Юрий Буянов «Squeryl — ORM с человеческим лицом»

SQUERYL
ORM ! "#$%&#"#!'() $(*%)

!"#$ %&'()* e-Legion Ltd., 2011
1

ORM

Query q = entityManager.createQuery(
"SELECT AVG(g.scoreInPercentage) FROM Grades g where g.subjectId = :subjectId"
);

q.setParameter(1, mathId);

Number avg = (Number) q.getSingleResult();

avg.floatValue();

2

ORM

Query q = entityManager.createQuery(
"SELECT AVG(g.scoreInPercentage) FROM Grades g where g.subjectId = :subjectId"
);

q.setParameter(1, mathId);

Number avg = (Number) q.getSingleResult();

avg.floatValue();

3

TYPE SAFE ORM (JPA 2)

EntityManager em = ...
CriteriaBuilder qb = em.getCriteriaBuilder();

CriteriaQuery<Person> c = qb.createQuery(Person.class);
Root<Person> p = c.from(Person.class);
Predicate condition = qb.gt(p.get(Person_.age), 20);
c.where(condition);
TypedQuery<Person> q = em.createQuery(c);
List<Person> olderThan20s = q.getResultList();

4

SQUERYL

ORM

SQL-+%,%-./0 DSL ,$1 23+4%!%&

564%731 6(+(23*(1

8#.9:# '%,3, -%$9:# ,#$3

5

TYPE SAFE ORM (JPA 2)

EntityManager em = ...
CriteriaBuilder qb = em.getCriteriaBuilder();

CriteriaQuery<Person> c = qb.createQuery(Person.class);
Root<Person> p = c.from(Person.class);
Predicate condition = qb.gt(p.get(Person_.age), 20);
c.where(condition);
TypedQuery<Person> q = em.createQuery(c);
List<Person> olderThan20s = q.getResultList();

6

SQUERYL

val olderThan20s = people.where(_.age gt 20)

7

SQUERYL

val olderThan20s =

from (people) ( p =>
select (p)
where (p.age gt 20)
)

8

!"#!$%

;.(*(3$(23*(1
<43.23'*((
5=#)3
Insert
Select

Update
Delete

10

&#&'&()&*('&+
import org.squeryl.SessionFactory
import java.sql.DriverManager._

Class.forName("org.h2.Driver")

SessionFactory.concreteFactory = Some { ()=>
Session.create(
getConnection("jdbc:h2:mem:"),
new H2Adapter
)
}

“>3(&.31” ?3-4('3

;!+%$92@06# ConnectionPool (DBCP, BoneCP)

11

,-(#*(.'&&

transaction { ... }

&!#7,3 .3"(.3#6 .%&@A 643.23'*(A ( '%))(6(6
& '%.*#

inTransaction { ... }

.("#7% .# ,#$3#6, #!$( (!+%$92@#6!1 &.@64(
,4@7%0 643.23'*((

12

"/01(
(PrimitiveTypeMode)

case class User(
id: Long = 0,
@Column(length = 256)
email: String,
name: String,
rating: Int = 0,
) extends KeyedEntity[Long]

Plain Old Scala Object ()%B.% case)
563.,346./# 6(+/ ,$1 +%$#0
C%$1 )%7@6 -/69 var ($( val
8%B.% @'32369 432)#4, ()1 !6%$-*3 & -32#
>3!$#,%&369 KeyedEntity .# %-1236#$9.%

13

"/01(
(CustomTypeMode)

5$%B./# '$3!!/ ,$1 +%$#0
8%7@6 &'$A"369 & !#-1 &3$(,3*(A, etc

14

"/01(

object MySchema extends Schema {
val users = table[User]

on(users) { u => declare(
u.id is (autoIncremented),
u.email is (unique)
)
}
}

transaction { MySchema.create }

<3-$(*/
D743.("#.(1
5&12(

15

INSERT

import MySchema._

val vasya =
users.insert(new User("vasya@example.com", "Vasya"))

users.insert(List(user1, user2))

16

SELECT
from(users) ( u =>
select(u)
where(u.name like “%Vasya%”)
)

from(users) ( u =>
select(u.id, u.email)
orderBy(u.id asc)
)

users.where( _.rating.~ >= 0)

//Option[User]
users.lookup(1)

17

FULL UPDATE

//используем copy
//поскольку все поля immutable

val updatedVasya =
vasya.copy(rating = vasya.rating + 1)

users.update(updatedVasya)

18

PARTIAL UPDATE

val updated =
update(users) ( u =>
set(u.rating := u.rating.~ + 1)
where(u.name like "%Vasya%")
)

println("%s Vasyas rated" format updated)

~. "6%-/ .# +@6369 Int.+ ( SQL ‘+’

&)#!6% ~. )%B.% (!+%$92%&369 u.rating plus 1

19

DELETE

users.delete(1)

val deleted =
users.deleteWhere( u =>
u.rating.~ < 0
)

println("%s users deleted" format deleted)

20

2$&3(01"+ 2()450

21

2$&3(01"+ 2()450

5%!63&./# 23+4%!/
Group By ( 374#73*(1
Joins
Relations

22

COMPOSITE SELECT

val rated =

val vasyasRated =
from(rated) ( u =>
select(u)
where(u.name like “%Vasya%”)
)

23

NESTED SELECT

val rated =

val vasyasRated =
from(rated) ( u =>
select(u)
where(u.id in
from(rated)
(r => select(r.id))
)
)

24

067 SELECT

C%!643.(".31 &/-%4'3
from(users) ( u => ... ).page(offset, pageLength)

Distinct
from(users) ( u => ... ).distinct

ForUpdate
from(users) ( u => ... ).forUpdate

25

(3-03('&+

val ratingDistribution =
from(users) ( u =>
groupBy(u.rating)
compute(count(u.id))
)

ratingDistribution foreach { r=>
println(“%s: %s” format (r.key, r.measures))
}

26

JOIN

from(users, posts) ( (u,p) =>
select(u.name, p)
where(u.id === p.userId)
)

from(users, avatars.leftOuter) ( (u,a) =>
select(u, a.url)
on(u.id === a.map(_.userId))
)

27

RELATIONS

object MySchema extends Schema {
val users = table[User]
val posts = table[Post]
val userPosts =
oneToManyRelation(users, posts) via ( (u,p) =>
u.id === p.userId
)
}

28

(STATELESS) RELATIONS

case class User (....) extends KeyedEntity[Long] {
//OneToMany[Post] < Query
lazy val posts = MySchema.userPosts.left(this)
}

//ManyToOne[User] < Query
lazy val user = MySchema.userPosts.right(this)
}

val user =
users.lookup(1).getOrElse(error(“user not found”))

for (p <- user.posts)
println(p.title)

29

STATEFUL RELATIONS


//StatefulOneToMany[Post] < Iterable[Post]
lazy val posts = MySchema.userPosts.leftStateful(this)

}

case User (....) extends KeyedEntity[Long] {

//StetefulManyToOne[User]
lazy val user = MySchema.userPosts.rightStateful(this)

}

30

#02!",(,.&

Compile-time Voodoo
createEqualityExpressionWithLastAccessedFieldReferenceAndConstant

>#6 UNION
5$(:'%) @)./0 DSL
where ( u.name === stringOpt.? ) //работает

where ( u.flag === boolOpt.? ) //не работает

not(not(u.flag)).inhibitWhen(boolOpt != Some(true))
and
not(u.flag).inhibitWhen(boolOpt != Some(false))

32

"8("&9!

email: yuri.buyanov@e-legion.com

email: yuri.buyanov@gmail.com

www: http://digal.github.com/

twitter: @digal

34

Юрий Буянов «Squeryl — ORM с человеческим лицом»

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