Degree of separation search

I have an application that lets users search based on degree of separation,
so for instance, a user can search for age, hobbies, etc. and limit the
search to just users who are 1 degree separate, 2 degrees separate, or 3
degrees separate.
However as it stands now, searches are taking a long long time because
according to the programmer, the degree of separation is calculated
dynamically upon search, and with a system of about 50,000 users this is
taking way over one minute to execute, causing timeouts in the browser.
Is there a better way to go about doing this type of search? Perhaps using
a scheduler to perform some calculations beforehand so the searches can use
it? Any feedback will be greatly appreciated.
Shabam
Read this article
http://www.sommarskog.se/dyn-search.html
"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:_aCdnc14X62v2bnfRVn-iw@.adelphia.com...
> I have an application that lets users search based on degree of
separation,
> so for instance, a user can search for age, hobbies, etc. and limit the
> search to just users who are 1 degree separate, 2 degrees separate, or 3
> degrees separate.
> However as it stands now, searches are taking a long long time because
> according to the programmer, the degree of separation is calculated
> dynamically upon search, and with a system of about 50,000 users this is
> taking way over one minute to execute, causing timeouts in the browser.
> Is there a better way to go about doing this type of search? Perhaps
using
> a scheduler to perform some calculations beforehand so the searches can
use
> it? Any feedback will be greatly appreciated.
>
|||"Uri Dimant" <urid@.iscar.co.il> wrote in message
news:%23zTvJokHFHA.3624@.tk2msftngp13.phx.gbl...
> Shabam
> Read this article
> http://www.sommarskog.se/dyn-search.html
Thanks for the article link. However the main problem with this search is
the degree of separation search, not the other search criterias. It appears
the application is going through calculating the degree of separation of
each user, then taking the acceptable ones and doing a search on them. The
degree of separation is stored in a function, and thus is being called
hundres, perhaps thousands of times per search. This is why it's taking 1+
minute to do a search. Do you have any ideas/suggestions on how to do this
right?
|||"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:LNednSboiO-g2rnfRVn-iQ@.adelphia.com...
> "Uri Dimant" <urid@.iscar.co.il> wrote in message
> news:%23zTvJokHFHA.3624@.tk2msftngp13.phx.gbl...
> Thanks for the article link. However the main problem with this search is
> the degree of separation search, not the other search criterias. It
> appears
> the application is going through calculating the degree of separation of
> each user, then taking the acceptable ones and doing a search on them.
> The
> degree of separation is stored in a function, and thus is being called
> hundres, perhaps thousands of times per search. This is why it's taking
> 1+
> minute to do a search. Do you have any ideas/suggestions on how to do
> this
> right?
>
There's not much concrete advice we can give without table DDL, sample data
and an explanation of the expected results.
David
|||Basically, this is a spacial problem. What I find most often is that the
developer wants to take the parameters as dynamic, then calculate a
"distance" function between the user with respect to the remaining users
based on the chosen metrics. That is time consuming and expensive.
However, coordinates in "space" are fixed, relativistic effects aside. So,
they are not dynamic and everyone's "position" is known for all metrics.
The problem is that many metrics have differing scales, but we will ignore
that for the moment. So, from beginning geometry, we have for each user,
there position is the set of coordinates, with respect to the origin:
User A: (x1, x2, ..., xn)
User B: (y1, y2, ..., yn)
Their "distance" from the origin is just the Pythagorean Theorem: a^2 + b^2
= c^2, but in N dimensions. The "distance" of all users from a specific one
is just a change of coordinates such that the specific user is put at the
origin:
User A, new coordinates: (x1 - x1, x2 - x2, ..., xn - xn), which is 0 and
what we wanted. For all other users, with respect to the specific user:
User B, new coordinates: (y1 - x1, y2 - x2, ..., yn - xn).
Now, the "distance" from the specific user to any other, in that reference
frame, is just the multi-dimensional, Pythagorean Theorem:
[(y1 - x1)^2 + (y2 - x2)^2 + ... + (yn - xn)^2]^1/2 = distance.
This outlines a multi-dimensional sphere, centered on the specific user.
The point is that everyone's position in space is know with respect to a
common origin and can be calculated beforehand and saved. Now, if you know
my position, you know my direction from the origin, then all users that are
a similar distance from the origin as I am, and in the general direction as
me, must be near me. This logic will produce a subset. Depending on how
restrictive you need to be, like top 100, top 10, top 5, etc., you could
create a general list of others that are near enough to calculate the
specific value without having to calculate it for everyone.
Say you need the 10 closest. Then with a set of, say 100, that where in my
general direction, you could quickly calculate the distance function above
for a mere 100 or so others and come up with the 10 closest, orders of
magnitude quicker than you could if you calculated the distance for
everyone.
Hope this helps.
Sincerely,
Anthony Thomas

"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:LNednSboiO-g2rnfRVn-iQ@.adelphia.com...
"Uri Dimant" <urid@.iscar.co.il> wrote in message
news:%23zTvJokHFHA.3624@.tk2msftngp13.phx.gbl...
> Shabam
> Read this article
> http://www.sommarskog.se/dyn-search.html
Thanks for the article link. However the main problem with this search is
the degree of separation search, not the other search criterias. It appears
the application is going through calculating the degree of separation of
each user, then taking the acceptable ones and doing a search on them. The
degree of separation is stored in a function, and thus is being called
hundres, perhaps thousands of times per search. This is why it's taking 1+
minute to do a search. Do you have any ideas/suggestions on how to do this
right?
|||However as it stands now, searches are taking a long long time because
according to the programmer, the degree of separation is calculated
dynamically upon search, and with a system of about 50,000 users this
is
taking way over one minute to execute, causing timeouts in the browser
Have you tried to increase the timeout value?
Madhivanan
|||See http://groups.google.co.uk/groups?q=nearestExamplar for
further discussion along the lines of what Anthony has said.
Steve Kass
Drew University
Shabam wrote:

>I have an application that lets users search based on degree of separation,
>so for instance, a user can search for age, hobbies, etc. and limit the
>search to just users who are 1 degree separate, 2 degrees separate, or 3
>degrees separate.
>However as it stands now, searches are taking a long long time because
>according to the programmer, the degree of separation is calculated
>dynamically upon search, and with a system of about 50,000 users this is
>taking way over one minute to execute, causing timeouts in the browser.
>Is there a better way to go about doing this type of search? Perhaps using
>a scheduler to perform some calculations beforehand so the searches can use
>it? Any feedback will be greatly appreciated.
>
>
|||Thanks for the reply, but I think there's a misunderstanding here. When I
say degree of separation, I don't mean separation by physical distance, but
by friendship. For instance, A knows B, and B knows C. A doesn't know C.
In this case the relationship would be:
A <-> B <-> C
B would be a first degree friend of A, and C would be a second degree friend
of A, and so on.
The search is limiting based on this type of degree of separation.
|||Yes, I realize the answer I gave you was generic and mathematically based;
however, the logic is the same. For each user, you know there first level
acquantinces, etc., etc. This shouldn't change.
The only thing that is dynamic is which metrics to use for each search. If
you try to recompute it for each query, danamically, this becomes an M x N x
(N - 1) computation. As N or M gets large, this WILL NOT BE LINEAR; thus,
it does NOT scale well.
That, my friend, is a poorly written application and I wouldn't allow into
production. Add just 10% more users and it will bring your system to a
screetching halt!
Tell your "developer" to go back to school and learn what "good" code looks
like.
Sincerely,
Anthony Thomas

"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:O-idnU8g8Imw4bjfRVn-1w@.adelphia.com...
Thanks for the reply, but I think there's a misunderstanding here. When I
say degree of separation, I don't mean separation by physical distance, but
by friendship. For instance, A knows B, and B knows C. A doesn't know C.
In this case the relationship would be:
A <-> B <-> C
B would be a first degree friend of A, and C would be a second degree friend
of A, and so on.
The search is limiting based on this type of degree of separation.
|||"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:O-idnU8g8Imw4bjfRVn-1w@.adelphia.com...
> Thanks for the reply, but I think there's a misunderstanding here. When I
> say degree of separation, I don't mean separation by physical distance,
> but
> by friendship. For instance, A knows B, and B knows C. A doesn't know C.
> In this case the relationship would be:
> A <-> B <-> C
> B would be a first degree friend of A, and C would be a second degree
> friend
> of A, and so on.
> The search is limiting based on this type of degree of separation.
>
Ok. If you are just looking for a couple of "levels" you can do this pretty
quickly with a join.
There are several tricky problems with storing and sorting this kind of
relationship data, and you still didn't post DDL or sample data, so here's a
simple example:
drop table friend
drop table person
go
create table person
(
name varchar(20) primary key,
favorite_band varchar(50)
)
create table friend
(
friend1 varchar(20) not null references person,
friend2 varchar(20) not null references person,
constraint pk_friends primary key (friend1,friend2)
)
create index ix_friend2 on friend(friend2)
insert into person (name,favorite_band) values ('Joe','Def Leopard')
insert into person (name,favorite_band) values ('Alex','Wham')
insert into person (name,favorite_band) values ('Helmut','David Hasselhoff')
insert into person (name,favorite_band) values ('Dennis','Def Leopard')
insert into friend (friend1,friend2) values ('Joe','Alex')
insert into friend (friend1,friend2) values ('Alex','Joe')
insert into friend (friend1,friend2) values ('Joe','Helmut')
insert into friend (friend1,friend2) values ('Helmut','Joe')
insert into friend (friend1,friend2) values ('Helmut','Dennis')
insert into friend (friend1,friend2) values ('Dennis','Helmut')
insert into friend (friend1,friend2) values ('Dennis','Alex')
insert into friend (friend1,friend2) values ('Alex','Dennis')
'Joe has two tickes to the Def Leopard concert and needs someone to'
go
'with, but being shy he wants to go with a friend or a friend of a friend'
create view friends_and_friends_of_friends
as
select
p0.name,
p0.favorite_band,
p1.name friend_name,
p1.favorite_band friend_favorite_band,
p2.name friend_of_friend_name,
p2.favorite_band friend_of_friend_favorite_band
from
person p0
join friend f1 on p0.name = f1.friend1
join person p1 on f1.friend2 = p1.name
join friend f2 on p1.name = f2.friend1
join person p2 on p2.name = f2.friend2
where
p0.name <> p2.name
This query tells Joe that he can go with Dennis, and that he can get
introduced through either Alex or Helmut.
select *
from friends_and_friends_of_friends
where
name = 'Joe'
and
(
friend_favorite_band = 'Def Leopard'
or
friend_of_friend_favorite_band = 'Def Leopard'
)
David
sql

Degree of separation search

I have an application that lets users search based on degree of separation,
so for instance, a user can search for age, hobbies, etc. and limit the
search to just users who are 1 degree separate, 2 degrees separate, or 3
degrees separate.
However as it stands now, searches are taking a long long time because
according to the programmer, the degree of separation is calculated
dynamically upon search, and with a system of about 50,000 users this is
taking way over one minute to execute, causing timeouts in the browser.
Is there a better way to go about doing this type of search? Perhaps using
a scheduler to perform some calculations beforehand so the searches can use
it? Any feedback will be greatly appreciated.Shabam
Read this article
http://www.sommarskog.se/dyn-search.html
"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:_aCdnc14X62v2bnfRVn-iw@.adelphia.com...
> I have an application that lets users search based on degree of
separation,
> so for instance, a user can search for age, hobbies, etc. and limit the
> search to just users who are 1 degree separate, 2 degrees separate, or 3
> degrees separate.
> However as it stands now, searches are taking a long long time because
> according to the programmer, the degree of separation is calculated
> dynamically upon search, and with a system of about 50,000 users this is
> taking way over one minute to execute, causing timeouts in the browser.
> Is there a better way to go about doing this type of search? Perhaps
using
> a scheduler to perform some calculations beforehand so the searches can
use
> it? Any feedback will be greatly appreciated.
>|||"Uri Dimant" <urid@.iscar.co.il> wrote in message
news:%23zTvJokHFHA.3624@.tk2msftngp13.phx.gbl...
> Shabam
> Read this article
> http://www.sommarskog.se/dyn-search.html
Thanks for the article link. However the main problem with this search is
the degree of separation search, not the other search criterias. It appears
the application is going through calculating the degree of separation of
each user, then taking the acceptable ones and doing a search on them. The
degree of separation is stored in a function, and thus is being called
hundres, perhaps thousands of times per search. This is why it's taking 1+
minute to do a search. Do you have any ideas/suggestions on how to do this
right?|||"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:LNednSboiO-g2rnfRVn-iQ@.adelphia.com...
> "Uri Dimant" <urid@.iscar.co.il> wrote in message
> news:%23zTvJokHFHA.3624@.tk2msftngp13.phx.gbl...
> Thanks for the article link. However the main problem with this search is
> the degree of separation search, not the other search criterias. It
> appears
> the application is going through calculating the degree of separation of
> each user, then taking the acceptable ones and doing a search on them.
> The
> degree of separation is stored in a function, and thus is being called
> hundres, perhaps thousands of times per search. This is why it's taking
> 1+
> minute to do a search. Do you have any ideas/suggestions on how to do
> this
> right?
>
There's not much concrete advice we can give without table DDL, sample data
and an explanation of the expected results.
David|||Basically, this is a spacial problem. What I find most often is that the
developer wants to take the parameters as dynamic, then calculate a
"distance" function between the user with respect to the remaining users
based on the chosen metrics. That is time consuming and expensive.
However, coordinates in "space" are fixed, relativistic effects aside. So,
they are not dynamic and everyone's "position" is known for all metrics.
The problem is that many metrics have differing scales, but we will ignore
that for the moment. So, from beginning geometry, we have for each user,
there position is the set of coordinates, with respect to the origin:
User A: (x1, x2, ..., xn)
User B: (y1, y2, ..., yn)
Their "distance" from the origin is just the Pythagorean Theorem: a^2 + b^2
= c^2, but in N dimensions. The "distance" of all users from a specific one
is just a change of coordinates such that the specific user is put at the
origin:
User A, new coordinates: (x1 - x1, x2 - x2, ..., xn - xn), which is 0 and
what we wanted. For all other users, with respect to the specific user:
User B, new coordinates: (y1 - x1, y2 - x2, ..., yn - xn).
Now, the "distance" from the specific user to any other, in that reference
frame, is just the multi-dimensional, Pythagorean Theorem:
[(y1 - x1)^2 + (y2 - x2)^2 + ... + (yn - xn)^2]^1/2 = distance.
This outlines a multi-dimensional sphere, centered on the specific user.
The point is that everyone's position in space is know with respect to a
common origin and can be calculated beforehand and saved. Now, if you know
my position, you know my direction from the origin, then all users that are
a similar distance from the origin as I am, and in the general direction as
me, must be near me. This logic will produce a subset. Depending on how
restrictive you need to be, like top 100, top 10, top 5, etc., you could
create a general list of others that are near enough to calculate the
specific value without having to calculate it for everyone.
Say you need the 10 closest. Then with a set of, say 100, that where in my
general direction, you could quickly calculate the distance function above
for a mere 100 or so others and come up with the 10 closest, orders of
magnitude quicker than you could if you calculated the distance for
everyone.
Hope this helps.
Sincerely,
Anthony Thomas
"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:LNednSboiO-g2rnfRVn-iQ@.adelphia.com...
"Uri Dimant" <urid@.iscar.co.il> wrote in message
news:%23zTvJokHFHA.3624@.tk2msftngp13.phx.gbl...
> Shabam
> Read this article
> http://www.sommarskog.se/dyn-search.html
Thanks for the article link. However the main problem with this search is
the degree of separation search, not the other search criterias. It appears
the application is going through calculating the degree of separation of
each user, then taking the acceptable ones and doing a search on them. The
degree of separation is stored in a function, and thus is being called
hundres, perhaps thousands of times per search. This is why it's taking 1+
minute to do a search. Do you have any ideas/suggestions on how to do this
right?|||However as it stands now, searches are taking a long long time because
according to the programmer, the degree of separation is calculated
dynamically upon search, and with a system of about 50,000 users this
is
taking way over one minute to execute, causing timeouts in the browser
Have you tried to increase the timeout value?
Madhivanan|||See http://groups.google.co.uk/groups?q=nearestExamplar for
further discussion along the lines of what Anthony has said.
Steve Kass
Drew University
Shabam wrote:

>I have an application that lets users search based on degree of separation,
>so for instance, a user can search for age, hobbies, etc. and limit the
>search to just users who are 1 degree separate, 2 degrees separate, or 3
>degrees separate.
>However as it stands now, searches are taking a long long time because
>according to the programmer, the degree of separation is calculated
>dynamically upon search, and with a system of about 50,000 users this is
>taking way over one minute to execute, causing timeouts in the browser.
>Is there a better way to go about doing this type of search? Perhaps using
>a scheduler to perform some calculations beforehand so the searches can use
>it? Any feedback will be greatly appreciated.
>
>|||Thanks for the reply, but I think there's a misunderstanding here. When I
say degree of separation, I don't mean separation by physical distance, but
by friendship. For instance, A knows B, and B knows C. A doesn't know C.
In this case the relationship would be:
A <-> B <-> C
B would be a first degree friend of A, and C would be a second degree friend
of A, and so on.
The search is limiting based on this type of degree of separation.|||Yes, I realize the answer I gave you was generic and mathematically based;
however, the logic is the same. For each user, you know there first level
acquantinces, etc., etc. This shouldn't change.
The only thing that is dynamic is which metrics to use for each search. If
you try to recompute it for each query, danamically, this becomes an M x N x
(N - 1) computation. As N or M gets large, this WILL NOT BE LINEAR; thus,
it does NOT scale well.
That, my friend, is a poorly written application and I wouldn't allow into
production. Add just 10% more users and it will bring your system to a
screetching halt!
Tell your "developer" to go back to school and learn what "good" code looks
like.
Sincerely,
Anthony Thomas
"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:O-idnU8g8Imw4bjfRVn-1w@.adelphia.com...
Thanks for the reply, but I think there's a misunderstanding here. When I
say degree of separation, I don't mean separation by physical distance, but
by friendship. For instance, A knows B, and B knows C. A doesn't know C.
In this case the relationship would be:
A <-> B <-> C
B would be a first degree friend of A, and C would be a second degree friend
of A, and so on.
The search is limiting based on this type of degree of separation.|||"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:O-idnU8g8Imw4bjfRVn-1w@.adelphia.com...
> Thanks for the reply, but I think there's a misunderstanding here. When I
> say degree of separation, I don't mean separation by physical distance,
> but
> by friendship. For instance, A knows B, and B knows C. A doesn't know C.
> In this case the relationship would be:
> A <-> B <-> C
> B would be a first degree friend of A, and C would be a second degree
> friend
> of A, and so on.
> The search is limiting based on this type of degree of separation.
>
Ok. If you are just looking for a couple of "levels" you can do this pretty
quickly with a join.
There are several tricky problems with storing and sorting this kind of
relationship data, and you still didn't post DDL or sample data, so here's a
simple example:
drop table friend
drop table person
go
create table person
(
name varchar(20) primary key,
favorite_band varchar(50)
)
create table friend
(
friend1 varchar(20) not null references person,
friend2 varchar(20) not null references person,
constraint pk_friends primary key (friend1,friend2)
)
create index ix_friend2 on friend(friend2)
insert into person (name,favorite_band) values ('Joe','Def Leopard')
insert into person (name,favorite_band) values ('Alex','Wham')
insert into person (name,favorite_band) values ('Helmut','David Hasselhoff')
insert into person (name,favorite_band) values ('Dennis','Def Leopard')
insert into friend (friend1,friend2) values ('Joe','Alex')
insert into friend (friend1,friend2) values ('Alex','Joe')
insert into friend (friend1,friend2) values ('Joe','Helmut')
insert into friend (friend1,friend2) values ('Helmut','Joe')
insert into friend (friend1,friend2) values ('Helmut','Dennis')
insert into friend (friend1,friend2) values ('Dennis','Helmut')
insert into friend (friend1,friend2) values ('Dennis','Alex')
insert into friend (friend1,friend2) values ('Alex','Dennis')
'Joe has two tickes to the Def Leopard concert and needs someone to'
go
'with, but being shy he wants to go with a friend or a friend of a friend'
create view friends_and_friends_of_friends
as
select
p0.name,
p0.favorite_band,
p1.name friend_name,
p1.favorite_band friend_favorite_band,
p2.name friend_of_friend_name,
p2.favorite_band friend_of_friend_favorite_band
from
person p0
join friend f1 on p0.name = f1.friend1
join person p1 on f1.friend2 = p1.name
join friend f2 on p1.name = f2.friend1
join person p2 on p2.name = f2.friend2
where
p0.name <> p2.name
This query tells Joe that he can go with Dennis, and that he can get
introduced through either Alex or Helmut.
select *
from friends_and_friends_of_friends
where
name = 'Joe'
and
(
friend_favorite_band = 'Def Leopard'
or
friend_of_friend_favorite_band = 'Def Leopard'
)
David

Degree of separation search

I have an application that lets users search based on degree of separation,
so for instance, a user can search for age, hobbies, etc. and limit the
search to just users who are 1 degree separate, 2 degrees separate, or 3
degrees separate.
However as it stands now, searches are taking a long long time because
according to the programmer, the degree of separation is calculated
dynamically upon search, and with a system of about 50,000 users this is
taking way over one minute to execute, causing timeouts in the browser.
Is there a better way to go about doing this type of search? Perhaps using
a scheduler to perform some calculations beforehand so the searches can use
it? Any feedback will be greatly appreciated.Shabam
Read this article
http://www.sommarskog.se/dyn-search.html
"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:_aCdnc14X62v2bnfRVn-iw@.adelphia.com...
> I have an application that lets users search based on degree of
separation,
> so for instance, a user can search for age, hobbies, etc. and limit the
> search to just users who are 1 degree separate, 2 degrees separate, or 3
> degrees separate.
> However as it stands now, searches are taking a long long time because
> according to the programmer, the degree of separation is calculated
> dynamically upon search, and with a system of about 50,000 users this is
> taking way over one minute to execute, causing timeouts in the browser.
> Is there a better way to go about doing this type of search? Perhaps
using
> a scheduler to perform some calculations beforehand so the searches can
use
> it? Any feedback will be greatly appreciated.
>|||"Uri Dimant" <urid@.iscar.co.il> wrote in message
news:%23zTvJokHFHA.3624@.tk2msftngp13.phx.gbl...
> Shabam
> Read this article
> http://www.sommarskog.se/dyn-search.html
Thanks for the article link. However the main problem with this search is
the degree of separation search, not the other search criterias. It appears
the application is going through calculating the degree of separation of
each user, then taking the acceptable ones and doing a search on them. The
degree of separation is stored in a function, and thus is being called
hundres, perhaps thousands of times per search. This is why it's taking 1+
minute to do a search. Do you have any ideas/suggestions on how to do this
right?|||"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:LNednSboiO-g2rnfRVn-iQ@.adelphia.com...
> "Uri Dimant" <urid@.iscar.co.il> wrote in message
> news:%23zTvJokHFHA.3624@.tk2msftngp13.phx.gbl...
>> Shabam
>> Read this article
>> http://www.sommarskog.se/dyn-search.html
> Thanks for the article link. However the main problem with this search is
> the degree of separation search, not the other search criterias. It
> appears
> the application is going through calculating the degree of separation of
> each user, then taking the acceptable ones and doing a search on them.
> The
> degree of separation is stored in a function, and thus is being called
> hundres, perhaps thousands of times per search. This is why it's taking
> 1+
> minute to do a search. Do you have any ideas/suggestions on how to do
> this
> right?
>
There's not much concrete advice we can give without table DDL, sample data
and an explanation of the expected results.
David|||Basically, this is a spacial problem. What I find most often is that the
developer wants to take the parameters as dynamic, then calculate a
"distance" function between the user with respect to the remaining users
based on the chosen metrics. That is time consuming and expensive.
However, coordinates in "space" are fixed, relativistic effects aside. So,
they are not dynamic and everyone's "position" is known for all metrics.
The problem is that many metrics have differing scales, but we will ignore
that for the moment. So, from beginning geometry, we have for each user,
there position is the set of coordinates, with respect to the origin:
User A: (x1, x2, ..., xn)
User B: (y1, y2, ..., yn)
Their "distance" from the origin is just the Pythagorean Theorem: a^2 + b^2
= c^2, but in N dimensions. The "distance" of all users from a specific one
is just a change of coordinates such that the specific user is put at the
origin:
User A, new coordinates: (x1 - x1, x2 - x2, ..., xn - xn), which is 0 and
what we wanted. For all other users, with respect to the specific user:
User B, new coordinates: (y1 - x1, y2 - x2, ..., yn - xn).
Now, the "distance" from the specific user to any other, in that reference
frame, is just the multi-dimensional, Pythagorean Theorem:
[(y1 - x1)^2 + (y2 - x2)^2 + ... + (yn - xn)^2]^1/2 = distance.
This outlines a multi-dimensional sphere, centered on the specific user.
The point is that everyone's position in space is know with respect to a
common origin and can be calculated beforehand and saved. Now, if you know
my position, you know my direction from the origin, then all users that are
a similar distance from the origin as I am, and in the general direction as
me, must be near me. This logic will produce a subset. Depending on how
restrictive you need to be, like top 100, top 10, top 5, etc., you could
create a general list of others that are near enough to calculate the
specific value without having to calculate it for everyone.
Say you need the 10 closest. Then with a set of, say 100, that where in my
general direction, you could quickly calculate the distance function above
for a mere 100 or so others and come up with the 10 closest, orders of
magnitude quicker than you could if you calculated the distance for
everyone.
Hope this helps.
Sincerely,
Anthony Thomas
"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:LNednSboiO-g2rnfRVn-iQ@.adelphia.com...
"Uri Dimant" <urid@.iscar.co.il> wrote in message
news:%23zTvJokHFHA.3624@.tk2msftngp13.phx.gbl...
> Shabam
> Read this article
> http://www.sommarskog.se/dyn-search.html
Thanks for the article link. However the main problem with this search is
the degree of separation search, not the other search criterias. It appears
the application is going through calculating the degree of separation of
each user, then taking the acceptable ones and doing a search on them. The
degree of separation is stored in a function, and thus is being called
hundres, perhaps thousands of times per search. This is why it's taking 1+
minute to do a search. Do you have any ideas/suggestions on how to do this
right?|||However as it stands now, searches are taking a long long time because
according to the programmer, the degree of separation is calculated
dynamically upon search, and with a system of about 50,000 users this
is
taking way over one minute to execute, causing timeouts in the browser
Have you tried to increase the timeout value?
Madhivanan|||See http://groups.google.co.uk/groups?q=nearestExamplar for
further discussion along the lines of what Anthony has said.
Steve Kass
Drew University
Shabam wrote:
>I have an application that lets users search based on degree of separation,
>so for instance, a user can search for age, hobbies, etc. and limit the
>search to just users who are 1 degree separate, 2 degrees separate, or 3
>degrees separate.
>However as it stands now, searches are taking a long long time because
>according to the programmer, the degree of separation is calculated
>dynamically upon search, and with a system of about 50,000 users this is
>taking way over one minute to execute, causing timeouts in the browser.
>Is there a better way to go about doing this type of search? Perhaps using
>a scheduler to perform some calculations beforehand so the searches can use
>it? Any feedback will be greatly appreciated.
>
>|||Thanks for the reply, but I think there's a misunderstanding here. When I
say degree of separation, I don't mean separation by physical distance, but
by friendship. For instance, A knows B, and B knows C. A doesn't know C.
In this case the relationship would be:
A <-> B <-> C
B would be a first degree friend of A, and C would be a second degree friend
of A, and so on.
The search is limiting based on this type of degree of separation.|||Yes, I realize the answer I gave you was generic and mathematically based;
however, the logic is the same. For each user, you know there first level
acquantinces, etc., etc. This shouldn't change.
The only thing that is dynamic is which metrics to use for each search. If
you try to recompute it for each query, danamically, this becomes an M x N x
(N - 1) computation. As N or M gets large, this WILL NOT BE LINEAR; thus,
it does NOT scale well.
That, my friend, is a poorly written application and I wouldn't allow into
production. Add just 10% more users and it will bring your system to a
screetching halt!
Tell your "developer" to go back to school and learn what "good" code looks
like.
Sincerely,
Anthony Thomas
"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:O-idnU8g8Imw4bjfRVn-1w@.adelphia.com...
Thanks for the reply, but I think there's a misunderstanding here. When I
say degree of separation, I don't mean separation by physical distance, but
by friendship. For instance, A knows B, and B knows C. A doesn't know C.
In this case the relationship would be:
A <-> B <-> C
B would be a first degree friend of A, and C would be a second degree friend
of A, and so on.
The search is limiting based on this type of degree of separation.|||"Shabam" <chalupa@.yomama-nospam.com> wrote in message
news:O-idnU8g8Imw4bjfRVn-1w@.adelphia.com...
> Thanks for the reply, but I think there's a misunderstanding here. When I
> say degree of separation, I don't mean separation by physical distance,
> but
> by friendship. For instance, A knows B, and B knows C. A doesn't know C.
> In this case the relationship would be:
> A <-> B <-> C
> B would be a first degree friend of A, and C would be a second degree
> friend
> of A, and so on.
> The search is limiting based on this type of degree of separation.
>
Ok. If you are just looking for a couple of "levels" you can do this pretty
quickly with a join.
There are several tricky problems with storing and sorting this kind of
relationship data, and you still didn't post DDL or sample data, so here's a
simple example:
drop table friend
drop table person
go
create table person
(
name varchar(20) primary key,
favorite_band varchar(50)
)
create table friend
(
friend1 varchar(20) not null references person,
friend2 varchar(20) not null references person,
constraint pk_friends primary key (friend1,friend2)
)
create index ix_friend2 on friend(friend2)
insert into person (name,favorite_band) values ('Joe','Def Leopard')
insert into person (name,favorite_band) values ('Alex','Wham')
insert into person (name,favorite_band) values ('Helmut','David Hasselhoff')
insert into person (name,favorite_band) values ('Dennis','Def Leopard')
insert into friend (friend1,friend2) values ('Joe','Alex')
insert into friend (friend1,friend2) values ('Alex','Joe')
insert into friend (friend1,friend2) values ('Joe','Helmut')
insert into friend (friend1,friend2) values ('Helmut','Joe')
insert into friend (friend1,friend2) values ('Helmut','Dennis')
insert into friend (friend1,friend2) values ('Dennis','Helmut')
insert into friend (friend1,friend2) values ('Dennis','Alex')
insert into friend (friend1,friend2) values ('Alex','Dennis')
'Joe has two tickes to the Def Leopard concert and needs someone to'
go
'with, but being shy he wants to go with a friend or a friend of a friend'
create view friends_and_friends_of_friends
as
select
p0.name,
p0.favorite_band,
p1.name friend_name,
p1.favorite_band friend_favorite_band,
p2.name friend_of_friend_name,
p2.favorite_band friend_of_friend_favorite_band
from
person p0
join friend f1 on p0.name = f1.friend1
join person p1 on f1.friend2 = p1.name
join friend f2 on p1.name = f2.friend1
join person p2 on p2.name = f2.friend2
where
p0.name <> p2.name
This query tells Joe that he can go with Dennis, and that he can get
introduced through either Alex or Helmut.
select *
from friends_and_friends_of_friends
where
name = 'Joe'
and
(
friend_favorite_band = 'Def Leopard'
or
friend_of_friend_favorite_band = 'Def Leopard'
)
David

Defining sort order using parameter fields.

Hi!

This is my first post at this forum.

I have a parameterfield wich the users can use to enter sortorder to the report. I have then created a formula with this code in it.

if {?sortid} = "1" then ({DMD_VIEW_ERRAND.er_control_date} AND {DMD_VIEW_ERRAND.er_id})
else
if {?sortid} = "2" then ({DMD_VIEW_ERRAND.er_activity_desc} AND {DMD_ERRAND.ER_HANDLERDATA} AND {DMD_VIEW_ERRAND.er_id})


This formula is then added into the record sorting expert.

The problem is there is an error in the formula. I want to order by multiple columns. Is it possible?
If it is, what's wrong with my code?

I'm using crystal XI
Best regards
HeleniusI've solved it.

Here's the code

if {?sortid} = "1" then (CStr({DMD_VIEW_ERRAND.er_control_date_fmt}) + "AND" + {DMD_VIEW_ERRAND.er_id})
else
if {?sortid} = "2" then ({DMD_VIEW_ERRAND.er_activity_desc} + "AND" + {DMD_ERRAND.ER_HANDLERDATA} + "AND" + CStr({DMD_VIEW_ERRAND.er_control_date_fmt}) + "AND" + {DMD_VIEW_ERRAND.er_id})

I had a little convertion problem...

/Helenius|||Noooo, it doesn't seem to be solved after all. The report only sort based by the first column. Any suggestions??

Default Value of Parameter using expression - ERROR!

I am trying to use the following expression to establish the default
value for a parameter:
="SELECT DefLib FROM Users WHERE (UserName = SUBSTRING('" & User!UserID
& "', 6, LEN('" & User!UserID & "') - 5))"
The User!UserID resolves as the domain\username or "AERO\username"
When I run the report with this expression in the default value of the
parameter, I get the error:
An unexpected error occurred in Report Processing.
Input string was in the wrong format.
I can use the following query in SQL Query Analyzer to successfully
return all records (or a specific record if I substitute an actual
username).
SELECT DefLib FROM Users WHERE (UserName = SUBSTRING('Aero\' +
UserName, 6, LEN('Aero\' + UserName) - 5))
The return value DefLib is type Int... The value field for the
parameter is also an integer. Why would I receive this error if the
datatypes are the same?
TIA,
FerdBump
Ferd Biffle wrote:
> I am trying to use the following expression to establish the default
> value for a parameter:
> ="SELECT DefLib FROM Users WHERE (UserName = SUBSTRING('" & User!UserID
> & "', 6, LEN('" & User!UserID & "') - 5))"
> The User!UserID resolves as the domain\username or "AERO\username"
> When I run the report with this expression in the default value of the
> parameter, I get the error:
> An unexpected error occurred in Report Processing.
> Input string was in the wrong format.
> I can use the following query in SQL Query Analyzer to successfully
> return all records (or a specific record if I substitute an actual
> username).
> SELECT DefLib FROM Users WHERE (UserName = SUBSTRING('Aero\' +
> UserName, 6, LEN('Aero\' + UserName) - 5))
> The return value DefLib is type Int... The value field for the
> parameter is also an integer. Why would I receive this error if the
> datatypes are the same?
> TIA,
> Ferd|||Hello Ferd,
have you found a solution for this problem?
Tom

Default value for a image

Hi, i would like to insert a default value for a image column in sql server express. is this possible?

I would like to do this so that when users pull up a record in my web forms there is something to see.
thanksyou can either do this from the backend or front end. in table design view you can set the default vale..from your front end you can check for null and show a default image instead.|||Don't store your images in the database. One main reason is the size of the db will grow quickly. It's almost always better to put them on the server's hard drive. In your database you can store the name of the image and call it that way. Setup a varch column of whatever length you need. To answer your default question...store a default image on the server, "myImage.gif" for example. Then insert this image name into your varchar column when you need the default value.|||::Don't store your images in the database. One main reason is the size of the db will grow
::quickly.

So what?

There are arguments in vfacvour and against storing images in the database, but this one is ridiculous.

You may not realize it, bit 1gb = 1gb. Whether I blow 1gb on a SQL Server database, or in the file syste, does not make a dime of a difference.

And then you ignore a lot of the problems you get yby your approach.

* How do you handle transactional guarantee that all images are deleted when they should be?
* How do you make a coherent backup of all material? Note the word "coherent" here.

What exactly is your problem with having a 2gb SQL database? You use shared hosting on a plan that does make a difference? Get a good host.

default table permissions

Hi there,
How can I give full default permissions to a few users whenever I
create a new table in a database in SQL2000? Thanks
Hi,
You can assign the users to the db_owner role in the database. This should
give them full permission on that database.
In case you want users to have full control of SQL Server, you can assign
the login to the serveradmin role.
Thank you.
Regards,
Karthik
"Tester" wrote:

> Hi there,
> How can I give full default permissions to a few users whenever I
> create a new table in a database in SQL2000? Thanks
>
|||I'm not sure exactly what you mean by 'full default permissions'. If you
want those users to have only SELECT, INSERT, UPDATE and DELETE for all
tables in the database, you can add the users to the db_datareader and
db_datawriter roles.
If you want those users to have SELECT, INSERT, UPDATE and DELETE on only
certain tables, then you'll need to grant those permissions individually. I
suggest you create a role and add the desired users to that role:
EXEC sp_addrole 'FullTableRole'
EXEC sp_addrolemember 'FullTableRole', User1'
EXEC sp_addrolemember 'FullTableRole', User2'
GO
After you create a new table:
GRANT SELECT, INSERT, UPDATE, DELETE ON dbo.MyNewTable TO FullTableRole
Hope this helps.
Dan Guzman
SQL Server MVP
"Tester" <calinguga@.netscape.net> wrote in message
news:1179436343.187305.31290@.w5g2000hsg.googlegrou ps.com...
> Hi there,
> How can I give full default permissions to a few users whenever I
> create a new table in a database in SQL2000? Thanks
>

default table permissions

Hi there,
How can I give full default permissions to a few users whenever I
create a new table in a database in SQL2000? ThanksHi,
You can assign the users to the db_owner role in the database. This should
give them full permission on that database.
In case you want users to have full control of SQL Server, you can assign
the login to the serveradmin role.
Thank you.
Regards,
Karthik
"Tester" wrote:
> Hi there,
> How can I give full default permissions to a few users whenever I
> create a new table in a database in SQL2000? Thanks
>|||I'm not sure exactly what you mean by 'full default permissions'. If you
want those users to have only SELECT, INSERT, UPDATE and DELETE for all
tables in the database, you can add the users to the db_datareader and
db_datawriter roles.
If you want those users to have SELECT, INSERT, UPDATE and DELETE on only
certain tables, then you'll need to grant those permissions individually. I
suggest you create a role and add the desired users to that role:
EXEC sp_addrole 'FullTableRole'
EXEC sp_addrolemember 'FullTableRole', User1'
EXEC sp_addrolemember 'FullTableRole', User2'
GO
After you create a new table:
GRANT SELECT, INSERT, UPDATE, DELETE ON dbo.MyNewTable TO FullTableRole
--
Hope this helps.
Dan Guzman
SQL Server MVP
"Tester" <calinguga@.netscape.net> wrote in message
news:1179436343.187305.31290@.w5g2000hsg.googlegroups.com...
> Hi there,
> How can I give full default permissions to a few users whenever I
> create a new table in a database in SQL2000? Thanks
>

default table permissions

Hi there,
How can I give full default permissions to a few users whenever I
create a new table in a database in SQL2000? ThanksHi,
You can assign the users to the db_owner role in the database. This should
give them full permission on that database.
In case you want users to have full control of SQL Server, you can assign
the login to the serveradmin role.
Thank you.
Regards,
Karthik
"Tester" wrote:

> Hi there,
> How can I give full default permissions to a few users whenever I
> create a new table in a database in SQL2000? Thanks
>|||I'm not sure exactly what you mean by 'full default permissions'. If you
want those users to have only SELECT, INSERT, UPDATE and DELETE for all
tables in the database, you can add the users to the db_datareader and
db_datawriter roles.
If you want those users to have SELECT, INSERT, UPDATE and DELETE on only
certain tables, then you'll need to grant those permissions individually. I
suggest you create a role and add the desired users to that role:
EXEC sp_addrole 'FullTableRole'
EXEC sp_addrolemember 'FullTableRole', User1'
EXEC sp_addrolemember 'FullTableRole', User2'
GO
After you create a new table:
GRANT SELECT, INSERT, UPDATE, DELETE ON dbo.MyNewTable TO FullTableRole
Hope this helps.
Dan Guzman
SQL Server MVP
"Tester" <calinguga@.netscape.net> wrote in message
news:1179436343.187305.31290@.w5g2000hsg.googlegroups.com...
> Hi there,
> How can I give full default permissions to a few users whenever I
> create a new table in a database in SQL2000? Thanks
>

default settings when creating a database

Hello,
Some users create new databases using the enterprise manager console (right
click in the database section and then selecting new database).
Once created this database has default settings like "Auto shrink" checked
or "Auto close" unchecked (in the option tab).
Is there a way to set these default settings so each time a new database is
created it has the right options?
thanks
Yes, set the correct options on the Model database. That database is the
baseline from which all other databases on a server are created.
<grille11@.yahoo.com> wrote in message
news:cjju9f$bb5$1@.reader1.imaginet.fr...
> Hello,
> Some users create new databases using the enterprise manager console
(right
> click in the database section and then selecting new database).
> Once created this database has default settings like "Auto shrink" checked
> or "Auto close" unchecked (in the option tab).
> Is there a way to set these default settings so each time a new database
is
> created it has the right options?
> thanks
>
|||I could have searched a little more for this one I guess. Thanks!
"Adam Machanic" <amachanic@.hotmail._removetoemail_.com> wrote in message
news:OMxDsF9pEHA.2864@.TK2MSFTNGP12.phx.gbl...[vbcol=seagreen]
> Yes, set the correct options on the Model database. That database is the
> baseline from which all other databases on a server are created.
>
> <grille11@.yahoo.com> wrote in message
> news:cjju9f$bb5$1@.reader1.imaginet.fr...
> (right
checked
> is
>

default settings when creating a database

Hello,
Some users create new databases using the enterprise manager console (right
click in the database section and then selecting new database).
Once created this database has default settings like "Auto shrink" checked
or "Auto close" unchecked (in the option tab).
Is there a way to set these default settings so each time a new database is
created it has the right options?
thanksYes, set the correct options on the Model database. That database is the
baseline from which all other databases on a server are created.
<grille11@.yahoo.com> wrote in message
news:cjju9f$bb5$1@.reader1.imaginet.fr...
> Hello,
> Some users create new databases using the enterprise manager console
(right
> click in the database section and then selecting new database).
> Once created this database has default settings like "Auto shrink" checked
> or "Auto close" unchecked (in the option tab).
> Is there a way to set these default settings so each time a new database
is
> created it has the right options?
> thanks
>|||I could have searched a little more for this one I guess. Thanks!
"Adam Machanic" <amachanic@.hotmail._removetoemail_.com> wrote in message
news:OMxDsF9pEHA.2864@.TK2MSFTNGP12.phx.gbl...
> Yes, set the correct options on the Model database. That database is the
> baseline from which all other databases on a server are created.
>
> <grille11@.yahoo.com> wrote in message
> news:cjju9f$bb5$1@.reader1.imaginet.fr...
> > Hello,
> >
> > Some users create new databases using the enterprise manager console
> (right
> > click in the database section and then selecting new database).
> > Once created this database has default settings like "Auto shrink"
checked
> > or "Auto close" unchecked (in the option tab).
> > Is there a way to set these default settings so each time a new database
> is
> > created it has the right options?
> >
> > thanks
> >
> >
>

default rs settings

is there a simple manual how to setup RS.

with the administrators group im able to view my reports. but normal users are not able to view anything. they can enter reporting services, but not open a report.

The answer to your problem is to go into Report Manager, click on the properties tab, and add a New Role Assignment.

In the Group or User name box, type Everyone, and then below that, select Browser.

Click on OK.

You can look thru the BOL to see this also. Also, check out the many ssrs blogs online.

hth

BobP