What is the data type of ORA_ROWSCN? It seems to be NUMBER but I cannot find it specified in the documentation.
declare
myscn ???;
begin
select ora_rowscn into myscn from t where ...;
end;
It is a NUMBER. You can see yourself by creating a simple view and describing it (or selecting from *_tab_columns). Here's a simple sqlfiddle demonstration
create table foo (
col1 number
);
create view vw_foo
as
select col1, ora_rowscn scn
from foo;
select *
from user_tab_cols
where table_name = 'VW_FOO';
If you want more detail than you'd probably ever care about on the format of the SCN (system change number), here is one decent article
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
I have a procedure where it has few select statements (from different tables) and the output of these select statements will be loaded into a temp table. All the records which are loaded in this temp table will be displayed as an output. Now I have a requirement where my procedure should not have this temp table.
Can you please let me know the options of achieving it?
Assuming that the SELECT queries have same number of COLUMNS and Datatype. Your best approach could be using union all and refcursor to display the output. Hope below snippet helps.
--You can try using nested table types here instead of using temp tables or simply UNIONALL
--Hope below example helps.
DECLARE
p_lst sys_refcursor;
BEGIN
--Assuming that all the SELECT statements have same number of columns as well as datatype
OPEN p_lst FOR
(SELECT 'AV',1 FROM DUAL
UNION ALL
SELECT'SH',2 FROM DUAL
UNION ALL
SELECT 'TK',3 FROM DUAL
);
END;
Assuming mysql...
You could do something like
UPDATE [table1] AS t1
INNER JOIN [table2] AS t2
ON t1.[col1] = t2.[col1]
SET t1.[col2] = t2.[col2];
I am new to PL-SQL. I do not understand why I am getting the error "PLS-00428: an INTO clause is expected in this SELECT statement"
What I'm trying to accomplish is to create a variable c_limit and load it's value. I then want to use that variable later to filter data.
Basically I am playing around in the demo db to see what I can/can't do with PL-SQL.
The code worked up to the point that I added "select * from demo_orders where CUSTOMER_ID = custID;"
declare
c_limit NUMBER(9,2);
custID INT;
BEGIN
custID := 6;
-- Save the credit limit
select credit_limit INTO c_limit
from demo_customers cust
where customer_id = custID;
select * from demo_orders where CUSTOMER_ID = custID;
dbms_output.Put_line(c_limit);
END;
If you are using a SQL SELECT statement within an anonymous block (in PL/SQL - between the BEGIN and the END keywords) you must select INTO something so that PL/SQL can utilize a variable to hold your result from the query. It is important to note here that if you are selecting multiple columns, (which you are by "SELECT *"), you must specify multiple variables or a record to insert the results of your query into.
for example:
SELECT 1
INTO v_dummy
FROM dual;
SELECT 1, 2
INTO v_dummy, v_dummy2
FROM dual;
It is also worth pointing out that if your SELECT * FROM.... will return multiple rows, PL/SQL will throw an error. You should only expect to retrieve 1 row of data from a SELECT INTO.
Looks like the error is from the second select query.
select * from demo_orders where CUSTOMER_ID = custID;
PL-SQL won't allow a standalone sql select query for info.
http://pls-00428.ora-code.com/
You need to do some operation with the second select query
I'm sure this is something simple, but I'm really new to PL/SQL and this has me stuck.
I've written a simple stored procedure to return a few values about a customer. Right off the bat, the %rowtype's are not coming up as reserved keywords but the compiler isn't flagging those as errors.
It is, however, ignoring the entire SQL statement flagging the line FROM demo_customers as too many values. Even if I try reducing it to only select one column it still gives me the same error.
create or replace
PROCEDURE GETCUSTOMER
(
arg_customerID demo_customers.customer_id%type,
returnRec OUT demo_customers%rowtype
)
AS
BEGIN
SELECT customer_id, cust_first_name, cust_last_name, cust_email
INTO returnRec
FROM demo_customers
WHERE customer_id = arg_customerID ;
END GETCUSTOMER;
If you want to select into a %ROWTYPE record, you'll want to do a SELECT * rather than selecting individual columns
create or replace
PROCEDURE GETCUSTOMER
(
arg_customerID demo_customers.customer_id%type,
returnRec OUT demo_customers%rowtype
)
AS
BEGIN
SELECT *
INTO returnRec
FROM demo_customers
WHERE customer_id = arg_customerID ;
END GETCUSTOMER;
If you select 4 columns explicitly, Oracle expects you to have 4 variables to select those values into.
I am having a bit of trouble with a select into insert across a dblink in oracle 10. I am using the following statement:
INSERT INTO LOCAL.TABLE_1 ( COL1, COL2)
SELECT COL1, COL2
FROM REMOTE.TABLE1#dblink s
WHERE COL1 IN ( SELECT COL1 FROM WORKING_TABLE)
When I run the statement the following is what gets run against the remote server on the DB Link:
SELECT /*+ OPAQUE_TRANSFORM */ "COL1", "COL2"
FROM "REMOTE"."TABLE1" "S"
If I run the select only and do not do the insert into the following is run:
SELECT /*+ */ "A1"."COL1"
, "A1"."COL2"
FROM "REMOTE"."TABLE1" "A1"
WHERE "A1"."COL1" =
ANY ( SELECT "A2"."COL1"
FROM "LOCAL"."TABLE1"#! "A2")
The issue is in the insert case the enitre table is being pulled across the dblink and then limited localy which takes a fair bit of time given the table size. Is there any reason adding the insert would change the behavior in this manner?
You may want to use the driving_site hint. There is a good explanation here:
http://www.dba-oracle.com/t_sql_dblink_performance.htm
When it comes to DML, oracle chooses to ignore any driving_site hint and executes the statement at the target site. So I doubt if you would be able to change that (even using WITH approach described above). A possible workaround is you can create a synonym for LOCAL.TABLE1 on the remote database and use the same in your INSERT statement.
Leveraging the WITH clause could optimize your retrieval of your working set:
WITH remote_rows AS
(SELECT /*+DRIVING_SITE(s)*/COL1, COL2
FROM REMOTE.TABLE1#dblink s
WHERE COL1 IN ( SELECT COL1 FROM WORKING_TABLE))
INSERT INTO LOCAL.TABLE_1 ( COL1, COL2)
SELECT COL1, COL2
FROM remote_rows
Oracle will ignore the driving_site hint for insert statements, as DML is always executed locally. The way to do this is to create a cursor with the driving site hint, and then loop through the cursor with a bulkcollect/forall and insert into the target local table.
How big is WORKING_TABLE ?
If it is small enough, you could try selecting from work_table into a collection, and then passing the elements of that collect as elements in an IN list.
declare
TYPE t_type IS TABLE OF VARCHAR2(60);
v_coll t_type;
begin
dbms_application_info.set_module('TEST','TEST');
--
select distinct object_type
bulk collect into v_coll
from user_objects;
--
IF v_coll.count > 20 THEN
raise_application_error(-20001,'You need '||v_coll.count||' elements in the IN list');
ELSE
v_coll.extend(20);
END IF;
insert into abc (object_type, object_name)
select object_type, object_name
from user_objects#tmfprd
where object_type in
(v_coll(1), v_coll(2), v_coll(3), v_coll(4), v_coll(5),
v_coll(6), v_coll(7), v_coll(8), v_coll(9), v_coll(10),
v_coll(11), v_coll(12), v_coll(13), v_coll(14), v_coll(15),
v_coll(16), v_coll(17), v_coll(18), v_coll(19), v_coll(20)
);
--
dbms_output.put_line(sql%rowcount);
end;
/
Insert into zith cardinality hint seems to work in 11.2
INSERT /*+ append */
INTO MIG_CGD30_TEST
SELECT /*+ cardinality(ZFD 400000) cardinality(CGD 60000000)*/
TRIM (CGD.NUMCPT) AS NUMCPT, TRIM (ZFD.NUMBDC_NEW) AS NUMBDC
FROM CGD30#DBL_MIG_THALER CGD,
ZFD10#DBL_MIG_THALER ZFD,
EVD01_ADS_DR3W2 EVD