Hi actually m trying to insert the bulk records into the DB.
Records are more than the 20000.
I have to insert the records into three tables since these records are corelated.
For example :
1. One sort of data into the Table 1.
1.1 another sort of data into the Table 2.
1.1.1 another sort of data into the Table 3.
we can consider the above statement as nested lenter code hereoop.
Currently m using the Cursor for above approach but it is taking v v v v long time.
waiting for ur valuable suggestion....
It sounds like you want an INSERT ALL statement. Something like
INSERT ALL
WHEN (<<some condition>>) THEN
INTO table1( <<list of columns>> )
VALUES( <<list of columns>> )
WHEN (<<another condition>>) THEN
INTO table2( <<list of columns>> )
VALUES( <<list of columns>> )
WHEN (<<third condition>>) THEN
INTO table3( <<list of columns>> )
VALUES( <<list of columns>> )
SELECT <<list of columns>>
FROM <<source tables>>
WHERE <<some predicates>>
The SELECT statement at the end would generally be whatever query you're using to populate the cursor. The conditions would implement whatever logic you implement inside the loop to determine which table to insert the data into.
If you know that a row from the cursor will always be inserted into a single table, you could use an INSERT FIRST rather than an INSERT ALL (the rest of the syntax remains the same) so that Oracle can stop evaluating conditions once the first condition evaluates to TRUE.
Related
I'm playing around with array support in Oracle and hit a roadblock regarding array access within a SQL query. I'm using the following schema:
create type smallintarray as varray(10) of number(3,0);
create table tbl (
id number(19,0) not null,
the_array smallintarray,
primary key (id)
);
What I would like to do is get the id and the first element i.e. at index 1 of the array. In PostgreSQL I could write select id, the_array[1] from tbl t but I don't see how I could do that with Oracle. I read that array access by index is only possible in PL/SQL, which would be fine if I could return a "decorated cursor" to achieve the same result through JDBC, but I don't know if that's possible.
DECLARE
c1 SYS_REFCURSOR;
varr smallintarray2;
BEGIN
OPEN c1 FOR SELECT t.id, t.THE_ARRAY from tbl t;
-- SELECT t.THE_ARRAY INTO varr FROM table_with_enum_arrays2 t;
-- return a "decorated cursor" with varr(1) at select item position 1
dbms_sql.return_result(c1);
END;
You can do this in plain SQL; it's not pretty, but it does work. You would prefer that Oracle had syntax to hide this from the programmer (and perhaps it does, at least in the most recent versions; I am still stuck at 12.2).
select t.id, q.array_element
from tbl t cross apply
( select column_value as array_element,
rownum as ord
from table(the_array)
) q
where ord = 1
;
EDIT If order of generating the elements through the table operator is a concern, you could do something like this (in Oracle 12.1 and higher; otherwise the function can't be part of the query itself, but it can be defined on its own):
with
function select_element(arr smallintarray, i integer)
return number
as
begin
return arr(i);
end;
select id, select_element(the_array, 1) as the_array_1
from tbl
/
First of all, please don't do that on production. Use tables instead of storing arrays within a table.
Answer to your question is to use column as a table source
SELECT t.id, ta.*
from tbl t,
table(t.THE_ARRAY) ta
order by column_value
-- offset 1 row -- in case if sometime you'll need to skip a row
fetch first 1 row only;
UPD: as for ordering the array I can only say playing with 2asc/desc" parameters provided me with results I've expected - it has been ordered ascending or descending.
UPD2: found a cool link to description of performance issues might happen
Could you please tell me how to compare differences between table and my select query and insert those results in separate table? My plan is to create one base table (name RESULT) by using select statement and populate it with current result set. Then next day I would like to create procedure which will going to compare same select with RESULT table, and insert differences into another table called DIFFERENCES.
Any ideas?
Thanks!
You can create the RESULT_TABLE using CTAS as follows:
CREATE TABLE RESULT_TABLE
AS SELECT ... -- YOUR QUERY
Then you can use the following procedure which calculates the difference between your query and data from RESULT_TABLE:
CREATE OR REPLACE PROCEDURE FIND_DIFF
AS
BEGIN
INSERT INTO DIFFERENCES
--data present in the query but not in RESULT_TABLE
(SELECT ... -- YOUR QUERY
MINUS
SELECT * FROM RESULT_TABLE)
UNION
--data present in the RESULT_TABLE but not in the query
(SELECT * FROM RESULT_TABLE
MINUS
SELECT ... );-- YOUR QUERY
END;
/
I have used the UNION and the difference between both of them in a different order using MINUS to insert the deleted data also in the DIFFERENCES table. If this is not the requirement then remove the query after/before the UNION according to your requirement.
-- Create a table with results from the query, and ID as primary key
create table result_t as
select id, col_1, col_2, col_3
from <some-query>;
-- Create a table with new rows, deleted rows or updated rows
create table differences_t as
select id
-- Old values
,b.col_1 as old_col_1
,b.col_2 as old_col_2
,b.col_3 as old_col_3
-- New values
,a.col_1 as new_col_1
,a.col_2 as new_col_2
,a.col_3 as new_col_3
-- Execute the query once again
from <some-query> a
-- Outer join to detect also detect new/deleted rows
full join result_t b using(id)
-- Null aware comparison
where decode(a.col_1, b.col_1, 1, 0) = 0
or decode(a.col_2, b.col_2, 1, 0) = 0
or decode(a.col_3, b.col_3, 1, 0) = 0;
I have an insert statement that takes all its values from local variables or literal constants:
INSERT INTO SampleTestLimits
(AuditNumber
,LimitNumber
,ComponentRow
,ComponentColumn
--etc
)
SELECT 1
,varLimitNumber
,varComponentRow
,varComponentColumn
--etc
;
but the problem is that I get an error "Missing FROM".
I guessed that this is because there is no table associated with the Select, and I tried ending the query with
FROM DUAL;
but that doesn't work (possibly because DUAL is a single row, single column pseudo-table, or so I understand).
I can do this quite easily in Sql Server, but how can I do what I want to achieve in Oracle?
TIA.
If you want to insert data from local variables you should use the VALUES clause:
INSERT INTO SampleTestLimits
(AuditNumber
,LimitNumber
,ComponentRow
,ComponentColumn
--etc
)
VALUES
(1
,varLimitNumber
,varComponentRow
,varComponentColumn
--etc
);
Let say I have table my table has values(which they are varchar):
values
a
o
g
t
And I have insert a new value called V
values
V
a
o
g
t
Is there a way or query that can specify what is the last value was insert in the column ? the desired query : select * from dual where rown_num = count(*) -- just an example and the result will be V
Rows in a table have no inherent order. rownum is a pseudocolumn that's part of the select so it isn't useful here. There is no way to tell where in the storage a new row will physically be placed, so you can't rely on rowid, for example.
The only way to do this reliably is to have a timestamp column (maybe set by a trigger so you don't have to worry about it). That would let you order the rows by timestamp and find the row with the highest (most recent) timestamp.
You are still restricted by the precision of the timestamp, as I discovered creating a SQL Fiddle demo; without forcing a small gap between the inserts the timestamps were all the same, but then it only seems to support `timestamp(3). That probably won't be a significant issue in the real world, unless you're doing bulk inserts, but then the last row inserted is still a bit of an arbitrary concept.
As quite correctly pointed out in comments, if the actual time doesn't need to be know, a numeric field populated by a sequence would be more reliable and performant; another SQL Fiddle demo here, and this is the gist:
create table t42(data varchar2(10), id number);
create sequence seq_t42;
create trigger bi_t42
before insert on t42
for each row
begin
:new.id := seq_t42.nextval;
end;
/
insert into t42(data) values ('a');
insert into t42(data) values ('o');
insert into t42(data) values ('g');
insert into t42(data) values ('t');
insert into t42(data) values ('V');
select data from (
select data, row_number() over (order by id desc) as rn
from t42
)
where rn = 1;
In PL SQL, I'm writing a stored procedure that uses a DB link:
CREATE OR REPLACE PROCEDURE Order_Migration(us_id IN NUMBER, date_id in DATE)
as
begin
INSERT INTO ORDERS(order_id, company_id)
SELECT ORDER_ID_SEQ.nextval, COMPANY_ID
FROM ORDERS#SOURCE
WHERE USER_ID = us_id AND DUE_DATE = date_ID;
end;
It takes all orders done on a certain day, by a certain user and inserts them in the new database. It calls a sequence to makes sure there are no repeat PKs on the orders, and it works well.
However, I want the same procedure to do a second INSERT into another table that has order_id as a foreign key. So I need to add all the order_id's just created, and the data from SOURCE that matches:
INSERT INTO ORDER_COMPLETION(order_id, completion_dt)
SELECT ????, completion_dt
FROM ORDER_COMPLETION#SOURCE
How can I keep track of which order_id that was just created matches up to the one whose data I need to pull from the source database?
I looked into making a temporary table, but you can't create those in a procedure.
Other info: I'll be calling this procedure from a C# app I'm writing
I'm not sure that I follow the question. If there is an ORDERS table and an ORDER_COMPLETION table in the remote database, wouldn't there be some key on the source system that related those two tables? If that key is the ORDER_ID, why would you want to re-assign that key in your procedure? Wouldn't you want to maintain the ORDER_ID from the source system?
If you do want to re-assign the ORDER_ID locally, I would tend to think that you'd want to do something like
CREATE OR REPLACE PROCEDURE order_migration( p_user_id IN orders.user_id%type,
p_due_date IN orders.due_date%type )
AS
TYPE order_rec IS RECORD( new_order_id NUMBER,
old_order_id NUMBER,
company_id NUMBER,
completion_dt DATE );
TYPE order_arr IS TABLE OF order_rec;
l_orders order_arr;
BEGIN
SELECT order_id_seq.nextval,
o.order_id,
o.company_id,
oc.completion_dt
BULK COLLECT INTO l_orders
FROM orders#source o,
order_completion#source oc
WHERE o.order_id = oc.order_id
AND o.user_id = p_user_id
AND o.due_date = p_due_date;
FORALL i IN l_orders.FIRST .. l_orders.LAST
INSERT INTO orders( order_id, company_id )
VALUES( l_orders(i).new_order_id, l_orders(i).company_id );
FORALL i IN l_orders.FIRST .. l_orders.LAST
INSERT INTO order_completion( order_id, completion_dt )
VALUES( l_orders(i).new_order_id, l_orders(i).completion_dt );
END;
You could also do a single FOR loop with two INSERT statements rather than two FORALL loops. And if you're pulling a lot of data each time, you probably want to pull the data in chunks from the remote system by adding a loop and a LIMIT to the BULK COLLECT
There must be some link between the rows in ORDERS#SOURCE and ORDERS, and between ORDERS#SOURCE and ORDER_COMPLETION#SOURCE, so can you not use a join?
Something like:
INSERT INTO ORDER_COMPLETION(order_id, completion_dt)
SELECT o.order_id, ocs.completion_dt
FROM ORDER_COMPLETION#SOURCE ocs
JOIN ORDERS o ON o.xxx = ocs.xxx