【发布时间】：2018-02-19 11:04:50
【问题描述】：
我想在 ScalikeJDBC 中拥有带有平面数据库表的嵌套对象。
Meta(id: String)
Poll(meta: Option[Meta], value: String)
映射到表
Poll(id VARCHAR(100), value VARCHAR(100))
我不确定如何执行此操作，尤其是使用 SQLSyntaxSupport。
【问题讨论】：
标签： scala scalikejdbc
【发布时间】：2018-02-19 11:04:50
【问题描述】：
试试下面的代码。
另请参阅： - http://scalikejdbc.org/documentation/operations.html - http://scalikejdbc.org/documentation/sql-interpolation.html
build.sbt
scalaVersion := "2.12.4"
libraryDependencies ++= Seq(
"org.scalikejdbc" %% "scalikejdbc" % "3.2.1",
"org.scalikejdbc" %% "scalikejdbc-syntax-support-macro" % "3.2.1",
"com.h2database" % "h2" % "1.4.196",
"ch.qos.logback" % "logback-classic" % "1.2.3"
)
sample.scala
import scalikejdbc._
Class.forName("org.h2.Driver")
ConnectionPool.singleton("jdbc:h2:mem:hello", "user", "pass")
case class Meta(id: String)
case class Poll(meta: Option[Meta] = None, value: String)
implicit val metaBinders = Binders.of[Meta]
// For TypeBinder (f: Any => A)
{
case null => null
case str: String => Meta(str)
case v: Any => Meta(v.toString)
}
// For ParameterBinderFactory (A => (PreparedStatement, Int) => Unit)
{ v =>
(ps, idx) =>
ps.setString(idx, v.id)
}
object Poll extends SQLSyntaxSupport[Poll] {
override val nameConverters = Map("^meta$" -> "id")
def apply(rs: WrappedResultSet, rn: ResultName[Poll]) = autoConstruct(rs, rn)
}
implicit val session = AutoSession
sql"""
create table poll (
id varchar(64),
value varchar(64) not null
)
""".execute.apply()
sql"insert into poll (id, value) values ('meta-id-1', 'value-1')".update.apply()
sql"insert into poll (id, value) values (null, 'value-2')".update.apply()
val p = Poll.syntax("p")
val polls = withSQL {
select.from(Poll as p)
}.map(rs => Poll(rs, p.resultName)).list.apply()
println(polls)
标准输出
22:10:49.828 [run-main-0] DEBUG scalikejdbc.ConnectionPool$ - Registered connection pool : ConnectionPool(url:jdbc:h2:mem:hello, user:user) using factory : <default>
22:10:49.832 [run-main-0] DEBUG scalikejdbc.ConnectionPool$ - Registered singleton connection pool : ConnectionPool(url:jdbc:h2:mem:hello, user:user)
22:10:50.123 [run-main-0] DEBUG scalikejdbc.StatementExecutor$$anon$1 - SQL execution completed
[SQL Execution]
create table poll ( id varchar(64), value varchar(64) not null ); (1 ms)
[Stack Trace]
...
Foo$.delayedEndpoint$Foo$1(foo.scala:34)
Foo$delayedInit$body.apply(foo.scala:2)
scala.Function0.apply$mcV$sp(Function0.scala:34)
scala.Function0.apply$mcV$sp$(Function0.scala:34)
scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
scala.App.$anonfun$main$1$adapted(App.scala:76)
scala.collection.immutable.List.foreach(List.scala:389)
scala.App.main(App.scala:76)
scala.App.main$(App.scala:74)
Foo$.main(foo.scala:2)
$line3.$read$$iw$$iw$.<init>(<console>:12)
$line3.$read$$iw$$iw$.<clinit>(<console>)
$line3.$eval$.$print$lzycompute(<console>:7)
$line3.$eval$.$print(<console>:6)
$line3.$eval.$print(<console>)
...
22:10:50.130 [run-main-0] DEBUG scalikejdbc.StatementExecutor$$anon$1 - SQL execution completed
[SQL Execution]
insert into poll (id, value) values ('meta-id-1', 'value-1'); (0 ms)
[Stack Trace]
...
Foo$.delayedEndpoint$Foo$1(foo.scala:36)
Foo$delayedInit$body.apply(foo.scala:2)
scala.Function0.apply$mcV$sp(Function0.scala:34)
scala.Function0.apply$mcV$sp$(Function0.scala:34)
scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
scala.App.$anonfun$main$1$adapted(App.scala:76)
scala.collection.immutable.List.foreach(List.scala:389)
scala.App.main(App.scala:76)
scala.App.main$(App.scala:74)
Foo$.main(foo.scala:2)
$line3.$read$$iw$$iw$.<init>(<console>:12)
$line3.$read$$iw$$iw$.<clinit>(<console>)
$line3.$eval$.$print$lzycompute(<console>:7)
$line3.$eval$.$print(<console>:6)
$line3.$eval.$print(<console>)
...
22:10:50.131 [run-main-0] DEBUG scalikejdbc.StatementExecutor$$anon$1 - SQL execution completed
[SQL Execution]
insert into poll (id, value) values (null, 'value-2'); (0 ms)
[Stack Trace]
...
Foo$.delayedEndpoint$Foo$1(foo.scala:37)
Foo$delayedInit$body.apply(foo.scala:2)
scala.Function0.apply$mcV$sp(Function0.scala:34)
scala.Function0.apply$mcV$sp$(Function0.scala:34)
scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
scala.App.$anonfun$main$1$adapted(App.scala:76)
scala.collection.immutable.List.foreach(List.scala:389)
scala.App.main(App.scala:76)
scala.App.main$(App.scala:74)
Foo$.main(foo.scala:2)
$line3.$read$$iw$$iw$.<init>(<console>:12)
$line3.$read$$iw$$iw$.<clinit>(<console>)
$line3.$eval$.$print$lzycompute(<console>:7)
$line3.$eval$.$print(<console>:6)
$line3.$eval.$print(<console>)
...
22:10:50.227 [run-main-0] DEBUG scalikejdbc.StatementExecutor$$anon$1 - SQL execution completed
[SQL Execution]
select p.id as i_on_p, p.value as v_on_p from poll p; (0 ms)
[Stack Trace]
...
Foo$.delayedEndpoint$Foo$1(foo.scala:42)
Foo$delayedInit$body.apply(foo.scala:2)
scala.Function0.apply$mcV$sp(Function0.scala:34)
scala.Function0.apply$mcV$sp$(Function0.scala:34)
scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
scala.App.$anonfun$main$1$adapted(App.scala:76)
scala.collection.immutable.List.foreach(List.scala:389)
scala.App.main(App.scala:76)
scala.App.main$(App.scala:74)
Foo$.main(foo.scala:2)
$line3.$read$$iw$$iw$.<init>(<console>:12)
$line3.$read$$iw$$iw$.<clinit>(<console>)
$line3.$eval$.$print$lzycompute(<console>:7)
$line3.$eval$.$print(<console>:6)
$line3.$eval.$print(<console>)
...
List(Poll(Some(Meta(meta-id-1)),value-1), Poll(None,value-2))
【讨论】：
-
非常感谢@kazuhiro-sera，这可以在 Meta 中使用两个值吗？创建日期？大多数情况下，我猜除了 Map("^meta$" -> "id") ？
关于附加问题，您可以手动绑定多个值，如下所示：
object Poll extends SQLSyntaxSupport[Poll] {
override val columns = Seq("id" "creation_time", "value")
def apply(rs: WrappedResultSet, rn: ResultName[Poll]) = {
new Poll(
meta = new Meta(
id = rs.get[Long](rn.id),
creationTime = rs.get[ZonedDateTime](rn.creationTime)
),
value = rs.get[String](rn.value)
)
}
}
【讨论】：