I have a list of people and I want to create view for each person.
If I Have 1 person, my view would be:
CREATE VIEW PersonInfo AS (
SELECT * FROM People WHERE id = 1000
);
But in fact, I have thousands of people, I want to create a stored procedure in Oracle to create view for each person, But View names are duplicated when I use it. How can I handle that problem?
Thank you for helping in advance.
Your aim is interesting(presumably a related with training but not a real-world scenario), but a dynamic solution would be handled with a for loop by using EXECUTE IMMEDIATE of PL/SQL such as
SQL> CREATE OR REPLACE PROCEDURE Crt_People_Views AS
BEGIN
FOR p IN ( SELECT id FROM People )
LOOP
EXECUTE IMMEDIATE 'CREATE OR REPLACE VIEW PersonInfo_'||p.id
||' AS SELECT * FROM People WHERE id = '||p.id;
END LOOP;
END;
/
SQL> EXEC Crt_People_Views; -- call the proc. which will create the desired views
What problem are you trying to solve by creating a view for every person?
Would it make more sense to create a single view that takes a parameter (person_id)?
Something like this?
CREATE OR REPLACE VIEW VIEW_ABC (parm1 INTEGER) AS
SELECT *
FROM XYZ
WHERE ….
Call like this.
Then, all we need do is,
SELECT *
FROM VIEW_ABC (101)
/
No probs. with bind variables. Nicely integrated as one would expect.
Related
I am trying to understand what steps I need to undertake in order to move a stored procedure from one schema and into another. The schema that this is currently sitting in is going to be made redundant and I have been asked to move all tables and procedures. I have no trouble with tables but never done anything with procedures hence want to make sure I don't miss anything out.
What I have currently done is look through the procedure and made a list of what its actually doing i.e. dropping/creating and inserting data into tables.
After this I wasn't sure if it was just a case of copying the procedure code and then creating a new procedure on the new schema with the same code and then compiling it.
I would really appreciate it if somebody could advise if I am missing anything in the steps that I am undertaking just to ensure I don't mess things up.
There is no way to "move" an object from one schema to another.
The only practible way I see here is copying the source code and then executing it in the new schema. As #pmdba wrote as comment, you should watch out for schema names like "MYSCHEMA"."TABLENAME" and other references.
If you got too much to copy you may consider writing a block where you automatically read the data of the old schema and create it automatically in the new one.
You can get the data of (nearly) everything with, i.e. procedures:
select * from all_source where owner = 'OLDSCHEMANAME' and type = 'PROCEDURE';
and use it like this:
begin
....
select listagg(text, '') within group (order by line) into proc_code
from all_source
where owner = 'OLDSCHEMANAME'
and type = 'PROCEDURE'
group by name;
execute immediate 'create or replace ' || proc_code; -- perhaps you need to remove the last ';' here
...
end;
Please note that this code is only meant as hint and doesn't need to be taken exactly that way. Also, you may still get errors due to non existing objects, wrong schema references etc..
To get the ddl of a table one may use select dbms_metadata.get_ddl('TABLE','Table_name','Schema_Name') from dual;.
By googling dbms_metadata.get_ddl you might get more info on the DBMS_METADATA-package and how to use it correctly.
As already stated, there is no mechanism to copy one object ( procedure , function or package, etc ) to another schema. One alternative is using all_source, but I prefer DBMS_METADATA because allows you to transfer all dependencies, like for example privileges. Imagine I need to copy a procedure but I need to keep the privileges, with this package I can get everything.
Example
SQL> create procedure myschema1.my_procedure ( p1 number )
2 as
3 var1 number := p1;
4 begin
5 select 1 into var1 from dual;
6 end;
7 /
Procedure created.
SQL> grant execute on myschema1.my_procedure to myuser ;
Grant succeeded.
Now, let's imagine we want to copy the procedure and its privileges to another schema
SQL> set long 99999999 set lines 200 pages 400
SQL> select dbms_metadata.get_ddl('PROCEDURE','MY_PROCEDURE','MYSCHEMA1') from dual ;
DBMS_METADATA.GET_DDL('PROCEDURE','MY_PROCEDURE','MYSCHEMA1')
--------------------------------------------------------------------------------
CREATE OR REPLACE EDITIONABLE PROCEDURE "MYSCHEMA1"."MY_PROCEDURE" ( p1 number )
as
var1 number := p1;
begin
select 1 into var1 from dual;
end;
But, imagine you don't want quotation and neither the editionable argument
SQL> select
replace(dbms_metadata.get_ddl('PROCEDURE','MY_PROCEDURE','MYSCHEMA1','11.2.0'),'"','') as ddl from dual ;
DDL
--------------------------------------------------------------------------------
CREATE OR REPLACE PROCEDURE MYSCHEMA1.MY_PROCEDURE ( p1 number )
as
var1 number := p1;
begin
select 1 into var1 from dual;
end;
Then to get the final command with the new schema owner, we use regexp_replace to replace the first occurrence
SQL> select regexp_replace(replace(dbms_metadata.get_ddl('PROCEDURE','MY_PROCEDURE','MYSCHEMA1','11.2.0'),'"',''),'MYSCHEMA1','MYSCHEMA2',1,1)
2 as ddl from dual ;
DDL
--------------------------------------------------------------------------------
CREATE OR REPLACE PROCEDURE MYSCHEMA2.MY_PROCEDURE ( p1 number )
as
var1 number := p1;
begin
select 1 into var1 from dual;
end;
Finally, we can get all privileges by
SQL> select dbms_metadata.get_dependent_ddl( 'OBJECT_GRANT' , 'MY_PROCEDURE' , 'MYSCHEMA1' ) from dual ;
DBMS_METADATA.GET_DEPENDENT_DDL('OBJECT_GRANT','MY_PROCEDURE','MYSCHEMA1')
--------------------------------------------------------------------------------
GRANT EXECUTE ON "MYSCHEMA1"."MY_PROCEDURE" TO "MYUSER"
Remember to apply at session level before to start some settings to enhance dbms_metadata output:
begin
DBMS_METADATA.set_transform_param (DBMS_METADATA.session_transform, 'SQLTERMINATOR', true);
DBMS_METADATA.set_transform_param (DBMS_METADATA.session_transform, 'PRETTY', true);
end;
I have found this very interesting article: Refactor a PL/pgSQL function to return the output of various SELECT queries
from Erwin Brandstetter which describes how to return all columns of various tables with only one function:
CREATE OR REPLACE FUNCTION data_of(_table_name anyelement, _where_part text)
RETURNS SETOF anyelement AS
$func$
BEGIN
RETURN QUERY EXECUTE
'SELECT * FROM ' || pg_typeof(_table_name)::text || ' WHERE ' || _where_part;
END
$func$ LANGUAGE plpgsql;
Call:
SELECT * FROM data_of(NULL::tablename,'1=1 LIMIT 1');
This works pretty well. I need a very similar solution but for getting data from a table on a different database via dblink. That means the call NULL::tablename will fail since the table does not exists on the database where the call is made. I wonder how to make this work. Any try to connect inside of the function via dblink to a different database failed to get the result of NULL::tablename. It seems the polymorph function needs a polymorph parameter which creates the return type of the function implicit.
I would appreciate very much if anybody could help me.
Thanks a lot
Kind regards
Brian
it seems this request is more difficult to explain than I thought it is. Here is a second try with a test setup:
Database 1
First we create a test table with some data on database 1:
CREATE TABLE db1_test
(
id integer NOT NULL,
txt text
)
WITH (
OIDS=TRUE
);
INSERT INTO db1_test (id, txt) VALUES(1,'one');
INSERT INTO db1_test (id, txt) VALUES(2,'two');
INSERT INTO db1_test (id, txt) VALUES(3,'three');
Now we create the polymorph function on database 1:
-- create a polymorph function with a polymorph parameter "_table_name" on database 1
-- the return type is set implicit by calling the function "data_of" with the parameter "NULL::[tablename]" and a where part
CREATE OR REPLACE FUNCTION data_of(_table_name anyelement, _where_part text)
RETURNS SETOF anyelement AS
$func$
BEGIN
RETURN QUERY EXECUTE
'SELECT * FROM ' || pg_typeof(_table_name)::text || ' WHERE ' || _where_part;
END
$func$ LANGUAGE plpgsql;
Now we make test call if everything works as aspected on database 1
SELECT * FROM data_of(NULL::db1_test, 'id=2');
It works. Please notice I do NOT specify any columns of the table db1_test. Now we switch over to database 2.
Database 2
Here I need to make exactly the same call to data_of from database 1 as before and although WITHOUT knowing the columns of the selected table at call time. Unfortunatly this is not gonna work, the only call which works is something like that:
SELECT
*
FROM dblink('dbname=[database1] port=[port] user=[user] password=[password]'::text, 'SELECT * FROM data_of(NULL::db1_test, \'id=2\')'::text)
t1(id integer, txt text);
Conclusion
This call works, but as you can see, I need to specify at least once how all the columns look like from the table I want to select. I am looking for any way to bypass this and make it possible to make a call WITHOUT knowing all of the columns from the table on database 1.
Final goal
My final goal is to create a function in database 2 which looks like
SELECT * from data_of_dblink('table_name','where_part')
and which calls internaly data_of() on database1 to make it possible to select a table on a different database with a where part as parameter. It should work like a static view but with the possiblity to pass a where part as parameter.
I am extremly open for suggestions.
Thanks a lot
Brian
This is a simplified version of what I'm trying to do, but let's say I want to select all employees whose manager is in a given department. I could have a SQL query like the following:
SELECT employees.id
FROM employees
WHERE employees.manager IN (SELECT managers.id
FROM managers
WHERE managers.dept = 12)
;
But let's say I want to abstract the manager subquery into a PL/SQL subprogram. How do I do that?
The stored procedures I've worked with (which are mostly written by other developers) tend to have out parameters that get mapped by PHP calling code into a PHP array. I don't really have any experience of calling one stored procedure from another.
What I'd like to do is to have something like this:
SELECT employees.id
FROM employees
WHERE employees.manager IN my_stored_procedure(12)
;
and then my_stored_procedure would output the set of manager IDs for the input parameter (which is 12 in this example).
It is not possible to do exactly as you have posted, but if the selection of managers are not straightforward, you could abstract it through a view or make use of a function that returns a table, like this:
SELECT employees.id
FROM employees
WHERE employees.manager IN (SELECT * from TABLE(get_managers_from_dept(12)));
In this link there is an example of that approach:
Function or Procedure for an IN clause
To Call A stored Proc from another Stored Proc you just need to call it from the Main Proc as mentioned below. This Main Proc can be called /initiated by a PHP Code.
PROCEDURE some_sp
AS
BEGIN
some_other_sp('parm1');
END;
Although less straight-forward, You can do accomplish it by using dynamic sql. This is the structure of your stored procedure. It returns a comma separated list of manager_ids for a given department.
CREATE OR REPLACE FUNCTION my_stored_procedure(
p_dept NUMBER)
RETURN VARCHAR2
IS
v_manager_list VARCHAR2(1000);
BEGIN
SELECT m.id INTO v_manager_list FROM managers m WHERE m.dept = p_dept;
RETURN '('||v_manager_list||')';
EXCEPTION
WHEN NO_DATA_FOUND THEN
RETURN '(NULL)';
END;
/
Now you cannot use this to directly query as ...IN my_stored_procedure(12),
rather you must use a dynamic fetch into a collection.
SET SERVEROUTPUT ON;
DECLARE
TYPE v_emp_type
IS
TABLE OF employees.id%TYPE;
v_emp v_emp_type;
BEGIN
EXECUTE IMMEDIATE 'SELECT employees.id
FROM employees
WHERE employees.id IN '|| my_stored_procedure(100) BULK COLLECT INTO v_emp ;
FOR i IN v_emp.FIRST..v_emp.LAST
LOOP
DBMS_OUTPUT.PUT_LINE(v_emp(i));
END LOOP;
END;
/
All i want is to select all rows from a table and once it is selected and displayed, the data residing in table must get completely deleted. The main concern is that this must be done using sql only and not plsql. Is there a way we can do this inside a package and call that package in a select statement? Please enlighten me here.
Dummy Table is as follows:
ID NAME SALARY DEPT
==================================
1 Sam 50000 HR
2 Max 45000 SALES
3 Lex 51000 HR
4 Nate 66000 DEV
Any help would be greatly appreciated.
select * from Table_Name;
Delete from Table_Name
To select the data from a SQL query try using a pipelined function.
The function can define a cursor for the data you want (or all the data in the table), loop through the cursor piping each row as it goes.
When the cursor loop ends, i.e. all data has been consumed by your query, the function can perform a TRUNCATE table.
To select from the function use the following syntax;
SELECT *
FROM TABLE(my_function)
See the following Oracle documentation for information pipelined functions - https://docs.oracle.com/cd/B28359_01/appdev.111/b28425/pipe_paral_tbl.htm
This cannot be done inside a package, because " this must be done using sql only and not plsql". A package is PL/SQL.
However it is very simple. You want two things: select the table data and delete it. Two things, two commands.
select * from mytable;
truncate mytable;
(You could replace truncate mytable; with delete from mytable;, but this is slower and needs to be followed by commit; to confirm the deletion and end the transaction.)
Without pl/sql it's not possible.
Using pl/sql you can create a function which will populate a row, and then delete
Here is example :
drop table tempdate;
create table tempdate as
select '1' id from dual
UNION
select '2' id from dual
CREATE TYPE t_tf_row AS OBJECT (
id NUMBER
);
CREATE TYPE t_tf_tab IS TABLE OF t_tf_row;
CREATE OR REPLACE FUNCTION get_tab_tf RETURN t_tf_tab PIPELINED AS
PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
FOR rec in (select * from tempdate) LOOP
PIPE ROW(t_tf_row(rec.id));
END LOOP;
delete from tempdate ; commit;
END;
select * from table(get_tab_tf) -- it will populate and then delete
select * from tempdate --you can check here result of deleting
you can use below query
select * from Table_demo delete from Table_demo
The feature you seek is SERIALIZABLE ISOLATION LEVEL. This feature enables repeatable reads, which in particular guarantee that both SELECTand DELETEwill read and process the same identical data.
Example
Alter session set isolation_level=serializable;
select * from tempdate;
--- now insert from other session a new record
delete from tempdate ;
commit;
-- re-query the table old records are deleted, new recor preserved.
I have a view that compares the data in two tables (tableYesterday and tableToday) and outputs a result based on the comparison. Lets call this view: ViewComp.
I have a need to do more than this. WIthin a single view, I actually need to:
create or replace tableToday and pre-populate it.
execute the ViewComp query.
replace tableYesterday with tableToday.
I have researched things like nested views but I could not find a way to perform 1 and 3 from within the view. I would be grateful for any ideas. Thank you.
This is almost certainly a bad idea. Views shouldn't "do" anything.
For those extremely rare cases where this is required, it can be done with the tricks below. You will definitely want to document this code, to explain to other people what you're doing and why.
Sample schema and objects
--Create table.
create table tableYesterday(a number, b number);
--Create abstract data type to hold one row of data to be returned by the view.
create or replace type ViewComp_type is object
(
a number,
b number
);
--Create nested table to hold multiple rows of data to be returned by the view.
create or replace type ViewComp_nt is table of ViewComp_type;
Function to return results
--Create function to return data.
create or replace function ViewComp_function return ViewComp_nt authid current_user as
--This pragma is necessary for a function that will perform DML.
pragma autonomous_transaction;
v_results ViewComp_nt;
v_name_already_exists exception;
pragma exception_init(v_name_already_exists, -955);
begin
--Try to create today's table. Ignore errors if it exists.
begin
execute immediate 'create table tableToday(a number, b number)';
exception when v_name_already_exists then
execute immediate 'truncate table tableToday';
end;
--Populate today's table.
execute immediate 'insert into tableToday values(1,1)';
--Get the difference.
execute immediate q'[
select cast(collect(ViewComp_type(a,b)) as ViewComp_nt)
from
(
select * from tableToday
minus
select * from tableYesterday
)
]' into v_results;
--Remove yesterday's data.
execute immediate 'truncate table tableYesterday';
--Replace it with today's data.
execute immediate 'insert into tableYesterday select * from tableToday';
commit;
--Return the difference.
return v_results;
end;
/
Create the view to return the function's data
create or replace view ViewComp as
select * from table(ViewComp_function);
Test Run
--First execution:
select * from ViewComp;
A B
- -
1 1
--Second execution:
select * from ViewComp;
A B
- -
You can't do such things in view. You can either create PL/SQL procedure to perform your steps or create materialised view.