[ADMIN] need help to write a function in postgresql

[Madhu.Lanka]

Hi Friends



Can u please help to write a function for the following scenario?



I have 3 table's user_roles, principals and roles.

I have to write a function in postgresql which should excepts 2 parameters
(name, password)

With those 2 parameters the query should be executed and return the
result.(Result of the query will be 1 or more rows).

The query is working fine if executed it manually by hardcoding the values
for name and password, but is as to be written in function so that I can
send different values.



"select
u.role_id,u.user_id,p.name,p.creation_date,p.telephone_number,p.email,p.rema
rks,p.city,p.state,p.country,p.postal_address,p.company_name,p.department_na
me,p.contact_person,

p.role_group,p.role_description,p.first_name,p.last_name,p.pincode,p.status,
p.department_id,p.designation_id,r.role_name,r.right_edit,r.right_filter,r.r
ight_search,r.right_browse,

r.right_print,
r.right_download,r.right_admin_user,r.right_image_creator,r.right_vector_dow
nload,r.right_wps,r.right_queries_filter,r.right_google_map,r.right_user_man
agement,

r.right_route_analysis,
r.right_legend,r.right_treeview,r.insert,r.update,r.delete,r.query,r.lock
from user_roles u,.principals p,roles r where p.PRINCIPAL_ID = u.USER_ID and


r.role_id = u.role_id and p.name=? and p.password=?"





Thanks in Advance.



Regards

Madhu.Lanka

[Thomas Kellerer]

Post by Madhu.Lanka
Hi Friends
Can u please help to write a function for the following scenario?
I have 3 table’s user_roles, principals and roles.
I have to write a function in postgresql which should excepts 2 parameters (name, password)
With those 2 parameters the query should be executed and return the result.(Result of the query will be 1 or more rows).
The query is working fine if executed it manually by hardcoding the values for name and password, but is as to be written in function so that I can send different values.
“select u.role_id,u.user_id,p.name,p.creation_date,p.telephone_number,p.email,p.remarks,p.city,p.state,p.country,p.postal_address,p.company_name,p.department_name,p.contact_person,
p.role_group,p.role_description,p.first_name,p.last_name,p.pincode,p.status,p.department_id,p.designation_id,r.role_name,r.right_edit,r.right_filter,r.right_search,r.right_browse,
r.right_print, r.right_download,r.right_admin_user,r.right_image_creator,r.right_vector_download,r.right_wps,r.right_queries_filter,r.right_google_map,r.right_user_management,
r.right_route_analysis, r.right_legend,r.right_treeview,r.insert,r.update,r.delete,r.query,r.lock from user_roles u,.principals p,roles r where p.PRINCIPAL_ID = u.USER_ID and
r.role_id = u.role_id and p.name=? and p.password=?”

Something like this:

create or replace function retrieve_user(uname text, pwd text)
returns table (role_id integer, user_id integer, name text, .... more columns ...)
as
$$
SELECT u.role_id,
u.user_id,
p.name,
p.creation_date,
p.telephone_number,
.... more columns ...
FROM user_roles u,
principals p,
roles r
WHERE p.principal_id = u.user_id
AND r.role_id = u.role_id
AND p.name = $1
AND p.password = $2
$$
language SQL;


Then you can do:

select *
from retrieve_user('foo', 'bar');

Personally I'd prefer to create view that wraps that select statement and then simply do a

select *
from user_view
where name = 'foo'
and password = 'bar'

Regards
Thomas

[Laszlo Nagy]

Post by Thomas Kellerer
select *
from retrieve_user('foo', 'bar');
Personally I'd prefer to create view that wraps that select statement and then simply do a
select *
from user_view
where name = 'foo'
and password = 'bar'

It is also better because with a view, you can also do " name is null ".
But you cannot do that with a function (unless you write unnecessary
circumstancial code.)

[Craig Ringer]

Post by Laszlo Nagy
It is also better because with a view, you can also do " name is null
". But you cannot do that with a function (unless you write
unnecessary circumstancial code.)

While I agree with you on the view - among other things, it lets the
query optimiser push conditions down into the view query - there is a
reasonable answer to the problem of comparing to NULL. Just use IS
DISTINCT FROM, eg:

WHERE name IS DISTINCT FROM _test_variable

"IS DISTINCT FROM" is an equality comparison that treats null as a
comparable value like any other, so "NULL IS DISTINCT FROM NULL" is
false. Very handy.

--
Craig Ringer

[Albe Laurenz]

Post by Madhu.Lanka
Can u please help to write a function for the following scenario?
"select [...] from [...] where [...] and p.name=? and p.password=?"

Don't use "?" for the parameters.
Use "$1" for the first parameter and "$2" for the second.

Yours,
Laurenz Albe