I need to create a view over a table and would not wish to change view each time table structure changes. Is there any such possibility? any pointers appreciated around this.
If you don't want to specify all the fields of your table, you can define a view with something like select *, even if I don't like such solution, but you always have to rebuild your view after a table alter.
For example:
SQL> create table yourTable ( a number, b number);
Table created.
SQL> insert into yourTable values ( 1, 2);
1 row created.
SQL> insert into yourTable values ( 10, 20);
1 row created.
SQL> create or replace view yourView as select * from yourTable;
View created.
The view works fine:
SQL> select * from yourView;
A B
---------- ----------
1 2
10 20
If you add a column, the view will not show it:
SQL> alter table yourTable add (c number);
Table altered.
SQL> select * from yourView;
A B
---------- ----------
1 2
10 20
You need to rebuild your view to have the new column:
SQL> create or replace view yourView as select * from yourTable;
View created.
SQL> select * from yourView;
A B C
---------- ---------- ----------
1 2
10 20
If you drop a column, your view will become invalid, and you need to rebuild it:
SQL> alter table yourTable drop column c;
Table altered.
SQL> select * from yourView;
select * from yourView
*
ERROR at line 1:
ORA-04063: view "ALEK.YOURVIEW" has errors
SQL> create or replace view yourView as select * from yourTable;
View created.
SQL> select * from yourView;
A B
---------- ----------
1 2
10 20
Related
There is a master table name as projects master
In another form if I select project-1 sl no need to generate from project master(21819001). after successful 1 record save, if I select same project-1
sl no need to generate like 21819002, for next 21819003, so on.
Again after 3 record save if I select projects-3 sl should generate like 41819001 so on.
I am using Oracle Forms 10g.
Here's an example of what you might do - create additional table which contains the most recent SL_NO for each project. That number is created with an autonomous transaction function which makes sure that in a multi-user environment you won't get duplicates.
PROJECTS_MASTER table and some sample data:
SQL> create table projects_master
2 (project number primary key);
Table created.
SQL> insert into projects_master
2 select 21819001 from dual union all
3 select 41819001 from dual;
2 rows created.
This table will contain the most recent SL_NO for each project
SQL> create table projects_sl_no
2 (project number constraint fk_prsl references projects_master (project),
3 sl_no number);
Table created.
The function itself; if row for PAR_PROJECT exists, it'll update it. Otherwise, it'll create a brand new row in PROJECTS_SL_NO table.
SQL> create or replace function f_proj_sl_no
2 (par_project in projects_master.project%type)
3 return projects_sl_no.sl_no%type
4 is
5 pragma autonomous_transaction;
6 l_sl_no projects_sl_no.sl_no%type;
7 begin
8 select b.sl_no + 1
9 into l_sl_no
10 from projects_sl_no b
11 where b.project = par_project
12 for update of b.sl_no;
13
14 update projects_sl_no b
15 set b.sl_no = l_sl_no
16 where b.project = par_project;
17
18 commit;
19 return (l_sl_no);
20 exception
21 when no_data_found
22 then
23 lock table projects_sl_no in exclusive mode;
24
25 insert into projects_sl_no (project, sl_no)
26 values (par_project, par_project);
27
28 commit;
29 return (par_project);
30 end f_proj_sl_no;
31 /
Function created.
Testing:
SQL> select f_proj_sl_no(21819001) sl_no from dual;
SL_NO
----------
21819001
SQL> select f_proj_sl_no(21819001) sl_no from dual;
SL_NO
----------
21819002
SQL> select f_proj_sl_no(21819001) sl_no from dual;
SL_NO
----------
21819003
SQL> select f_proj_sl_no(41819001) sl_no from dual;
SL_NO
----------
41819001
SQL> select * from projects_sl_no;
PROJECT SL_NO
---------- ----------
21819001 21819003
41819001 41819001
SQL>
As you use Forms, you could call the F_PROJ_SL_NO function in WHEN-VALIDATE-RECORD trigger, PRE-INSERT, or even create a before insert database trigger if you're inserting into a more complex table than the ones I created for testing purposes. Anyway, that should be a simpler part of the story.
The situation is that, when I import a file into the database, one of the first thing I usually do is to assign an unique ID for each record.
I normally do below in TSQL
ALTER TABLE MyTable
ADD ID INT IDENTITY(1,1)
I am wondering if there is something similar in PL SQL?
All my search result come back with multiple steps.
Then I'd like to know what PL SQL programmer typically do to ID records after importing a file. Do they do that?
The main purpose for me to ID these records is to trace it back after manipulation/copying.
Again, I understand there is solution there, my further question is whether PL SQL programmer actually do that, or there is other alternative which making this step not necessary in PL SQL?
OK then, as you're on Oracle 11g, there's no identity column there so - back to multiple steps. Here's an example:
I'm creating a table that simulates your imported table:
SQL> create table tab_import as
2 select ename, job, sal
3 from emp
4 where deptno = 10;
Table created.
Add the ID column:
SQL> alter table tab_import add id number;
Table altered.
Create a sequence which will be used to populate the ID column:
SQL> create sequence seq_imp;
Sequence created.
Update current rows:
SQL> update tab_import set
2 id = seq_imp.nextval;
3 rows updated.
Create a trigger which will take care about future inserts (if any):
SQL> create or replace trigger trg_bi_imp
2 before insert on tab_import
3 for each row
4 begin
5 :new.id := seq_imp.nextval;
6 end;
7 /
Trigger created.
Check what's in the table at the moment:
SQL> select * from tab_import;
ENAME JOB SAL ID
---------- --------- ---------- ----------
CLARK MANAGER 2450 1
KING PRESIDENT 5000 2
MILLER CLERK 1300 3
Let's import some more rows:
SQL> insert into tab_import (ename, job, sal)
2 select ename, job, sal
3 from emp
4 where deptno = 20;
3 rows created.
The trigger had silently populated the ID column:
SQL> select * From tab_import;
ENAME JOB SAL ID
---------- --------- ---------- ----------
CLARK MANAGER 2450 1
KING PRESIDENT 5000 2
MILLER CLERK 1300 3
SMITH CLERK 800 4
JONES MANAGER 2975 5
FORD ANALYST 3000 6
6 rows selected.
SQL>
Shortly: you need to
alter table and add the ID column
create a sequence
create a trigger
The end.
The answer given by #Littlefoot would be my recommendation too - but still I thought I could mention the following variant which will work only if you do not intend to add more rows to the table later.
ALTER TABLE MyTable add id number(38,0);
update MyTable set id = rownum;
commit;
My test:
SQL> create table tst as select * from all_tables;
Table created.
SQL> alter table tst add id number(38,0);
Table altered.
SQL> update tst set id = rownum;
3815 rows updated.
SQL> alter table tst add constraint tstPk primary key (id);
Table altered.
SQL>
SQL> select id from tst where id < 15;
ID
----------
1
2
3
4
5
6
7
8
9
10
11
ID
----------
12
13
14
14 rows selected.
But as mentioned initially,- this only fixes numbering for the rows you have at the time of the update - your'e not going to get new id values for new rows anytime later - if you need that, go for the sequence solution.
You can add an id column to a table with a single statement (Oracle 11g, see dbfiddle):
alter table test_
add id raw( 16 ) default sys_guid() ;
Example:
-- create a table without an id column
create table test_ ( str )
as
select dbms_random.string( 'x', 16 )
from dual
connect by level <= 10 ;
select * from test_ ;
STR
ULWL9EXFG6CIO72Z
QOM0W1R9IJ2ZD3DW
YQWAP4HZNQ57C2UH
EETF2AXD4ZKNIBBF
W9SECJYDER793MQW
alter table test_
add id raw( 16 ) default sys_guid() ;
select * from test_ ;
STR ID
ULWL9EXFG6CIO72Z 0x782C6EBCAE2D7B9FE050A00A02005D65
QOM0W1R9IJ2ZD3DW 0x782C6EBCAE2E7B9FE050A00A02005D65
YQWAP4HZNQ57C2UH 0x782C6EBCAE2F7B9FE050A00A02005D65
EETF2AXD4ZKNIBBF 0x782C6EBCAE307B9FE050A00A02005D65
W9SECJYDER793MQW 0x782C6EBCAE317B9FE050A00A02005D65
Testing
-- Are the id values unique and not null? Yes.
alter table test_
add constraint pkey_test_ primary key ( id ) ;
-- When we insert more rows, will the id be generated? Yes.
begin
for i in 1 .. 100
loop
insert into test_ (str) values ( 'str' || to_char( i ) ) ;
end loop ;
end ;
/
select * from test_ order by id desc ;
-- last 10 rows of the result
STR ID
str100 0x782C806E16A5E998E050A00A02005D81
str99 0x782C806E16A4E998E050A00A02005D81
str98 0x782C806E16A3E998E050A00A02005D81
str97 0x782C806E16A2E998E050A00A02005D81
str96 0x782C806E16A1E998E050A00A02005D81
str95 0x782C806E16A0E998E050A00A02005D81
str94 0x782C806E169FE998E050A00A02005D81
str93 0x782C806E169EE998E050A00A02005D81
str92 0x782C806E169DE998E050A00A02005D81
str91 0x782C806E169CE998E050A00A02005D81
Regarding your other questions:
{1} Then I'd like to know what PL SQL programmer typically do to ID records after importing a file. Do they do that? The main purpose for me to ID these records is to trace it back after manipulation/copying.
-> As you know, the purpose of an id is: to identify a row. We don't "do anything to IDs". Thus, your usage of IDs seems legit.
{2} Again, I understand there is solution there, my further question is whether PL SQL programmer actually do that, or there is other alternative which making this step not necessary in PL SQL?
-> Not quite sure what you are asking here. Although there is a ROWID() pseudocolumn (see documentation), we should not use it to identify rows.
"You should not use ROWID as the primary key of a table. If you delete
and reinsert a row with the Import and Export utilities, for example,
then its rowid may change. If you delete a row, then Oracle may
reassign its rowid to a new row inserted later."
Like to get some views from you all, regarding one scenario i'm struggling with currently. Below is a problem statement
I have Table A , B , C
A has below column
user|modified date| wokred_on A | ..some more related to user operation
B has columns
user | modified date | worked on B | ..some other columns
C has columsn
user | modified date | worked on C| ..some other columns
these tables are not have any direct relation except then user.
we have to pull data from these tables for a user between given dates with the count op action or work he has done between a given date range?
my struggle here is these each table has it's own date modified if a date range selected which is not in other column but still i need to pull the data as user has worked on it in between dates.
can it be possible to select these dates and have the in one column so that one can put that in where clause and having outer joins to pull other records ?
Sorry for this big problem statement. any suggestions are very much appreciated
Below is a use case.just extending the assumption given by littlefoot
First, test case:
SQL> create table a (cuser varchar2(10), modified_date date,action );
varchar2 (10) )
Table created.
SQL> create table b (
Table created.cuser varchar2(10), modified_date date,action
varchar2 (10) );
SQL> create table c (cuser varchar2(10), modified_date date,action
varchar2 (10) ));
Table created.
SQL> insert into a values ('lf', date '2018-05-01', 'issue raised');
1 row created.
SQL> insert into a values ('mc', date '2018-05-01', 'issue raised ');
1 row created.
SQL> insert into b values ('lf', date '2018-05-01',issue raised');
1 row created.
SQL> insert into b values ('lf', date '2018-05-01','issue resolved');
1 row created.
SQL> insert into c values ('if', date '2018-05-28',' issue resolved');
1 row created.
SQL> insert into c values ('mc', date '2018-05-13','issue raised');
1 row created.
SQL> insert into c values ('mc', date '2018-05-13','issue resolved');
1 row created.
SQL> alter session set nls_date_format = 'yyyy-mm-dd';
Session altered.
SQL> select * from a;
CUSER MODIFIED_D. ACTION
---------- ----------
lf 2018-05-01 issue raised
mc 2018-05-01 issue raised
SQL> select * from b;
CUSER MODIFIED_D ACTION
---------- ----------. ______________
lf 2018-05-01 issue raised
lf 2018-05-01. issue resolve
SQL> select * from c;
CUSER MODIFIED_D. ACTION
---------- ----------
If 2018-05-28. issue resolve
mc 2018-05-13. issue raised
mc 2018-05-13. issue resolve
CUSER DATE CNT_ISSUE_RAISED CNT_ISSUE_RESOLVED
------ ------- --------------- -------------------
if 2018-05-01 2 1
lf 2018-05-28 0 1
mc 2018-05-01 0 1
mc 2018-05-13 1 1
This is how I understood the question.
First, test case:
SQL> create table a (cuser varchar2(10), modified_date date);
Table created.
SQL> create table b (cuser varchar2(10), modified_date date);
Table created.
SQL> create table c (cuser varchar2(10), modified_date date);
Table created.
SQL> insert into a values ('lf', date '2018-05-01');
1 row created.
SQL> insert into a values ('mc', date '2018-05-15');
1 row created.
SQL> insert into b values ('lf', date '2018-05-07');
1 row created.
SQL> insert into b values ('lf', date '2018-05-08');
1 row created.
SQL> insert into c values ('jw', date '2018-05-28');
1 row created.
SQL> insert into c values ('mc', date '2018-05-13');
1 row created.
SQL> insert into c values ('mc', date '2018-05-22');
1 row created.
SQL> alter session set nls_date_format = 'yyyy-mm-dd';
Session altered.
SQL> select * from a;
CUSER MODIFIED_D
---------- ----------
lf 2018-05-01
mc 2018-05-15
SQL> select * from b;
CUSER MODIFIED_D
---------- ----------
lf 2018-05-07
lf 2018-05-08
SQL> select * from c;
CUSER MODIFIED_D
---------- ----------
jw 2018-05-28
mc 2018-05-13
mc 2018-05-22
Query which returns desired result - number of rows per each user in every table, in desired date period. As I use SQL*Plus, variables are preceded by && to avoid multiple insert requests. In a tool you use, that might be a colon (:).
SQL> select nvl(nvl(a.cuser, b.cuser), c.cuser) cuser,
2 count(distinct a.modified_date) cnt_a,
3 count(distinct b.modified_date) cnt_b,
4 count(distinct c.modified_date) cnt_c
5 from a full outer join b on a.cuser = b.cuser
6 full outer join c on a.cuser = c.cuser
7 where a.modified_date between &&date_from and &&date_to
8 or b.modified_date between &&date_from and &&date_to
9 or c.modified_date between &&date_from and &&date_to
10 group by nvl(nvl(a.cuser, b.cuser), c.cuser)
11 order by 1;
Enter value for date_from: '2018-05-01'
Enter value for date_to: '2018-06-01'
CUSER CNT_A CNT_B CNT_C
---------- ---------- ---------- ----------
jw 0 0 1
lf 1 2 0
mc 1 0 2
SQL>
Let's assume
Table TARGET {
ID IDENTITY ...,
...
JOB_NO NUMBER
}
My question is, how can I generate the JOB_NO (by means of a sequence) so that all inserts that have been committed in a statement have the same job_no.
The output should be something like for the n-th execution of that insert stmt.
ID ... JOB_NO
1 ... 123
2 ... 123
3 ... 123
The following is obviously not working. But what is the correct Oracle syntax?
INSERT INTO TARGET SELECT A.*, B.* FROM my_source_table A, (SELECT x.nextval from dual) B
Thanks a lot
Juergen
You could once select the NEXTVAL for every such insert, which increments the sequence and then use CURRVAL within the INSERT.
Let's say this is your sequence
create sequence seq START WITH 123 ;
Always specify the column names in the INSERT to avoid confusion, don't use select * from
select seq.NEXTVAL FROM DUAL;
INSERT INTO TARGET(JOB_NO,col1,col2,..)
SELECT seq.CURRVAL, a.col1,a.col2 FROM my_source_table A, ..
You should be able to do something like:
insert into target select my_seq.nextval, a.* from source a;
Update based on comment below:
SQL*Plus: Release 12.1.0.2.0 Production on Wed Apr 11 12:48:21 2018
Copyright (c) 1982, 2014, Oracle. All rights reserved.
Connected to:
Oracle Database 12c Standard Edition Release 12.1.0.2.0 - 64bit Production
With the Automatic Storage Management option
SQL> create table a(id number, name varchar2(10));
Table created.
SQL> insert into a values(1,'Larry');
1 row created.
SQL> c/1/2
1* insert into a values(2,'Larry')
SQL> c/Larry/Moe
1* insert into a values(2,'Moe')
SQL> /
1 row created.
SQL> c/2/3
1* insert into a values(3,'Moe')
SQL> c/Moe/Curly
1* insert into a values(3,'Curly')
SQL> /
1 row created.
SQL> commit;
Commit complete.
SQL> select * from a;
ID NAME
---------- ----------
1 Larry
2 Moe
3 Curly
SQL> create table b as select 1 id, a.id id_a, a.name from a where 1=0;
Table created.
SQL> desc b
Name Null? Type
----------------------------------------- -------- ----------------------------
ID NUMBER
ID_A NUMBER
NAME VARCHAR2(10)
SQL> create sequence seq_a;
Sequence created.
SQL> insert into b select seq_a.nextval, a.* from a;
3 rows created.
SQL> select * from b;
ID ID_A NAME
---------- ---------- ----------
1 1 Larry
2 2 Moe
3 3 Curly
I need to select columns from a table Table_A, However there is another table which has the same schema Table_B. The query should determine the from table dynamically. For ex. if Table_A has more rows then use Table_A else use Table_B.
Query something like this
select employee, salary, id from (condition to count rows and select the table )table;
Is this possible without using cursors and EXECUTE IMMEDIATE??.
Normally, you would use dynamic SQL for this sort of thing. That would involve either using the DBMS_SQL package, EXECUTE IMMEDIATE or doing an OPEN <<cursor>> FOR <<SQL statement string>>.
If you really want to use static SQL, you could query both tables and only return one set of results. I cannot envision a situation where this would really make sense but you can certainly do it
Create a FOO and a FOO2 table. FOO2 has two rows to the one row from FOO
SQL> create table foo( col1 number );
Table created.
SQL> create table foo2( col1 number );
Table created.
SQL> insert into foo values( 1 );
1 row created.
SQL> insert into foo2 values( 1 );
1 row created.
SQL> insert into foo2 values( 2 );
1 row created.
Run the query. This will return all the data from FOO2
SQL> ed
Wrote file afiedt.buf
1 select col1
2 from (select the_union.*,
3 max(cnt) over () max_cnt
4 from (select col1, count(*) over () cnt from foo
5 union all
6 select col1, count(*) over () from foo2) the_union)
7* where cnt = max_cnt
SQL> /
COL1
----------
1
2
Insert more rows into FOO. Now the same query will return all the data from FOO
SQL> insert into foo values( 3 );
1 row created.
SQL> insert into foo values( 5 );
1 row created.
SQL> commit;
Commit complete.
SQL> select col1
2 from (select the_union.*,
3 max(cnt) over () max_cnt
4 from (select col1, count(*) over () cnt from foo
5 union all
6 select col1, count(*) over () from foo2) the_union)
7 where cnt = max_cnt;
COL1
----------
1
3
5
As I said, though, I cannot fathom a situation where it would actually make sense to do this.
I am completely guessing at what you are really trying to do, but I am thinking you want to use a synonym. I am guessing that there is some sort of event that triggers when you should be using TableA vs. TableB. Create a synonym "my_table" pointing to TableA and have your view select from "my_table". Then whenever you want your view to point to TableB instead, you just switch your synonym to point to TableB, and you don't have to do anything to the view.
For more info, read about synonyms in the Concepts Guide.