fukuoka.ex#11：DB／データサイエンスにコネクトするElixirで発表した資料です

1. Mnesia
2018/6/22

2. •
• Fusic
• Elixir React Golang PHP
• @kobatako_
• @kobatako

3. •
•
• CRUD
•

5. • Mnesia
• Erlang DBMS
• DB
• Schema
•
•

6. •
•
• Mnesia
• Erlang DBMS
• DB
• Schema

8. # iex --sname b --cookie bar
• Node sname a b
• cookie bar
# iex --sname a --cookie bar
Node A
Node B
• Node

9. iex(a@9fa43a09fbea)1> :mnesia.create_schema([node(), :"b@f2209c604096"])
• Schema
Mnesia.b@f2209c604096
Mnesia.a@9fa43a09fbea
• Node A
• Node B
• Node A Node B Schema

10. •
iex(b@f2209c604096)1> Node.list
[:a@9fa43a09fbea]
iex(a@9fa43a09fbea)1> Node.list
[]
iex(a@9fa43a09fbea)2> :mnesia.start
:ok
iex(a@9fa43a09fbea)3> Node.list
[:b@f2209c604096]
• Node A Mnesia
• Node B

11. iex(a@9fa43a09fbea)2> :mnesia.system_info
===> System info in version "4.15.3", debug level = none <===
opt_disc. Directory "/var/workspace/mnesia/data/snameA/Mnesia.a@9fa43a09fbea" is used.
use fallback at restart = true
running db nodes = []
stopped db nodes = [b@f2209c604096,a@9fa43a09fbea]
:no
Node A
• Mnesia
iex(b@f2209c604096)1> :mnesia.system_info
===> System info in version "4.15.3", debug level = none <===
opt_disc. Directory "/var/workspace/mnesia/data/snameB/Mnesia.b@f2209c604096" is used.
use fallback at restart = true
running db nodes = []
stopped db nodes = [b@f2209c604096,a@9fa43a09fbea]
:no
Node B

12. iex(a@9fa43a09fbea)4> :mnesia.start
:ok
iex(a@9fa43a09fbea)5> :mnesia.system_info
===> System info in version "4.15.3", debug level = none <===
opt_disc. Directory "/var/workspace/mnesia/data/snameA/Mnesia.a@9fa43a09fbea" is used.
use fallback at restart = false
running db nodes = [a@9fa43a09fbea]
stopped db nodes = [b@f2209c604096]
master node tables = []
remote = []
ram_copies = []
disc_copies = [schema]
disc_only_copies = []
[{a@9fa43a09fbea,disc_copies}] = [schema]
2 transactions committed, 0 aborted, 0 restarted, 0 logged to disc
0 held locks, 0 in queue; 0 local transactions, 0 remote
0 transactions waits for other nodes: []
:yes
Node A
• Mnesia

13. iex(b@f2209c604096)2> :mnesia.system_info
===> System info in version "4.15.3", debug level = none <===
opt_disc. Directory "/var/workspace/mnesia/data/snameB/Mnesia.b@f2209c604096" is used.
use fallback at restart = true
running db nodes = [a@9fa43a09fbea]
stopped db nodes = [b@f2209c604096]
:no
Node B
Node B Node A Mnesia
• Mnesia

14. iex(b@f2209c604096)6> :mnesia.start
:ok
iex(b@f2209c604096)7> :mnesia.system_info
===> System info in version "4.15.3", debug level = none <===
opt_disc. Directory "/var/workspace/mnesia/data/snameB/Mnesia.b@f2209c604096" is used.
use fallback at restart = false
running db nodes = [a@9fa43a09fbea,b@f2209c604096]
stopped db nodes = []
master node tables = []
remote = []
ram_copies = []
disc_copies = [schema]
disc_only_copies = []
[{a@9fa43a09fbea,disc_copies},{b@f2209c604096,disc_copies}] = [schema]
3 transactions committed, 0 aborted, 0 restarted, 2 logged to disc
0 held locks, 0 in queue; 0 local transactions, 0 remote
0 transactions waits for other nodes: []
:yes
Node B
• Mnesia

15. iex(a@9fa43a09fbea)7> :mnesia.create_table(Employee, [attributes:
[:emp_no, :name, :salary, :sex, :phone, :room_no]])
{:atomic, :ok}
iex(a@9fa43a09fbea)8> :mnesia.system_info
===> System info in version "4.15.3", debug level = none <===
opt_disc. Directory "/var/workspace/mnesia/data/snameA/Mnesia.a@9fa43a09fbea" is used.
use fallback at restart = false
running db nodes = [b@f2209c604096,a@9fa43a09fbea]
stopped db nodes = []
master node tables = []
remote = []
ram_copies = ['Elixir.Employee']
disc_copies = [schema]
disc_only_copies = []
[{a@9fa43a09fbea,disc_copies},{b@f2209c604096,disc_copies}] = [schema]
[{a@9fa43a09fbea,ram_copies}] = ['Elixir.Employee']
3 transactions committed, 0 aborted, 0 restarted, 5 logged to disc
0 held locks, 0 in queue; 0 local transactions, 0 remote
0 transactions waits for other nodes: []
:yes
Node A
Employee
•

16. iex(b@f2209c604096)8> :mnesia.system_info
===> System info in version "4.15.3", debug level = none <===
opt_disc. Directory "/var/workspace/mnesia/data/snameB/Mnesia.b@f2209c604096" is used.
use fallback at restart = false
running db nodes = [a@9fa43a09fbea,b@f2209c604096]
stopped db nodes = []
master node tables = []
remote = ['Elixir.Employee']
ram_copies = []
disc_copies = [schema]
disc_only_copies = []
[{a@9fa43a09fbea,disc_copies},{b@f2209c604096,disc_copies}] = [schema]
[{a@9fa43a09fbea,ram_copies}] = ['Elixir.Employee']
3 transactions committed, 0 aborted, 0 restarted, 5 logged to disc
0 held locks, 0 in queue; 0 local transactions, 0 remote
0 transactions waits for other nodes: []
:yes
Node B
B Employee
•

17. iex(a@9fa43a09fbea)9> :mnesia.create_table(Dept, [attributes: [:id, :name]])
{:atomic, :ok}
iex(a@9fa43a09fbea)10> :mnesia.create_table(Project, [attributes: [:id, :name]])
{:atomic, :ok}
iex(a@9fa43a09fbea)13> :mnesia.create_table(Manager, [type: :bag, attributes:
[:emp, :dept]])
{:atomic, :ok}
iex(a@9fa43a09fbea)14> :mnesia.create_table(AtDep, [attributes: [:emp, :dept_id]])
{:atomic, :ok}
iex(a@9fa43a09fbea)15> :mnesia.create_table(InProj, [type: :bag, attributes:
[:emp, :proj_name]])
{:atomic, :ok}
Node A
type bag ID
set ID
•

18. iex(a@9fa43a09fbea)5> :mnesia.system_info
===> System info in version "4.15.3", debug level = none <===
opt_disc. Directory "/var/workspace/mnesia/data/snameA/Mnesia.a@9fa43a09fbea" is used.
use fallback at restart = false
running db nodes = [b@f2209c604096,a@9fa43a09fbea]
stopped db nodes = []
master node tables = []
remote = []
ram_copies = ['Elixir.AtDep','Elixir.Dept','Elixir.InProj',
'Elixir.Manager','Elixir.Project']
disc_copies = [schema]
disc_only_copies = []
[{a@9fa43a09fbea,disc_copies},{b@f2209c604096,disc_copies}] = [schema]
[{a@9fa43a09fbea,ram_copies}] = ['Elixir.Dept','Elixir.Project',
'Elixir.Manager','Elixir.InProj',
'Elixir.AtDep']
7 transactions committed, 0 aborted, 0 restarted, 17 logged to disc
0 held locks, 0 in queue; 0 local transactions, 0 remote
0 transactions waits for other nodes: []
:yes
Node A
•

19. iex(b@f2209c604096)2> :mnesia.system_info
===> System info in version "4.15.3", debug level = none <===
opt_disc. Directory "/var/workspace/mnesia/data/snameB/Mnesia.b@f2209c604096" is used.
use fallback at restart = false
running db nodes = [a@9fa43a09fbea,b@f2209c604096]
stopped db nodes = []
master node tables = []
remote = ['Elixir.AtDep','Elixir.Dept','Elixir.InProj',
'Elixir.Manager','Elixir.Project']
ram_copies = []
disc_copies = [schema]
disc_only_copies = []
[{a@9fa43a09fbea,disc_copies},{b@f2209c604096,disc_copies}] = [schema]
[{a@9fa43a09fbea,ram_copies}] = ['Elixir.Dept','Elixir.Project',
'Elixir.Manager','Elixir.InProj',
'Elixir.AtDep']
3 transactions committed, 0 aborted, 0 restarted, 17 logged to disc
0 held locks, 0 in queue; 0 local transactions, 0 remote
0 transactions waits for other nodes: []
:yes
Node B
B
•

20. CRUD

21. CRUD
•
• Dirty Operations

23. def insert_emp(emp, dep_id, project_names) do
name = emp[:name]
#
fun = fn() ->
:mnesia.write({Employee, emp[:emp_no], emp[:name], emp[:salary], emp[:sex],
emp[:phone], emp[:room_no]})
at_dep = {AtDep, name, dep_id}
:mnesia.write(at_dep)
mk_proj(name, project_names)
end
#
:mnesia.transaction(fun)
end
insert
•

24. iex(a@9fa43a09fbea)3> insert_emp(%{emp_no: 104732, name: "klacke", salary: 7,
sex: :male, phone: 98108, room_no: {221, 015}}, "B/SFR", [:erlang, :mnesia, :otp])
Node A
insert insert_emp
•
iex(a@9fa43a09fbea)23> :mnesia.transaction(fn -> :mnesia.read({InProj, "klacke"}) end)
{:atomic,
[
{InProj, "klacke", :erlang},
{InProj, "klacke", :mnesia},
{InProj, "klacke", :otp}
]}
iex(a@9fa43a09fbea)24> :mnesia.transaction(fn -> :mnesia.read({Employee, 104732}) end)
{:atomic, [{Employee, 104732, "klacke", 7, :male, 98108, {221, 15}}]}
iex(a@9fa43a09fbea)25> :mnesia.transaction(fn -> :mnesia.read({AtDep, "klacke"}) end)
{:atomic, [{AtDep, "klacke", "B/SFR"}]}

25. #
iex(a@9fa43a09fbea)11> :mnesia.read({Employee, 104732})
** (exit) {:aborted, :no_transaction}
(mnesia) mnesia.erl:351: :mnesia.abort/1
#
iex(a@9fa43a09fbea)11> :mnesia.transaction(fn -> :mnesia.read({Employee, 104732}) end)
{:atomic, [{Employee, 104732, "klacke", 7, :male, 98108, {221, 15}}]}
Node A
read
•

26. iex(b@f2209c604096)17> :mnesia.transaction(fn -> :mnesia.read({InProj, "klacke"}) end)
{:atomic,
[
{InProj, "klacke", :erlang},
{InProj, "klacke", :mnesia},
{InProj, "klacke", :otp}
]}
iex(b@f2209c604096)18> :mnesia.transaction(fn -> :mnesia.read({Employee, 104732}) end)
{:atomic, [{Employee, 104732, "klacke", 7, :male, 98108, {221, 15}}]}
iex(b@f2209c604096)19> :mnesia.transaction(fn -> :mnesia.read({AtDep, "klacke"}) end)
{:atomic, [{AtDep, "klacke", "B/SFR"}]}
Node B
Node A
•

27. Dirty Operations

28. Dirty Operations
iex(a@9fa43a09fbea)5> :mnesia.dirty_read(InProj, "klacke")
[
{InProj, "klacke", :erlang},
{InProj, "klacke", :mnesia},
{InProj, "klacke", :otp}
]
•
iex(a@9fa43a09fbea)32> :mnesia.dirty_write({Project, 1, "project01"})
:ok
iex(a@9fa43a09fbea)33> :mnesia.dirty_read(Project, 1)
[{Project, 1, "project01"}]

29. Dirty Operations
iex(a@9fa43a09fbea)36> :mnesia.dirty_write({Project, 2, "project02"})
:ok
iex(a@9fa43a09fbea)37> :mnesia.dirty_first(Project)
2
iex(a@9fa43a09fbea)38> :mnesia.dirty_next(Project, 2)
1
iex(a@9fa43a09fbea)39> :mnesia.dirty_next(Project, 1)
:”$end_of_table"
key
:”$end_of_table”
•

31. Node A B A
B

32. iex(a@9fa43a09fbea)1> :mnesia.start
:ok
iex(a@9fa43a09fbea)2> :mnesia.system_info
===> System info in version "4.15.3", debug level = none <===
opt_disc. Directory "/var/workspace/mnesia/data/snameA/Mnesia.a@9fa43a09fbea" is used.
use fallback at restart = false
running db nodes = [a@9fa43a09fbea]
stopped db nodes = [b@f2209c604096]
master node tables = []
remote = []
ram_copies = ['Elixir.AtDep','Elixir.Dept','Elixir.Employee',
'Elixir.InProj','Elixir.Manager','Elixir.Project']
disc_copies = [schema]
disc_only_copies = []
[{a@9fa43a09fbea,disc_copies}] = [schema]
[{a@9fa43a09fbea,ram_copies}] = ['Elixir.AtDep','Elixir.Dept','Elixir.InProj',
'Elixir.Project','Elixir.Employee',
'Elixir.Manager']
2 transactions committed, 0 aborted, 0 restarted, 0 logged to disc
0 held locks, 0 in queue; 0 local transactions, 0 remote
0 transactions waits for other nodes: []
:yes
Node A
Mnesia
•

33. #
iex(a@9fa43a09fbea)3> :mnesia.transaction(fn -> :mnesia.read({Employee, 104733}) end)
{:atomic, []}
# insert
iex(a@9fa43a09fbea)4> Sample.insert_emp(%{emp_no: 104732, name: "klacke", salary: 7,
sex: :male, phone: 98108, room_no: {221, 015}}, "B/SFR", [:erlang, :mnesia, :otp])
{:atomic, :ok}
#
iex(a@9fa43a09fbea)5> :mnesia.transaction(fn -> :mnesia.read({Employee, 104732}) end)
{:atomic, [{Employee, 104732, "klacke", 7, :male, 98108, {221, 15}}]}
Node A
insert
•

34. #
iex(b@f2209c604096)2> Node.list
[]
# Mnesia
iex(b@f2209c604096)3> :mnesia.transaction(fn -> :mnesia.read({Employee, 104732}) end)
{:aborted, {:node_not_running, :b@f2209c604096}}
# Mnesia
iex(b@f2209c604096)4> :mnesia.start
:ok
#
iex(b@f2209c604096)5> Node.list
[:a@9fa43a09fbea]
#
iex(b@f2209c604096)6> :mnesia.transaction(fn -> :mnesia.read({Employee, 104732}) end)
{:atomic, [{Employee, 104732, "klacke", 7, :male, 98108, {221, 15}}]}
Node B
B Mnesia
•

35. Node A

36. iex(a@9fa43a09fbea)10>
BREAK: (a)bort (c)ontinue (p)roc info (i)nfo (l)oaded
(v)ersion (k)ill (D)b-tables (d)istribution
^Croot@9fa43a09fbea:/var/workspace/mnesia/data/snameA#
Node A
Node
•
iex(b@f2209c604096)6> :mnesia.transaction(fn -> :mnesia.read({Employee, 104732}) end)
{:atomic, [{Employee, 104732, "klacke", 7, :male, 98108, {221, 15}}]}
iex(b@f2209c604096)7>
nil
iex(b@f2209c604096)8> :mnesia.transaction(fn -> :mnesia.read({Employee, 104732}) end)
{:aborted, {:no_exists, Employee}}
Node B

37. 🤔

38. iex(a@9fa43a09fbea)9> :mnesia.create_table(Dept, [attributes: [:id, :name]])
{:atomic, :ok}
iex(a@9fa43a09fbea)10> :mnesia.create_table(Project, [attributes: [:id, :name]])
{:atomic, :ok}
iex(a@9fa43a09fbea)13> :mnesia.create_table(Manager, [type: :bag, attributes:
[:emp, :dept]])
{:atomic, :ok}
iex(a@9fa43a09fbea)14> :mnesia.create_table(AtDep, [attributes: [:emp, :dept_id]])
{:atomic, :ok}
iex(a@9fa43a09fbea)15> :mnesia.create_table(InProj, [type: :bag, attributes:
[:emp, :proj_name]])
{:atomic, :ok}
•
• copies

39. iex(a@9fa43a09fbea)9> :mnesia.create_table(Dept, [ram_copies:
[:"b@f2209c604096"],attributes: [:id, :name]])
{:atomic, :ok}
iex(a@9fa43a09fbea)10> :mnesia.create_table(Project, [ram_copies:
[:"b@f2209c604096"],attributes: [:id, :name]])
{:atomic, :ok}
iex(a@9fa43a09fbea)13> :mnesia.create_table(Manager, [ram_copies:
[:"b@f2209c604096"],type: :bag, attributes: [:emp, :dept]])
{:atomic, :ok}
iex(a@9fa43a09fbea)14> :mnesia.create_table(AtDep, [ram_copies:
[:"b@f2209c604096"],attributes: [:emp, :dept_id]])
{:atomic, :ok}
iex(a@9fa43a09fbea)15> :mnesia.create_table(InProj, [ram_copies:
[:"b@f2209c604096"],type: :bag, attributes: [:emp, :proj_name]])
{:atomic, :ok}
• ram_copies Node table
ram_copies: [:"b@f2209c604096"]
•

40. iex(a@9fa43a09fbea)5> Sample.insert_emp(%{emp_no: 104732, name: "klacke", salary: 7,
sex: :male, phone: 98108, room_no: {221, 015}}, "B/SFR", [:erlang, :mnesia, :otp])
{:atomic, :ok}
Node A
Node B
iex(b@f2209c604096)3> :mnesia.transaction(fn -> :mnesia.read({Employee, 104732}) end)
{:atomic, [{Employee, 104732, "klacke", 7, :male, 98108, {221, 15}}]}
Node A
Node B
iex(b@f2209c604096)4> :mnesia.transaction(fn -> :mnesia.read({Employee, 104732}) end)
{:atomic, [{Employee, 104732, "klacke", 7, :male, 98108, {221, 15}}]}
🎉

42. iex(b@f2209c604096)3> Sample.insert_emp(%{emp_no: 104733, name: "hogehoge", salary: 7,
sex: :male, phone: 98109, room_no: {221, 015}}, "B/SFR", [:erlang, :mnesia, :otp])
{:atomic, :ok}
Node B
Node A
iex(a@9fa43a09fbea)6> :mnesia.transaction(fn -> :mnesia.read({Employee, 104733}) end)
{:atomic, [{Employee, 104733, "hogehoge", 7, :male, 98109, {221, 15}}]}
Node B
Node A
iex(a@9fa43a09fbea)7> :mnesia.transaction(fn -> :mnesia.read({Employee, 104733}) end)
{:aborted, {:no_exists, Employee}}
😱

43. ram_copies: [:"b@f2209c604096"]
•

44. ram_copies: [:"b@f2209c604096"]
•
ram_copies: [node(), :”b@f2209c604096”]

45. iex(b@f2209c604096)3> Sample.insert_emp(%{emp_no: 104733, name: "hogehoge", salary: 7,
sex: :male, phone: 98109, room_no: {221, 015}}, "B/SFR", [:erlang, :mnesia, :otp])
{:atomic, :ok}
Node B
Node A
iex(a@9fa43a09fbea)6> :mnesia.transaction(fn -> :mnesia.read({Employee, 104733}) end)
{:atomic, [{Employee, 104733, "hogehoge", 7, :male, 98109, {221, 15}}]}
Node B
Node A
iex(a@9fa43a09fbea)8> :mnesia.transaction(fn -> :mnesia.read({Employee, 104733}) end)
{:atomic, [{Employee, 104733, "hogehoge", 7, :male, 98108, {221, 15}}]}
🎉

47. • Mnesia
Erlang
•
• EPMD Erlang Distribution
Protocol