Simple Ruby DB apps/programs

ruby-talk
1

I was wondering if there are some example of small Ruby(1.8.1) Database
Apps/Programs. Preferably using Relational Database such as MySQL(4 or
5) or Oracle.

I’d love to see some example of storing name(first,last),
address(addr1,addr2,city,zip),phone(home,work,mobile), and a photo image.

It took me a while to write it in PHP but perhaps I can do it in Ruby
more cleanly while learning this great language.

Thanks

/useko

2

Useko Netsumi wrote:

I was wondering if there are some example of small Ruby(1.8.1) Database
Apps/Programs. Preferably using Relational Database such as MySQL(4 or
5) or Oracle.

I’d love to see some example of storing name(first,last),
address(addr1,addr2,city,zip),phone(home,work,mobile), and a photo image.

It took me a while to write it in PHP but perhaps I can do it in Ruby
more cleanly while learning this great language.

You should take a look at http://lafcadio.rubyforge.org/. I didn’t try
it yet, but it seems to be a very easy and interesting way to create
small DB applications.

3

I think there are samples in libraries,
and there are samples for sure in ruby-dbi. I think that may help you.
even these :
http://www.ruby-doc.org/articles/index.rb/2003/July/30#95_MysqlDuBois
http://www.ruby-doc.org/articles/index.rb/2003/Mar/29#94_Dbi

may help you. Always look at ruby-doc.org :wink:

···

il Sat, 03 Jan 2004 14:45:12 -0500, Useko Netsumi usenets@yahoo.com ha scritto::

I was wondering if there are some example of small Ruby(1.8.1) Database
Apps/Programs. Preferably using Relational Database such as MySQL(4 or
5) or Oracle.

I’d love to see some example of storing name(first,last),
address(addr1,addr2,city,zip),phone(home,work,mobile), and a photo image.

It took me a while to write it in PHP but perhaps I can do it in Ruby
more cleanly while learning this great language.

4

Useko Netsumi wrote:

I was wondering if there are some example of small Ruby(1.8.1) Database
Apps/Programs. Preferably using Relational Database such as MySQL(4 or
5) or Oracle.

I’d love to see some example of storing name(first,last),
address(addr1,addr2,city,zip),phone(home,work,mobile), and a photo image.

It took me a while to write it in PHP but perhaps I can do it in Ruby
more cleanly while learning this great language.

Thanks

/useko

My favorite DBMS for small client apps is sqlite. No other DB comes
close to it in terms of convenience and speed, as long as you’re not
running a distributed type of an application with hundreds of clients
accessing the database at once. There is no need for a database server
at all. All necessary code for accessing the database is compiled in,
and databases are just plain old files. And it is ACID-compliant.
Check out this ruby extension for it here:

http://sqlite-ruby.sourceforge.net/

Carl

5

Carl Youngblood wrote:

Useko Netsumi wrote:

I was wondering if there are some example of small Ruby(1.8.1)
Database Apps/Programs. Preferably using Relational Database such as
MySQL(4 or 5) or Oracle.

I’d love to see some example of storing name(first,last),
address(addr1,addr2,city,zip),phone(home,work,mobile), and a photo image.

It took me a while to write it in PHP but perhaps I can do it in Ruby
more cleanly while learning this great language.

Thanks

/useko

My favorite DBMS for small client apps is sqlite. No other DB comes
close to it in terms of convenience and speed, as long as you’re not
running a distributed type of an application with hundreds of clients
accessing the database at once. There is no need for a database server
at all. All necessary code for accessing the database is compiled in,
and databases are just plain old files. And it is ACID-compliant. Check
out this ruby extension for it here:

http://sqlite-ruby.sourceforge.net/

Carl

Thanks to all.

Perhaps y’all can give me some advice. My apps are running a web photo
apps with mutiple tables in the database. I do not store the image in
the DB but just the /image/file/path and other textual information such
as location, date, time, who took the pictures, and comment fields.
User(s) can only browse, search, and list the information for now. And,
I do not expect more than 20 users accessing it at any given time. Will
it work with SQLITE? Or do I need MySQL or more advanced(more expensive)
RDBMS to handle those tasks.

Thanks

/useko

6

i use pstore for alot of web stuff - it works fine:

~/eg/ruby > cat photo.rb
require ‘pstore’

class DB
def initialize path = ‘photo.db’
@pstore = PStore.new path
end
def = name, record
address, phone = record

@pstore.transaction do
  @pstore[name] = [address, phone]
end

end
def name
@pstore.transaction(read_only = true){ @pstore[name] }
end
def each(&block)
@pstore.transaction do
@pstore.roots.each{|name| block.call(name, @pstore[name])}
end
end
def << record
first,last,addr1,addr2,city,zip,home,work,mobile = record
name = Name[first, last]
address = Address[addr1,addr2,city,zip]
phone = Phone[home,work,mobile]
self[name] = [address, phone]
end

Name = Struct.new “Name”, :first, :last
Address = Struct.new “Address”, :addr1, :addr2, :city, :zip
Phone = Struct.new “Phone”, :home, :work, :mobile

[Name, Address, Phone].each{|c| class << c; alias new; end}
end

if $0 == FILE
db = DB.new

records = [
%w(john doe foo bar boulder 80304 1 2 3),
%w(jane doe bar foo boulder 80305 3 2 1),
]

records.each{|record| db << record}

john = DB::Name[‘john’, ‘doe’]
jane = DB::Name[‘jane’, ‘doe’]

db.each do |name, address, phone|
printf “name: %s\naddress: %s\nphone: %s\n\n”,
name.inspect, address.inspect, phone.inspect
end

p db[john]
p db[jane]
end

~/eg/ruby > ruby photo.rb

name: #<struct Struct::Name first=“john”, last=“doe”>
address: [#<struct Struct::Address addr1=“foo”, addr2=“bar”, city=“boulder”, zip=“80304”>, #<struct Struct::Phone home=“1”, work=“2”, mobile=“3”>]
phone: nil

name: #<struct Struct::Name first=“jane”, last=“doe”>
address: [#<struct Struct::Address addr1=“bar”, addr2=“foo”, city=“boulder”, zip=“80305”>, #<struct Struct::Phone home=“3”, work=“2”, mobile=“1”>]
phone: nil

[#<struct Struct::Address addr1=“foo”, addr2=“bar”, city=“boulder”, zip=“80304”>, #<struct Struct::Phone home=“1”, work=“2”, mobile=“3”>]
[#<struct Struct::Address addr1=“bar”, addr2=“foo”, city=“boulder”, zip=“80305”>, #<struct Struct::Phone home=“3”, work=“2”, mobile=“1”>]

you can obviously just store the path to the photo this way… the thing with
pstore is that you can tailor the object to meet your needs: perhaps a hash
would be better: it’s up to you. also check out madeleine (on RAA) for this
purpose.

-a

···

On Mon, 5 Jan 2004, Useko Netsumi wrote:

Date: Mon, 05 Jan 2004 19:25:27 -0500
From: Useko Netsumi usenets@yahoo.com
Reply-To: usenets_remove_this@yahoo.com
Newsgroups: comp.lang.ruby
Subject: Re: Simple Ruby DB apps/programs …

Carl Youngblood wrote:

Useko Netsumi wrote:

I was wondering if there are some example of small Ruby(1.8.1)
Database Apps/Programs. Preferably using Relational Database such as
MySQL(4 or 5) or Oracle.

I’d love to see some example of storing name(first,last),
address(addr1,addr2,city,zip),phone(home,work,mobile), and a photo image.

It took me a while to write it in PHP but perhaps I can do it in Ruby
more cleanly while learning this great language.

Thanks

/useko

My favorite DBMS for small client apps is sqlite. No other DB comes
close to it in terms of convenience and speed, as long as you’re not
running a distributed type of an application with hundreds of clients
accessing the database at once. There is no need for a database server
at all. All necessary code for accessing the database is compiled in,
and databases are just plain old files. And it is ACID-compliant. Check
out this ruby extension for it here:

http://sqlite-ruby.sourceforge.net/

Carl

Thanks to all.

Perhaps y’all can give me some advice. My apps are running a web photo
apps with mutiple tables in the database. I do not store the image in
the DB but just the /image/file/path and other textual information such
as location, date, time, who took the pictures, and comment fields.
User(s) can only browse, search, and list the information for now. And,
I do not expect more than 20 users accessing it at any given time. Will
it work with SQLITE? Or do I need MySQL or more advanced(more expensive)
RDBMS to handle those tasks.

Thanks

/useko

–

ATTN: please update your address books with address below!

===============================================================================

EMAIL :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
PHONE :: 303.497.6469
ADDRESS :: E/GC2 325 Broadway, Boulder, CO 80305-3328
STP :: Solar-Terrestrial Physics Data | NCEI
NGDC :: http://www.ngdc.noaa.gov/
NESDIS :: http://www.nesdis.noaa.gov/
NOAA :: http://www.noaa.gov/
US DOC :: http://www.commerce.gov/

The difference between art and science is that science is what we
understand well enough to explain to a computer.
Art is everything else.
– Donald Knuth, “Discover”

/bin/sh -c ‘for l in ruby perl;do $l -e “print "\x3a\x2d\x29\x0a"”;done’
===============================================================================

7

Ara.T.Howard wrote:

···

On Mon, 5 Jan 2004, Useko Netsumi wrote:

Date: Mon, 05 Jan 2004 19:25:27 -0500
From: Useko Netsumi usenets@yahoo.com
Reply-To: usenets_remove_this@yahoo.com
Newsgroups: comp.lang.ruby
Subject: Re: Simple Ruby DB apps/programs …

Carl Youngblood wrote:

Useko Netsumi wrote:

I was wondering if there are some example of small Ruby(1.8.1)
Database Apps/Programs. Preferably using Relational Database such as
MySQL(4 or 5) or Oracle.

I’d love to see some example of storing name(first,last),
address(addr1,addr2,city,zip),phone(home,work,mobile), and a photo image.

It took me a while to write it in PHP but perhaps I can do it in Ruby
more cleanly while learning this great language.

Thanks

/useko

My favorite DBMS for small client apps is sqlite. No other DB comes
close to it in terms of convenience and speed, as long as you’re not
running a distributed type of an application with hundreds of clients
accessing the database at once. There is no need for a database server
at all. All necessary code for accessing the database is compiled in,
and databases are just plain old files. And it is ACID-compliant. Check
out this ruby extension for it here:

http://sqlite-ruby.sourceforge.net/

Carl

Thanks to all.

Perhaps y’all can give me some advice. My apps are running a web photo
apps with mutiple tables in the database. I do not store the image in
the DB but just the /image/file/path and other textual information such
as location, date, time, who took the pictures, and comment fields.
User(s) can only browse, search, and list the information for now. And,
I do not expect more than 20 users accessing it at any given time. Will
it work with SQLITE? Or do I need MySQL or more advanced(more expensive)
RDBMS to handle those tasks.

Thanks

/useko

i use pstore for alot of web stuff - it works fine:

~/eg/ruby > cat photo.rb
require ‘pstore’

class DB
def initialize path = ‘photo.db’
@pstore = PStore.new path
end
def = name, record
address, phone = record

@pstore.transaction do
  @pstore[name] = [address, phone]
end

end
def name
@pstore.transaction(read_only = true){ @pstore[name] }
end
def each(&block)
@pstore.transaction do
@pstore.roots.each{|name| block.call(name, @pstore[name])}
end
end
def << record
first,last,addr1,addr2,city,zip,home,work,mobile = record
name = Name[first, last]
address = Address[addr1,addr2,city,zip]
phone = Phone[home,work,mobile]
self[name] = [address, phone]
end

Name = Struct.new “Name”, :first, :last
Address = Struct.new “Address”, :addr1, :addr2, :city, :zip
Phone = Struct.new “Phone”, :home, :work, :mobile

[Name, Address, Phone].each{|c| class << c; alias new; end}
end

if $0 == FILE
db = DB.new

records = [
%w(john doe foo bar boulder 80304 1 2 3),
%w(jane doe bar foo boulder 80305 3 2 1),
]

records.each{|record| db << record}

john = DB::Name[‘john’, ‘doe’]
jane = DB::Name[‘jane’, ‘doe’]

db.each do |name, address, phone|
printf “name: %s\naddress: %s\nphone: %s\n\n”,
name.inspect, address.inspect, phone.inspect
end

p db[john]
p db[jane]
end

~/eg/ruby > ruby photo.rb

name: #<struct Struct::Name first=“john”, last=“doe”>
address: [#<struct Struct::Address addr1=“foo”, addr2=“bar”, city=“boulder”, zip=“80304”>, #<struct Struct::Phone home=“1”, work=“2”, mobile=“3”>]
phone: nil

name: #<struct Struct::Name first=“jane”, last=“doe”>
address: [#<struct Struct::Address addr1=“bar”, addr2=“foo”, city=“boulder”, zip=“80305”>, #<struct Struct::Phone home=“3”, work=“2”, mobile=“1”>]
phone: nil

[#<struct Struct::Address addr1=“foo”, addr2=“bar”, city=“boulder”, zip=“80304”>, #<struct Struct::Phone home=“1”, work=“2”, mobile=“3”>]
[#<struct Struct::Address addr1=“bar”, addr2=“foo”, city=“boulder”, zip=“80305”>, #<struct Struct::Phone home=“3”, work=“2”, mobile=“1”>]

you can obviously just store the path to the photo this way… the thing with
pstore is that you can tailor the object to meet your needs: perhaps a hash
would be better: it’s up to you. also check out madeleine (on RAA) for this
purpose.

-a

Thanks Ara, I’ll definitely will try your example above. And check out
madeline as well.

One question though, have you tried the pstore for multi-user or this is
mainly for single user only? What happen if 2 or more user accessing the
same db at the same time? Thanks

/useko

8

Useko Netsumi usenets@yahoo.com writes:

Thanks Ara, I’ll definitely will try your example above. And check
out madeline as well.

One question though, have you tried the pstore for multi-user or
this is mainly for single user only? What happen if 2 or more user
accessing the same db at the same time? Thanks

pstore.rb uses File.flock to lock the pstore database. This works if
file.flock works (i.e. it will fail when the pstore database is stored
on NFS).

···

–
matt

9

Date: Tue, 06 Jan 2004 00:18:42 -0500
From: Useko Netsumi usenets@yahoo.com
Reply-To: usenets_remove_this@yahoo.com
Newsgroups: comp.lang.ruby
Subject: Re: Simple Ruby DB apps/programs …

Ara.T.Howard wrote:

Date: Mon, 05 Jan 2004 19:25:27 -0500
From: Useko Netsumi usenets@yahoo.com
Reply-To: usenets_remove_this@yahoo.com
Newsgroups: comp.lang.ruby
Subject: Re: Simple Ruby DB apps/programs …

Carl Youngblood wrote:

Useko Netsumi wrote:

I was wondering if there are some example of small Ruby(1.8.1)
Database Apps/Programs. Preferably using Relational Database such as
MySQL(4 or 5) or Oracle.

I’d love to see some example of storing name(first,last),
address(addr1,addr2,city,zip),phone(home,work,mobile), and a photo image.

It took me a while to write it in PHP but perhaps I can do it in Ruby
more cleanly while learning this great language.

Thanks

/useko

My favorite DBMS for small client apps is sqlite. No other DB comes
close to it in terms of convenience and speed, as long as you’re not
running a distributed type of an application with hundreds of clients
accessing the database at once. There is no need for a database server
at all. All necessary code for accessing the database is compiled in,
and databases are just plain old files. And it is ACID-compliant. Check
out this ruby extension for it here:

http://sqlite-ruby.sourceforge.net/

Carl

Thanks to all.

Perhaps y’all can give me some advice. My apps are running a web photo
apps with mutiple tables in the database. I do not store the image in
the DB but just the /image/file/path and other textual information such
as location, date, time, who took the pictures, and comment fields.
User(s) can only browse, search, and list the information for now. And,
I do not expect more than 20 users accessing it at any given time. Will
it work with SQLITE? Or do I need MySQL or more advanced(more expensive)
RDBMS to handle those tasks.

Thanks

/useko

i use pstore for alot of web stuff - it works fine:

~/eg/ruby > cat photo.rb
require ‘pstore’

class DB
def initialize path = ‘photo.db’
@pstore = PStore.new path
end
def = name, record
address, phone = record

@pstore.transaction do
  @pstore[name] = [address, phone]
end

end
def name
@pstore.transaction(read_only = true){ @pstore[name] }
end
def each(&block)
@pstore.transaction do
@pstore.roots.each{|name| block.call(name, @pstore[name])}
end
end
def << record
first,last,addr1,addr2,city,zip,home,work,mobile = record
name = Name[first, last]
address = Address[addr1,addr2,city,zip]
phone = Phone[home,work,mobile]
self[name] = [address, phone]
end

Name = Struct.new “Name”, :first, :last
Address = Struct.new “Address”, :addr1, :addr2, :city, :zip
Phone = Struct.new “Phone”, :home, :work, :mobile

[Name, Address, Phone].each{|c| class << c; alias new; end}
end

if $0 == FILE
db = DB.new

records = [
%w(john doe foo bar boulder 80304 1 2 3),
%w(jane doe bar foo boulder 80305 3 2 1),
]

records.each{|record| db << record}

john = DB::Name[‘john’, ‘doe’]
jane = DB::Name[‘jane’, ‘doe’]

db.each do |name, address, phone|
printf “name: %s\naddress: %s\nphone: %s\n\n”,
name.inspect, address.inspect, phone.inspect
end

p db[john]
p db[jane]
end

~/eg/ruby > ruby photo.rb

name: #<struct Struct::Name first=“john”, last=“doe”>
address: [#<struct Struct::Address addr1=“foo”, addr2=“bar”, city=“boulder”, zip=“80304”>, #<struct Struct::Phone home=“1”, work=“2”, mobile=“3”>]
phone: nil

name: #<struct Struct::Name first=“jane”, last=“doe”>
address: [#<struct Struct::Address addr1=“bar”, addr2=“foo”, city=“boulder”, zip=“80305”>, #<struct Struct::Phone home=“3”, work=“2”, mobile=“1”>]
phone: nil

[#<struct Struct::Address addr1=“foo”, addr2=“bar”, city=“boulder”, zip=“80304”>, #<struct Struct::Phone home=“1”, work=“2”, mobile=“3”>]
[#<struct Struct::Address addr1=“bar”, addr2=“foo”, city=“boulder”, zip=“80305”>, #<struct Struct::Phone home=“3”, work=“2”, mobile=“1”>]

you can obviously just store the path to the photo this way… the thing with
pstore is that you can tailor the object to meet your needs: perhaps a hash
would be better: it’s up to you. also check out madeleine (on RAA) for this
purpose.

-a

Thanks Ara, I’ll definitely will try your example above. And check out
madeline as well.

One question though, have you tried the pstore for multi-user or this is
mainly for single user only?

i have used it for multi-user in house applications. i seem to remember you
saying this was for a round 20 users or so - in which case it would be fine.
if you want more you really need to go with postgresql and ‘set isolation
level serializable’ or deal with transaction conflicts yourself. pstore uses
flock so it supports single writer many reader semantics. note that this is
the same as sqlite - it too uses flock and coarse grained locking internally.

What happen if 2 or more user accessing the same db at the same time? Thanks

one will block. this is generally pretty easy to deal with by simply
minimizing the amount of time you are writing to the database, for example
use:

value = cgi[‘value’]

pstore.transaction do
pstore[:key] = value
end

vs.

pstore.transaction do
value = cgi[‘value’]
pstore[:key] = value
end

unless you db/updates are very big the time blocked will probably be about
what the connection time would be been if using a rdbms server.

and use read_only = true when possible. note that, if you really want true
concurency your cgi script will become pretty compilcated - especially for
multi page apps which can span several minutes… simply using mysql or
postgresql won’t solve think for you.

i would reccomend this:

  • abstract the database layer as a class which get records by key, adds
    records, deletes records, etc.

  • develop your app using pstore or other embedded db

move to a db server iff throughput becomes a problem. the ability to develop
quickly, back up your db using ‘tar’, move to a new server using ‘scp’, etc.
are real benefits - plus you do not move outside the ruby installation and
need to involve sysads (eek). rdbms are great but sometimes a little
overkill.

you also might want to check out ‘bdb’ which is very good and has transaction
support.

-a

···

On Tue, 6 Jan 2004, Useko Netsumi wrote:

On Mon, 5 Jan 2004, Useko Netsumi wrote:
–

ATTN: please update your address books with address below!

===============================================================================

EMAIL :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
PHONE :: 303.497.6469
ADDRESS :: E/GC2 325 Broadway, Boulder, CO 80305-3328
STP :: Solar-Terrestrial Physics Data | NCEI
NGDC :: http://www.ngdc.noaa.gov/
NESDIS :: http://www.nesdis.noaa.gov/
NOAA :: http://www.noaa.gov/
US DOC :: http://www.commerce.gov/

The difference between art and science is that science is what we
understand well enough to explain to a computer.
Art is everything else.
– Donald Knuth, “Discover”

/bin/sh -c ‘for l in ruby perl;do $l -e “print "\x3a\x2d\x29\x0a"”;done’
===============================================================================

10

Thanks and please forgive my lack of knowledge of pstore.

pstore.rb uses File.flock to lock the pstore database.
So, does this mean that it can ONLY serve one users for add/update
record(s) in the DB and mutli-user for read/search?

Is pstore is widely use? Thanks

/useko

“Matt Armstrong” matt@lickey.com wrote in message
news:877k05io7n.fsf@naz.lickey.com…

···

Useko Netsumi usenets@yahoo.com writes:

Thanks Ara, I’ll definitely will try your example above. And check
out madeline as well.

One question though, have you tried the pstore for multi-user or
this is mainly for single user only? What happen if 2 or more user
accessing the same db at the same time? Thanks

pstore.rb uses File.flock to lock the pstore database. This works if
file.flock works (i.e. it will fail when the pstore database is stored
on NFS).

–
matt

11

Thanks Ara.

What web scripting language do you use to build the apps with pstore? Thanks

“Ara.T.Howard” ahoward@ngdc.noaa.gov wrote in message
news:Pine.LNX.4.44.0401060827110.29083-100000@fattire.ngdc.noaa.gov…

Date: Tue, 06 Jan 2004 00:18:42 -0500
From: Useko Netsumi usenets@yahoo.com
Reply-To: usenets_remove_this@yahoo.com
Newsgroups: comp.lang.ruby
Subject: Re: Simple Ruby DB apps/programs …

Ara.T.Howard wrote:

Date: Mon, 05 Jan 2004 19:25:27 -0500
From: Useko Netsumi usenets@yahoo.com
Reply-To: usenets_remove_this@yahoo.com
Newsgroups: comp.lang.ruby
Subject: Re: Simple Ruby DB apps/programs …

Carl Youngblood wrote:

Useko Netsumi wrote:

I was wondering if there are some example of small Ruby(1.8.1)
Database Apps/Programs. Preferably using Relational Database such as
MySQL(4 or 5) or Oracle.

I’d love to see some example of storing name(first,last),
address(addr1,addr2,city,zip),phone(home,work,mobile), and a photo
image.

It took me a while to write it in PHP but perhaps I can do it in
Ruby
more cleanly while learning this great language.

Thanks

/useko

My favorite DBMS for small client apps is sqlite. No other DB comes
close to it in terms of convenience and speed, as long as you’re not
running a distributed type of an application with hundreds of clients
accessing the database at once. There is no need for a database
server
at all. All necessary code for accessing the database is compiled
in,
and databases are just plain old files. And it is ACID-compliant.
Check
out this ruby extension for it here:

http://sqlite-ruby.sourceforge.net/

Carl

Thanks to all.

Perhaps y’all can give me some advice. My apps are running a web photo
apps with mutiple tables in the database. I do not store the image in
the DB but just the /image/file/path and other textual information
such
as location, date, time, who took the pictures, and comment fields.
User(s) can only browse, search, and list the information for now.
And,
I do not expect more than 20 users accessing it at any given time.
Will
it work with SQLITE? Or do I need MySQL or more advanced(more
expensive)
RDBMS to handle those tasks.

Thanks

/useko

i use pstore for alot of web stuff - it works fine:

~/eg/ruby > cat photo.rb
require ‘pstore’

class DB
def initialize path = ‘photo.db’
@pstore = PStore.new path
end
def = name, record
address, phone = record

@pstore.transaction do
  @pstore[name] = [address, phone]
end

end
def name
@pstore.transaction(read_only = true){ @pstore[name] }
end
def each(&block)
@pstore.transaction do
@pstore.roots.each{|name| block.call(name, @pstore[name])}
end
end
def << record
first,last,addr1,addr2,city,zip,home,work,mobile = record
name = Name[first, last]
address = Address[addr1,addr2,city,zip]
phone = Phone[home,work,mobile]
self[name] = [address, phone]
end

Name = Struct.new “Name”, :first, :last
Address = Struct.new “Address”, :addr1, :addr2, :city, :zip
Phone = Struct.new “Phone”, :home, :work, :mobile

[Name, Address, Phone].each{|c| class << c; alias new; end}
end

if $0 == FILE
db = DB.new

records = [
%w(john doe foo bar boulder 80304 1 2 3),
%w(jane doe bar foo boulder 80305 3 2 1),
]

records.each{|record| db << record}

john = DB::Name[‘john’, ‘doe’]
jane = DB::Name[‘jane’, ‘doe’]

db.each do |name, address, phone|
printf “name: %s\naddress: %s\nphone: %s\n\n”,
name.inspect, address.inspect, phone.inspect
end

p db[john]
p db[jane]
end

~/eg/ruby > ruby photo.rb

name: #<struct Struct::Name first=“john”, last=“doe”>
address: [#<struct Struct::Address addr1=“foo”, addr2=“bar”,
city=“boulder”, zip=“80304”>, #<struct Struct::Phone home=“1”, work=“2”,
mobile=“3”>]
phone: nil

name: #<struct Struct::Name first=“jane”, last=“doe”>
address: [#<struct Struct::Address addr1=“bar”, addr2=“foo”,
city=“boulder”, zip=“80305”>, #<struct Struct::Phone home=“3”, work=“2”,
mobile=“1”>]
phone: nil

[#<struct Struct::Address addr1=“foo”, addr2=“bar”, city=“boulder”,
zip=“80304”>, #<struct Struct::Phone home=“1”, work=“2”, mobile=“3”>]
[#<struct Struct::Address addr1=“bar”, addr2=“foo”, city=“boulder”,
zip=“80305”>, #<struct Struct::Phone home=“3”, work=“2”, mobile=“1”>]

you can obviously just store the path to the photo this way… the
thing with
pstore is that you can tailor the object to meet your needs: perhaps a
hash
would be better: it’s up to you. also check out madeleine (on RAA)
for this
purpose.

-a

Thanks Ara, I’ll definitely will try your example above. And check out
madeline as well.

One question though, have you tried the pstore for multi-user or this is
mainly for single user only?

i have used it for multi-user in house applications. i seem to remember
you
saying this was for a round 20 users or so - in which case it would be
fine.
if you want more you really need to go with postgresql and ‘set isolation
level serializable’ or deal with transaction conflicts yourself. pstore
uses
flock so it supports single writer many reader semantics. note that this
is
the same as sqlite - it too uses flock and coarse grained locking
internally.

What happen if 2 or more user accessing the same db at the same time?
Thanks

one will block. this is generally pretty easy to deal with by simply
minimizing the amount of time you are writing to the database, for example
use:

value = cgi[‘value’]

pstore.transaction do
pstore[:key] = value
end

vs.

pstore.transaction do
value = cgi[‘value’]
pstore[:key] = value
end

unless you db/updates are very big the time blocked will probably be
about
what the connection time would be been if using a rdbms server.

and use read_only = true when possible. note that, if you really want
true
concurency your cgi script will become pretty compilcated - especially for
multi page apps which can span several minutes… simply using mysql or
postgresql won’t solve think for you.

i would reccomend this:

  • abstract the database layer as a class which get records by key, adds
    records, deletes records, etc.

  • develop your app using pstore or other embedded db

move to a db server iff throughput becomes a problem. the ability to
develop
quickly, back up your db using ‘tar’, move to a new server using ‘scp’,
etc.
are real benefits - plus you do not move outside the ruby installation and
need to involve sysads (eek). rdbms are great but sometimes a little
overkill.

you also might want to check out ‘bdb’ which is very good and has
transaction

···

On Tue, 6 Jan 2004, Useko Netsumi wrote:

On Mon, 5 Jan 2004, Useko Netsumi wrote:
support.

-a

ATTN: please update your address books with address below!

============================================================================

EMAIL :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
PHONE :: 303.497.6469
ADDRESS :: E/GC2 325 Broadway, Boulder, CO 80305-3328
STP :: Solar-Terrestrial Physics Data | NCEI
NGDC :: http://www.ngdc.noaa.gov/
NESDIS :: http://www.nesdis.noaa.gov/
NOAA :: http://www.noaa.gov/
US DOC :: http://www.commerce.gov/

The difference between art and science is that science is what we
understand well enough to explain to a computer.
Art is everything else.
– Donald Knuth, “Discover”

/bin/sh -c ‘for l in ruby perl;do $l -e “print
"\x3a\x2d\x29\x0a"”;done’

============================================================================

12

“Useko Netsumi” usenets@yahoo.com writes:

Thanks and please forgive my lack of knowledge of pstore.

pstore.rb uses File.flock to lock the pstore database.

So, does this mean that it can ONLY serve one users for add/update
record(s) in the DB and mutli-user for read/search?

Yes.

Is pstore is widely use? Thanks

The old RAA used a pstore to store the data for every ruby project
listed (maybe the new one does too, I don’t know). It works fine so
long as your data set is not large – it reads the whole data set
into memory and writes it all back out each time it is opened/closed.

···

–
matt

13

Thanks.

By any chance, what web server technology do you use?
Apache/mod_ruby/eruby or other(java,php,etc)? Please advise

“Matt Armstrong” matt@lickey.com wrote in message
news:87r7ydghsg.fsf@naz.lickey.com…

···

“Useko Netsumi” usenets@yahoo.com writes:

Thanks and please forgive my lack of knowledge of pstore.

pstore.rb uses File.flock to lock the pstore database.

So, does this mean that it can ONLY serve one users for add/update
record(s) in the DB and mutli-user for read/search?

Yes.

Is pstore is widely use? Thanks

The old RAA used a pstore to store the data for every ruby project
listed (maybe the new one does too, I don’t know). It works fine so
long as your data set is not large – it reads the whole data set
into memory and writes it all back out each time it is opened/closed.

–
matt

14

Matt Armstrong wrote:

“Useko Netsumi” usenets@yahoo.com writes:

Thanks and please forgive my lack of knowledge of pstore.

pstore.rb uses File.flock to lock the pstore database.

So, does this mean that it can ONLY serve one users for add/update
record(s) in the DB and mutli-user for read/search?

Yes.

Is pstore is widely use? Thanks

The old RAA used a pstore to store the data for every ruby project
listed (maybe the new one does too, I don’t know). It works fine so
long as your data set is not large – it reads the whole data set
into memory and writes it all back out each time it is opened/closed.

These two problems are part of why I wrote fsdb (on RAA, and at
FSDB). The basic idea is that you
select a directory to be your “database”, and FSDB gives you a db object
that has a database interface and accessed that dir and it subdirs:

db = FSDB::Database.new(‘/tmp’)
db[‘foo/bar’] = {:x => 1}
db.edit ‘foo/bar’ do |bar|
bar[:x] += 1 # inside transaction
end
db[‘foo/bar’][:x] # ==> 2

FSDB makes life easy if you have a pre-existing file structure with
various formats, and you want to treat them as a database. You can
define your own mapping from path strings to file formats (e.g., “.txt”
files are read as strings, “.obj” as marshalled objects, etc.;
naturally, you can use regexes.). Also, FSDB is thread-safe and
process-safe.

A quick comparison with PStore:

Like pstore, fsdb is:

  • pure ruby, cross-platform (well, not quite there on windows yet–see
    below)

  • ruby license

  • simple API

  • simple implementation (though less so)

  • transaction based, with abort capability

However, pstore has some drawbacks:

  • not thread-safe (though it is process-safe, as far as flock goes)

  • coarse granularity (transaction applies to whole pstore), does not
    scale well

  • uses marshalling, even if your data is is some other format that
    doesn’t require the overhead of marshalling (e.g., strings, binary data)

Other advantages of fsdb:

  • can use YAML (or other formats) where you want to (e.g., in user
    settings, but perhaps not for large ruby objects or binary data). It’s
    easy to specify a mapping from path patterns to data formats.

  • thread-safe, so you can easily wire it up to a multithreaded server,
    like drb (see examples/server.rb)

  • objects in the database are just files, and so can be manipulated with
    standard command line tools (including rsync, versioning tools, etc.).

  • granularity is up to you: you can have lots of little objects, if you
    want (there are tradeoffs, of course)

  • scales as well as the fs does

  • thoroughly stress-tested, partially unit-tested on linux and solaris.
    On windows, all examples, benchmarks, and tests except the stress test
    (tests/test-concurrency.rb) run correctly with the ruby 1.8.0
    single-click installer edition. (The stress test does run on windows
    with ruby 1.8.1 built with mingw, so I’m itching to get /\ndy’s 1.8.1.)

  • Can select fcntl-based locking (if platform supports it), which should
    allow safe use with NFS mounts on linux

Disadvantages of fsdb:

  • If you want indexes, you need to implement them on top of fsdb. You
    could do:

    db[‘name-index’] = RBTree.new

and define your own methods for adding/removing objects that also
updates the name-index. The name-index maps names (or other keys) to
paths in the db.

  • Likewise, no SQL, out of the box.

  • Efficiency and reliability depends on the fs. (My benchmarks get on
    the order of 1000 transactions per sec on a 3 yr old linux box. Windows
    seems a bit slower…)