我用的是play 2.4和Slick 3，是否可以自动生成ddl脚本，是进化的？
在官方文档中我找到了一些脚本，但我应该将它放在游戏框架中的哪个位置？ http://slick.typesafe.com/doc/3.1.0/schemas.html
您是否知道任何库来管理代码演变而不是编写普通 SQL？
【问题讨论】：
标签： scala playframework slick playframework-evolutions
我使用 PostgresDriver 做了一些解决方法，我创建了模块，将 DDL 打印到文件。每次代码更改后，我只需要替换 1.sql 或稍后修改下一个进化脚本：
ComputersDatabaseModule.scala
package bootstrap
import com.google.inject.AbstractModule
import play.api.{Mode, Play}
class ComputersDatabaseModule extends AbstractModule {
protected def configure() = {
bind(classOf[CreateDDL]).asEagerSingleton()
bind(classOf[InitialData]).asEagerSingleton()
}
}
CreateDDL.scala
package bootstrap
import java.io.PrintWriter
import javax.inject.Inject
import dao.{CompaniesMapping, ComputersMapping}
import play.api.db.slick.{HasDatabaseConfigProvider, DatabaseConfigProvider}
import slick.driver.JdbcProfile
/**
* Creates DDL script
*/
private[bootstrap] class CreateDDL @Inject()(protected val dbConfigProvider: DatabaseConfigProvider) extends HasDatabaseConfigProvider[JdbcProfile] with
ComputersMapping with CompaniesMapping {
def createDDLScript() = {
import slick.driver.PostgresDriver.api._
val allSchemas = companies.schema ++ computers.schema
val writer = new PrintWriter("target/migration_ddl.sql")
writer.write("# --- !Ups\n\n")
allSchemas.createStatements.foreach { s => writer.write(s + ";\n") }
writer.write("\n\n# --- !Downs\n\n")
allSchemas.dropStatements.foreach { s => writer.write(s + ";\n") }
writer.close()
}
createDDLScript()
}
ComputersDAO.scala
package dao
import java.util.Date
import javax.inject.{Inject, Singleton}
import models.{Company, Computer, Page}
import play.api.db.slick.{DatabaseConfigProvider, HasDatabaseConfigProvider}
import play.api.libs.concurrent.Execution.Implicits.defaultContext
import slick.driver.JdbcProfile
import scala.concurrent.Future
trait ComputersMapping { self: HasDatabaseConfigProvider[JdbcProfile] =>
import driver.api._
class Computers(tag: Tag) extends Table[Computer](tag, "COMPUTER") {
implicit val dateColumnType = MappedColumnType.base[Date, Long](d => d.getTime, d => new Date(d))
def id = column[Long]("ID", O.PrimaryKey, O.AutoInc)
def name = column[String]("NAME")
def introduced = column[Option[Date]]("INTRODUCED")
def discontinued = column[Option[Date]]("DISCONTINUED")
def companyId = column[Option[Long]]("COMPANY_ID")
def * = (id.?, name, introduced, discontinued, companyId) <> (Computer.tupled, Computer.unapply)
}
val computers = TableQuery[Computers]
}
@Singleton()
class ComputersDAO @Inject() (protected val dbConfigProvider: DatabaseConfigProvider) extends CompaniesMapping with ComputersMapping
with HasDatabaseConfigProvider[JdbcProfile] {
import driver.api._
/** Retrieve a computer from the id. */
def findById(id: Long): Future[Option[Computer]] =
db.run(computers.filter(_.id === id).result.headOption)
/** Count all computers. */
def count(): Future[Int] = {
// this should be changed to
// db.run(computers.length.result)
// when https://github.com/slick/slick/issues/1237 is fixed
db.run(computers.map(_.id).length.result)
}
/** Count computers with a filter. */
def count(filter: String): Future[Int] = {
db.run(computers.filter { computer => computer.name.toLowerCase like filter.toLowerCase }.length.result)
}
/** Return a page of (Computer,Company) */
def list(page: Int = 0, pageSize: Int = 10, orderBy: Int = 1, filter: String = "%"): Future[Page[(Computer, Company)]] = {
val offset = pageSize * page
val query =
(for {
(computer, company) <- computers joinLeft companies on (_.companyId === _.id)
if computer.name.toLowerCase like filter.toLowerCase
} yield (computer, company.map(_.id), company.map(_.name)))
.drop(offset)
.take(pageSize)
for {
totalRows <- count(filter)
list = query.result.map { rows => rows.collect { case (computer, id, Some(name)) => (computer, Company(id, name)) } }
result <- db.run(list)
} yield Page(result, page, offset, totalRows)
}
/** Insert a new computer. */
def insert(computer: Computer): Future[Unit] =
db.run(computers += computer).map(_ => ())
/** Insert new computers. */
def insert(computers: Seq[Computer]): Future[Unit] =
db.run(this.computers ++= computers).map(_ => ())
/** Update a computer. */
def update(id: Long, computer: Computer): Future[Unit] = {
val computerToUpdate: Computer = computer.copy(Some(id))
db.run(computers.filter(_.id === id).update(computerToUpdate)).map(_ => ())
}
/** Delete a computer. */
def delete(id: Long): Future[Unit] =
db.run(computers.filter(_.id === id).delete).map(_ => ())
}
添加配置（application.config）：
play.modules.enabled += "bootstrap.ComputersDatabaseModule"
【讨论】：
在 Play 2.4 和更新版本中，slick 插件不再创造进化。为此，我在开发模式中添加了一个页面，该页面始终显示浏览器中所有演变的最新版本。这种方法与模块系统中所有即将发生的变化兼容，因为它不使用任何模块。使用依赖注入，它完全使用您在 application.conf 文件中配置的 Slick 数据库驱动程序
我在 config/routes 中添加了以下行：
GET /evolutions.sql controllers.SchemaEvolutionsController.evolutions
然后我创建了一个控制器（app/controllers/SchemaEvolutionsController.scala）
package controllers
import com.google.inject.Inject
import dao.CatDao
import models.HasSchemaDescription
import models.HasSchemaDescription.SqlSchemaDescription
import play.api.Environment
import play.api.mvc.{Action, Controller}
import play.api.Mode
class SchemaEvolutionsController @Inject() (environment: Environment, catDao : CatDao) extends Controller {
def allSchemas : Seq[HasSchemaDescription] = List(catDao) // List all schemas here
def descriptionsForAllSchemas : Seq[SqlSchemaDescription] = allSchemas.map(_.schemaDescription)
def evolutions = Action {
environment.mode match {
case Mode.Prod => NotFound
case _ => Ok(views.txt.evolutions(descriptionsForAllSchemas)).withHeaders(CONTENT_TYPE -> "text/plain")
}
}
}
对于这个控制器当然有对应的视图（views/evolutions.scala.txt）
@import models.HasSchemaDescription.SqlSchemaDescription
@(schemaDescriptions : Seq[SqlSchemaDescription])
# Get the newest version of this evolutions script on the address
# http://localhost:9000@(controllers.routes.SchemaEvolutionsController.evolutions)
# when the server runs in development mode
# --- !Ups
@for(
schemaDescription <- schemaDescriptions;
statement <- schemaDescription.createStatements) {
@(statement.replaceAll(";",";;"));
}
# --- !Downs
@for(
schemaDescription <- schemaDescriptions;
statement <- schemaDescription.dropStatements) {
@(statement.replaceAll(";",";;"));
}
对于 DAO 对象，我添加了一个通用特征来获取架构描述 (app/models/HasSchemaDescription)：
package models
import models.HasSchemaDescription.SqlSchemaDescription
trait HasSchemaDescription {
def schemaDescription: SqlSchemaDescription
}
object HasSchemaDescription {
type SqlSchemaDescription = slick.profile.SqlProfile#SchemaDescription
}
现在对于每个 DAO 对象，我必须实现 trait 并将 DAO 添加到 SchemaEvolutionsController。
例如用于服务 cat 对象的 DAO：
class CatDao @Inject()(protected val dbConfigProvider: DatabaseConfigProvider)
extends HasDatabaseConfigProvider[JdbcProfile] with HasSchemaDescription {
import driver.api._
private val Cats = TableQuery[CatsTable]
def schemaDescription : SqlSchemaDescription = Cats.schema
def findById(id : Int) : Future[Option[Cat]] = db.run(Cats.filter(_.id === id).result.headOption)
private class CatsTable(tag: Tag) extends Table[Cat](tag, "CAT") {
def id = column[Int]("ID", O.PrimaryKey, O.AutoInc)
def name = column[String]("NAME")
def color = column[String]("COLOR")
def age = column[Option[Int]]("AGE")
def * = (id, name, color, age) <> (Cat.tupled, Cat.unapply _)
}
}
通过此示例，您在http://localhost:9000/evolutions.sql 上得到以下结果
# Get the newest version of this evolutions script on the address
# http://localhost:9000/evolutions.sql
# when the server runs in development mode
# --- !Ups
create table `CAT` (`ID` INTEGER NOT NULL AUTO_INCREMENT PRIMARY KEY,`NAME` TEXT NOT NULL,`COLOR` TEXT NOT NULL,`AGE` INTEGER);
# --- !Downs
drop table `CAT`;
【讨论】：