NULL
FROM DUAL),
prep (staff_name,
next_name,
first_name,
last_name) AS
(SELECT staff_name,
LEAD (staff_name) OVER (ORDER BY staff_name),
FIRST_VALUE (staff_name) OVER (ORDER BY staff_name),
LAG (staff_name) OVER (ORDER BY staff_name)
FROM tbl)
SELECT NVL (next_name, first_name) AS next_staff_name
FROM prep
WHERE NVL (staff_name, 'X') = NVL (:input_staff_name, 'X');
I am trying to reverse a string without using REVERSE function. I came across one example which is something like:
select listagg(letter) within group(order by lvl)
from
(SELECT LEVEL lvl, SUBSTR ('hello', LEVEL*-1, 1) letter
FROM dual
CONNECT BY LEVEL <= length('hello'));
Apart from this approach,is there any other better approach to do this?
If you're trying to avoid the undocumented reverse() function you could use the utl_raw.reverse() function instead, with appropriate conversion too and from RAW:
select utl_i18n.raw_to_char(
utl_raw.reverse(
utl_i18n.string_to_raw('Some string', 'AL32UTF8')), 'AL32UTF8')
from dual;
UTL_I18N.RAW_TO_CHAR(UTL_RAW.REVERSE(UTL_I18N.STRING_TO_RAW('SOMESTRING','AL32UT
--------------------------------------------------------------------------------
gnirts emoS
So that is taking an original value; doing utl_i18n.string_to_raw() on that; then passing that to utl_raw.reverse(); then passing the result of that back through utl_i18n.raw_to_char().
Not entirely sure how that will cope with multibyte characters, or what you'd want to happen to those anyway...
Or a variation from the discussion #RahulTripathi linked to, without the character set handling:
select utl_raw.cast_to_varchar2(utl_raw.reverse(utl_raw.cast_to_raw('Some string')))
from dual;
UTL_RAW.CAST_TO_VARCHAR2(UTL_RAW.REVERSE(UTL_RAW.CAST_TO_RAW('SOMESTRING')))
--------------------------------------------------------------------------------
gnirts emoS
But that thread also notes it only works for single-byte characters.
You could do it like this:
with strings as (select 'hello' str from dual union all
select 'fred' str from dual union all
select 'this is a sentance.' from dual)
select str,
replace(sys_connect_by_path(substr (str, level*-1, 1), '~|'), '~|') rev_str
from strings
where connect_by_isleaf = 1
connect by prior str = str --added because of running against several strings at once
and prior sys_guid() is not null --added because of running against several strings at once
and level <= length(str);
STR REV_STR
------------------- --------------------
fred derf
hello olleh
this is a sentance. .ecnatnes a si siht
N.B. I used a delimiter of ~| simply because that's something unlikely to be part of your string. You need to supply a non-null delimiter to the sys_connect_by_path, hence why I didn't just leave it blank!
SELECT LISTAGG(STR) WITHIN GROUP (ORDER BY RN DESC)
FROM
(
SELECT ROWNUM RN, SUBSTR('ORACLE',ROWNUM,1) STR FROM DUAL
CONNECT BY LEVEL <= LENGTH('ORACLE')
);
You can try using this function:
SQL> ed
Wrote file afiedt.buf
1 with t as (select 'Reverse' as txt from dual)
2 select replace(sys_connect_by_path(ch,'|'),'|') as reversed_string
3 from (
4 select length(txt)-rownum as rn, substr(txt,rownum,1) ch
5 from t
6 connect by rownum <= length(txt)
7 )
8 where connect_by_isleaf = 1
9 connect by rn = prior rn + 1
10* start with rn = 0
SQL> /
Source
select listagg(rev)within group(order by rownum)
from
(select substr('Oracle',level*-1,1)rev from dual
connect by level<=length('Oracle'));
SELECT TO_NUMBER('*') FROM DUAL
This obviously gives me an exception:
ORA-01722: invalid number
Is there a way to "skip" it and get 0 or NULL instead?
The whole issue: I have NVARCHAR2 field, which contains numbers and not almost ;-) (like *) and I need to select the biggest number from the column.
Yes, I know it is a terrible design, but this is what I need now... :-S
UPD:
For myself I've solved this issue with
COALESCE(TO_NUMBER(REGEXP_SUBSTR(field, '^\d+')), 0)
From Oracle Database 12c Release 2 you could use TO_NUMBER with DEFAULT ... ON CONVERSION ERROR:
SELECT TO_NUMBER('*' DEFAULT 0 ON CONVERSION ERROR) AS "Value"
FROM DUAL;
Or CAST:
SELECT CAST('*' AS NUMBER DEFAULT 0 ON CONVERSION ERROR) AS "Value"
FROM DUAL;
db<>fiddle demo
COALESCE(TO_NUMBER(REGEXP_SUBSTR(field, '^\d+(\.\d+)?')), 0)
will also get numbers with scale > 0 (digits to the right of the decimal point).
I couldn't find anything better than this:
function safe_to_number(p varchar2) return number is
v number;
begin
v := to_number(p);
return v;
exception when others then return 0;
end;
select COALESCE(TO_NUMBER(REGEXP_SUBSTR( field, '^(-|+)?\d+(\.|,)?(\d+)?$')), 0) from dual;
It will convert 123 to 123, but 123a or 12a3 to 0.
Fitting the original question and rather old skool
select a, decode(trim(translate(b,'0123456789.',' ')),null,to_number(b),0) from
(
select '1' a, 'not a number' b from dual
union
select '2' a, '1234' b from dual
)
It's probably a bit messy rolling your own regexp to test for a number, but the code below might work. I think the other solution by Gabe involving a user defined function is more robust since you are using the built in Oracle functionality (and my regexp is probably not 100% correct) but it might be worth a go:
with my_sample_data as (
select '12345' as mynum from dual union all
select '54-3' as mynum from dual union all
select '123.4567' as mynum from dual union all
select '.34567' as mynum from dual union all
select '-0.3462' as mynum from dual union all
select '0.34.62' as mynum from dual union all
select '1243.64' as mynum from dual
)
select
mynum,
case when regexp_like(mynum, '^-?\d+(\.\d+)?$')
then to_number(mynum) end as is_num
from my_sample_data
This will then give the following output:
MYNUM IS_NUM
-------- ----------
12345 12345
54-3
123.4567 123.4567
.34567
-0.3462 -0.3462
0.34.62
1243.64 1243.64
select DECODE(trim(TRANSLATE(replace(replace(A, ' '), ',', '.'), '0123456789.-', ' ')),
null,
DECODE(INSTR(replace(replace(A, ' '), ',', '.'), '.', INSTR(replace(replace(A, ' '), ',', '.'), '.') + 1),
0,
DECODE(INSTR(replace(replace(A, ' '), ',', '.'), '-', 2),
0,
TO_NUMBER(replace(replace(A, ' '), ',', '.'))))) A
from (select '-1.1' A from DUAL union all select '-1-1' A from DUAL union all select ',1' A from DUAL union all select '1..1' A from DUAL) A;
This code excludes such strings as: -1-1, 1..1, 12-2 and so on. And I haven't used regular expressions here.
A combination of previous solutions (from #sOliver and #Mike Meyers) and trying to grab as much numbers as possible by removing the last '$' from REGEXP.
It can be used to filter the actual number from a configuration table, and have a "kind-of" comment next to the number as '12 Days'.
with my_sample_data as (
select '12345' as mynum from dual union all
select '123.4567' as mynum from dual union all
select '-0.3462' as mynum from dual union all
select '.34567' as mynum from dual union all
select '-.1234' as mynum from dual union all
select '**' as mynum from dual union all
select '0.34.62' as mynum from dual union all
select '24Days' as mynum from dual union all
select '42ab' as mynum from dual union all
select '54-3' as mynum from dual
)
SELECT mynum,
COALESCE( TO_NUMBER( REGEXP_SUBSTR( mynum, '^(-|+)?\d*(.|,)?(\d+)?') ) , 0) is_num
FROM my_sample_data;
would give
MYNUM IS_NUM
-------- ----------
12345 12345
123.4567 123.4567
-0.3462 -0.3462
.34567 0.34567
-.1234 -0.1234
** 0
0.34.62 0.34
24Days 24
42ab 42
54-3 54
Best method seems to be the function solution but if you don't have necessary privileges in the environment you are struggling (like me), then you can try this one:
SELECT
CASE
WHEN
INSTR(TRANSLATE('123O0',
' qwertyuıopğüasdfghjklşizxcvbnmöçQWERTYUIOPĞÜASDFGHJKLŞİZXCVBNMÖÇ~*\/(){}&%^#$<>;#€|:_=',
'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
),
'X') > 0
THEN 'Y'
ELSE 'N'
END is_nonnumeric
FROM DUAL
By the way: In my case the problem was due to "," and "." :) So take that into consider. Inspired from this one. Also this one seems more concise.
By the way 2: Dear Oracle, can you please create some built-in functions for such small but invaluable needs?