At Lisp Meetup #43

1. MITO,
A SUCCESSOR OF INTEGRAL
LISP MEETUP #43 Aug 30, 2016

2. I’m Eitaro Fukamachi
@nitro_idiot fukamachi

3. Do you use
RDBMS?

4. Do you know
O/R Mapper?

5. RDBMS
Record
Record
Record
Table
Table
Table

6. RDBMS
Record
Record
Record
Table
Table
Table
CLOS class
CLOS class
CLOS class

7. RDBMS
Record
Record
Record
Table
Table
Table
CLOS class
CLOS class
CLOS class
make-instance

8. RDBMS
Record
Record
Record
Table
Table
Table
CLOS class
CLOS class
CLOS class
CLOS
Object
CLOS
Object
CLOS
Object
make-instance

9. CLOS class
CLOS class
CLOS class
CLOS
Object
CLOS
Object
CLOS
Object
make-instance

10. CLOS class
CLOS class
CLOS class
CLOS
Object
CLOS
Object
CLOS
Object
make-instance
▸ Abstracts RDBMS including SQL
▸ Maps RDB tables to CLOS classes
▸ Maps RDB records to CLOS objects
▸ Can add methods
▸ Accelerates development

11. Do you know O/R Mapper?
ORM Examples
▸ CLSQL
▸ Postmodern

12. Do you know O/R Mapper?
ORM Examples
▸ CLSQL
▸ Postmodern
▸ Integral

13. Do you know O/R Mapper?
ORM Examples
▸ CLSQL
▸ Postmodern
▸ Integral
A talk about “Integral”
2 years ago

14. Do you know O/R Mapper?
ORM Examples
▸ CLSQL
▸ Postmodern
▸ Integral
▸ Crane
A talk about “Integral”
2 years ago

15. Do you know O/R Mapper?
ORM Examples
▸ CLSQL
▸ Postmodern
▸ Integral (Not recommended)
▸ Crane
▸ Mito
A talk about “Integral”
2 years ago
NEW!

16. What’s new
in Mito?

17. What’s new in Mito?
Mito, a successor of Integral
▸ Supports PostgreSQL, as well as MySQL & SQLite3
▸ Implicit columns (auto-pk & record-timestamps)
▸ Reference between DB table classes
▸ Eager loading
▸ Inheritance of DB table classes
▸ Migrations
▸ Schema versioning

18. Implicit columns,
auto-pk &
record-timestamps

19. (defclass user ()
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))

20. CREATE TABLE user (
id BIGSERIAL NOT NULL PRIMARY KEY,
name VARCHAR(64) NOT NULL,
email VARCHAR(128),
created_at TIME,
updated_at TIME
)
(defclass user ()
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))

21. CREATE TABLE user (
id BIGSERIAL NOT NULL PRIMARY KEY,
name VARCHAR(64) NOT NULL,
email VARCHAR(128),
created_at TIME,
updated_at TIME
)
(defclass user ()
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))

22. CREATE TABLE user (
id BIGSERIAL NOT NULL PRIMARY KEY,
name VARCHAR(64) NOT NULL,
email VARCHAR(128),
created_at TIME,
updated_at TIME
)
(defclass user ()
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))

23. CREATE TABLE user (
id BIGSERIAL NOT NULL PRIMARY KEY,
name VARCHAR(64) NOT NULL,
email VARCHAR(128),
created_at TIME,
updated_at TIME
)
(defclass user ()
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))

24. CREATE TABLE user (
id BIGSERIAL NOT NULL PRIMARY KEY,
name VARCHAR(64) NOT NULL,
email VARCHAR(128),
created_at TIME,
updated_at TIME
)
(defclass user ()
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))
auto-pk
record-timestamps

25. Reference
between DB table classes

26. Reference between DB table classes
(defclass user () …
(:metaclass mito:dao-table-class))

27. (defclass tweet ()
((status :col-type :text
:initarg :status
:accessor tweet-status)
(user-id :col-type (:bigint () :unsigned)
:initarg :user-id
:accessor tweet-user-id))
(:metaclass mito:dao-table-class))
Reference between DB table classes
(defclass user () …
(:metaclass mito:dao-table-class))

28. (defclass tweet ()
((status :col-type :text
:initarg :status
:accessor tweet-status)
(user-id :col-type (:bigint () :unsigned)
:initarg :user-id
:accessor tweet-user-id))
(:metaclass mito:dao-table-class))
Reference between DB table classes
(defclass user () …
(:metaclass mito:dao-table-class))
(defun tweet-user (tweet)
(mito:find-dao ‘user
:id (tweet-user-id tweet)))

29. (defclass tweet ()
((status :col-type :text
:initarg :status
:accessor tweet-status)
(user-id :col-type (:bigint () :unsigned)
:initarg :user-id
:accessor tweet-user-id))
(:metaclass mito:dao-table-class))
Reference between DB table classes
(defclass user () …
(:metaclass mito:dao-table-class))
(defun tweet-user (tweet)
(mito:find-dao ‘user
:id (tweet-user-id tweet)))
These kind of accessors are quite common.

30. Reference between DB table classes
(defclass user () …
(:metaclass mito:dao-table-class))
(defclass tweet ()
((status :col-type :text
:initarg :status
:accessor tweet-status)
(user :col-type user
:initarg :user
:accessor tweet-user))
(:metaclass mito:dao-table-class))

31. It may cause a
performance issue:
N+1 query.

32. Eager loading
helps.

33. Reference between DB table classes
(defclass user () …
(:metaclass mito:dao-table-class))
(defclass tweet ()
((status :col-type :text
:initarg :status
:accessor tweet-status)
(user :col-type user
:initarg :user
:accessor tweet-user))
(:metaclass mito:dao-table-class))
;; Tweets contain “Japan”
(select-dao 'tweet
(where (:like :status “%Japan%")))
;; Getting names of tweeted users.
(mapcar (lambda (tweet)
(user-name (tweet-user tweet)))
*)
BAD EXAMPLE

34. Reference between DB table classes
(defclass user () …
(:metaclass mito:dao-table-class))
(defclass tweet ()
((status :col-type :text
:initarg :status
:accessor tweet-status)
(user :col-type user
:initarg :user
:accessor tweet-user))
(:metaclass mito:dao-table-class))
;; Tweets contain “Japan”
(select-dao 'tweet
(where (:like :status “%Japan%")))
;; Getting names of tweeted users.
(mapcar (lambda (tweet)
(user-name (tweet-user tweet)))
*)
SQL execution for each records.
(N times)
BAD EXAMPLE

35. Reference between DB table classes
(defclass user () …
(:metaclass mito:dao-table-class))
(defclass tweet ()
((status :col-type :text
:initarg :status
:accessor tweet-status)
(user :col-type user
:initarg :user
:accessor tweet-user))
(:metaclass mito:dao-table-class))
;; Tweets contain “Japan”
(select-dao 'tweet
(includes 'user)
(where (:like :status “%Japan%")))
;; No additional SQLs will be executed.
(tweet-user (first *))
GOOD EXAMPLE

36. Reference between DB table classes
(defclass user () …
(:metaclass mito:dao-table-class))
(defclass tweet ()
((status :col-type :text
:initarg :status
:accessor tweet-status)
(user :col-type user
:initarg :user
:accessor tweet-user))
(:metaclass mito:dao-table-class))
;; Tweets contain “Japan”
(select-dao 'tweet
(includes 'user)
(where (:like :status “%Japan%")))
;; No additional SQLs will be executed.
(tweet-user (first *))
Throw 1 query to retrieve users
beforehand.
GOOD EXAMPLE

37. Inheritance of
DB table classes

38. Sometimes
similar DB tables are needed.
Photo by Andrey Shipilov

39. Inheritance of DB table classes
Ex) SQL Antipatterns: Logical Deletion
slideshare.net/t_wada/ronsakucasual
slideshare.net/SoudaiSone/postgre-sql-54919575
PostgreSQL Antipatterns

40. Inheritance of DB table classes
Ex) SQL Antipatterns: Logical Deletion
(defclass user ()
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))
(defclass deleted-user (user)
((deleted-at :col-type :datetime
:initarg :deleted-at
:initform (local-time:now)
:accessor user-deleted-at))
(:metaclass mito:dao-table-class))

41. Inheritance of DB table classes
Ex) SQL Antipatterns: Logical Deletion
(defclass user ()
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))
(defclass deleted-user (user)
((deleted-at :col-type :datetime
:initarg :deleted-at
:initform (local-time:now)
:accessor user-deleted-at))
(:metaclass mito:dao-table-class))
CREATE TABLE deleted_user (
id BIGSERIAL NOT NULL PRIMARY KEY,
name VARCHAR(64) NOT NULL,
email VARCHAR(128),
deleted_at TIME NOT NULL,
created_at TIME,
updated_at TIME
)

42. Inheritance of DB table classes
Ex) SQL Antipatterns: Logical Deletion
(defclass user ()
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))
(defclass deleted-user (user)
((deleted-at :col-type :datetime
:initarg :deleted-at
:initform (local-time:now)
:accessor user-deleted-at))
(:metaclass mito:dao-table-class))
CREATE TABLE deleted_user (
id BIGSERIAL NOT NULL PRIMARY KEY,
name VARCHAR(64) NOT NULL,
email VARCHAR(128),
deleted_at TIME NOT NULL,
created_at TIME,
updated_at TIME
)

43. Inheritance of DB table classes
Ex) SQL Antipatterns: Logical Deletion
(defmethod mito:delete-dao :before ((user user))
(mito:create-dao ‘deleted-user
:id (object-id user)
:name (user-name user)
:email (user-email user)
:created-at (object-created-at user)
:updated-at (object-updated-at user)))
Copy “user” records to “deleted_user” before deleting.

44. Mixin
DB table injection
Photo by Steve Snodgrass

45. Inheritance of DB table classes - Mixin
Mixin
▸ Injects columns and methods
▸ record-timestamps is an actual example
▸ Adds created_at & updated_at

46. Inheritance of DB table classes - Mixin
Ex) mito-auth
▸ Managing user passwords is dull
▸ Stores hashed passwords
▸ Authenticates
github.com/fukamachi/mito-auth

47. Inheritance of DB table classes - Mixin
Ex) mito-auth
(defclass user (has-secure-password)
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))
github.com/fukamachi/mito-auth

48. Inheritance of DB table classes - Mixin
Ex) mito-auth
(defclass user (has-secure-password)
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))
(mito:create-dao ‘user
:name “fukamachi”
:email “e.arrows@gmail.com”
:password “c0mmon-l1sp”)
github.com/fukamachi/mito-auth

49. Inheritance of DB table classes - Mixin
Ex) mito-auth
(defclass user (has-secure-password)
((name :col-type (:varchar 64)
:initarg :name
:accessor user-name)
(email :col-type (or (:varchar 128) :null)
:initarg :email
:accessor user-email))
(:metaclass mito:dao-table-class))
(mito:create-dao ‘user
:name “fukamachi”
:email “e.arrows@gmail.com”
:password “c0mmon-l1sp”)
Stores a hashed password and salt, not a plain text.
github.com/fukamachi/mito-auth

50. What wasn’t mentioned
▸ Migrations
▸ Schema versioning
▸ Inflation/deflation
▸ See https://github.com/fukamachi/mito

51. Thanks.

52. EITARO FUKAMACHI
8arrow.org
@nitro_idiot fukamachi

53. Thanks.
See Also
▸ https://github.com/fukamachi/mito
▸ https://github.com/fukamachi/mito-auth
▸ https://github.com/fukamachi/mito-attachment