scala 带有 MySQL 的 Slick 2.0 的“Hello World”示例
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"Hello World" example for Slick 2.0 with MySQL
提问by Kotaro
Is there an example of how to use the Slick 2.0.1 library for Scala to connect to a MySQL database? I could not find up-to-date examples with Googling...
是否有关于如何使用 Slick 2.0.1 库的 Scala 连接到 MySQL 数据库的示例？我找不到谷歌搜索的最新例子......
Recently, I have been thinking about porting the code for the web application that I have been developing with PHP into Scala. I have been looking for a programming language that has (i) a web application framework with a good number of users, (ii) offers compile time error-checking, (iii) nice testing tools, and so on... After reading about some case studies (e.g.,huffpostand cousera) of developing web applications using Scala and Play framework, it started looking appealing to me and I decided to give it a shot.
最近，我一直在考虑将我一直在用 PHP 开发的 Web 应用程序的代码移植到 Scala 中。我一直在寻找一种编程语言，它具有 (i) 一个拥有大量用户的 Web 应用程序框架，(ii) 提供编译时错误检查，(iii) 不错的测试工具，等等......阅读后一些使用 Scala 和 Play 框架开发 Web 应用程序的案例研究（例如，huffpost和cousera），它开始吸引我，我决定试一试。
As all the data from the previous project reside in a MySQL database, I was looking at what Scala offers for my program to connect to MySQL. I came across Slick. I followed the Hello-Slick examplein the Typesafe Activator, which guided me how to use an in-memory database (i.e.,h2) and I liked its syntax and the level of abstraction. Now, I want to use Slick with MySQL. I tried changing the import statements
由于上一个项目中的所有数据都位于 MySQL 数据库中，因此我正在查看 Scala 为我的程序连接到 MySQL 提供的功能。我遇到了 Slick。我遵循了Typesafe Activator 中的Hello-Slick 示例，它指导我如何使用内存数据库（即h2），我喜欢它的语法和抽象级别。现在，我想在 MySQL 中使用 Slick。我尝试更改导入语句
import scala.slick.driver.H2Driver.simple._
import scala.slick.driver.H2Driver.simple._
to
到
import scala.slick.driver.MySQLDriver.simple._
import scala.slick.driver.MySQLDriver.simple._
in both HelloSlick.scalaand Tables.scalain the aforementioned example (please see the full copy of the code below). However, I am getting the following error message when I compile it:
在这两个HelloSlick.scala和Tables.scala在上述例子中（请参阅下面的代码的完整副本）。但是，我在编译时收到以下错误消息：
/Users/kotaro/Documents/Scala/hello-slick/src/test/scala/TablesSuite.scala
value ddl is not a member of scala.slick.lifted.TableQuery[Suppliers]
def createSchema() = (suppliers.ddl ++ coffees.ddl).create
^
/Users/kotaro/Documents/Scala/hello-slick/src/test/scala/TablesSuite.scala
value ddl 不是 scala.slick.lifted.TableQuery[Suppliers] 的成员
def createSchema() = (suppliers.ddl ++ coffees.ddl).create
^
Does anyone know what is causing this? According to this post (slick exception when trying to connect to MySql), I might be missing to add some dependencies though the error message I'm getting is different. If there is a good example that I can follow to get a grasp of how to use Slick with MySQL, that would help a lot too.
有谁知道是什么原因造成的？根据这篇文章（尝试连接到 MySql 时出现的异常），尽管我收到的错误消息不同，但我可能缺少添加一些依赖项。如果有一个很好的例子可以让我掌握如何在 MySQL 中使用 Slick，那也会有很大帮助。
I am using Scala 2.10.3, MySQL in XAMPP 1.7.3 with OS X 10.8 and JRE 1.6.
我在 OS X 10.8 和 JRE 1.6 的 XAMPP 1.7.3 中使用 Scala 2.10.3、MySQL。
Thank you very much for your help in advance!
非常感谢您的帮助！
Following is the full copy of the code.
以下是代码的完整副本。
HelloSlick.scala
你好Slick.scala
import scala.slick.driver.MySQLDriver.simple._
//import scala.slick.driver.H2Driver.simple._
// The main application
object HelloSlick extends App {
// The query interface for the Suppliers table
val suppliers: TableQuery[Suppliers] = TableQuery[Suppliers]
// the query interface for the Coffees table
val coffees: TableQuery[Coffees] = TableQuery[Coffees]
// Create a connection (called a "session") to an in-memory H2 database
Database.forURL("jdbc:mysql://localhost:3306/test", driver="com.mysql.jdbc.Driver", user="root", password="").withSession { implicit session =>
// Create the schema by combining the DDLs for the Suppliers and Coffees tables using the query interfaces
(suppliers.ddl ++ coffees.ddl).create
/* Create / Insert */
// Insert some suppliers
suppliers += (101, "Acme, Inc.", "99 Market Street", "Groundsville", "CA", "95199")
suppliers += (49, "Superior Coffee", "1 Party Place", "Mendocino", "CA", "95460")
suppliers += (150, "The High Ground", "100 Coffee Lane", "Meadows", "CA", "93966")
// Insert some coffees (using JDBC's batch insert feature)
val coffeesInsertResult: Option[Int] = coffees ++= Seq (
("Colombian", 101, 7.99, 0, 0),
("French_Roast", 49, 8.99, 0, 0),
("Espresso", 150, 9.99, 0, 0),
("Colombian_Decaf", 101, 8.99, 0, 0),
("French_Roast_Decaf", 49, 9.99, 0, 0)
)
val allSuppliers: List[(Int, String, String, String, String, String)] = suppliers.list
// Print the number of rows inserted
coffeesInsertResult foreach (numRows => println(s"Inserted $numRows rows into the Coffees table"))
/* Read / Query / Select */
// Print the SQL for the Coffees query
println("Generated SQL for base Coffees query:\n" + coffees.selectStatement)
// Query the Coffees table using a foreach and print each row
coffees foreach { case (name, supID, price, sales, total) =>
println(" " + name + "\t" + supID + "\t" + price + "\t" + sales + "\t" + total)
}
/* Filtering / Where */
// Construct a query where the price of Coffees is > 9.0
val filterQuery: Query[Coffees, (String, Int, Double, Int, Int)] = coffees.filter(_.price > 9.0)
println("Generated SQL for filter query:\n" + filterQuery.selectStatement)
// Execute the query
println(filterQuery.list)
/* Update */
// Construct an update query with the sales column being the one to update
val updateQuery: Query[Column[Int], Int] = coffees.map(_.sales)
// Print the SQL for the Coffees update query
println("Generated SQL for Coffees update:\n" + updateQuery.updateStatement)
// Perform the update
val numUpdatedRows = updateQuery.update(1)
println(s"Updated $numUpdatedRows rows")
/* Delete */
// Construct a delete query that deletes coffees with a price less than 8.0
val deleteQuery: Query[Coffees,(String, Int, Double, Int, Int)] = coffees.filter(_.price < 8.0)
// Print the SQL for the Coffees delete query
println("Generated SQL for Coffees delete:\n" + deleteQuery.deleteStatement)
// Perform the delete
val numDeletedRows = deleteQuery.delete
println(s"Deleted $numDeletedRows rows")
/* Selecting Specific Columns */
// Construct a new coffees query that just selects the name
val justNameQuery: Query[Column[String], String] = coffees.map(_.name)
println("Generated SQL for query returning just the name:\n" + justNameQuery.selectStatement)
// Execute the query
println(justNameQuery.list)
/* Sorting / Order By */
val sortByPriceQuery: Query[Coffees, (String, Int, Double, Int, Int)] = coffees.sortBy(_.price)
println("Generated SQL for query sorted by price:\n" + sortByPriceQuery.selectStatement)
// Execute the query
println(sortByPriceQuery.list)
/* Query Composition */
val composedQuery: Query[Column[String], String] = coffees.sortBy(_.name).take(3).filter(_.price > 9.0).map(_.name)
println("Generated SQL for composed query:\n" + composedQuery.selectStatement)
// Execute the composed query
println(composedQuery.list)
/* Joins */
// Join the tables using the relationship defined in the Coffees table
val joinQuery: Query[(Column[String], Column[String]), (String, String)] = for {
c <- coffees if c.price > 9.0
s <- c.supplier
} yield (c.name, s.name)
println("Generated SQL for the join query:\n" + joinQuery.selectStatement)
// Print the rows which contain the coffee name and the supplier name
println(joinQuery.list)
/* Computed Values */
// Create a new computed column that calculates the max price
val maxPriceColumn: Column[Option[Double]] = coffees.map(_.price).max
println("Generated SQL for max price column:\n" + maxPriceColumn.selectStatement)
// Execute the computed value query
println(maxPriceColumn.run)
/* Manual SQL / String Interpolation */
// Required import for the sql interpolator
import scala.slick.jdbc.StaticQuery.interpolation
// A value to insert into the statement
val state = "CA"
// Construct a SQL statement manually with an interpolated value
val plainQuery = sql"select SUP_NAME from SUPPLIERS where STATE = $state".as[String]
println("Generated SQL for plain query:\n" + plainQuery.getStatement)
// Execute the query
println(plainQuery.list)
}
}
Tables.scala
表.scala
import scala.slick.driver.MySQLDriver.simple._
import scala.slick.lifted.{ProvenShape, ForeignKeyQuery}
// A Suppliers table with 6 columns: id, name, street, city, state, zip
class Suppliers(tag: Tag) extends Table[(Int, String, String, String, String, String)](tag, "SUPPLIERS") {
def id: Column[Int] = column[Int]("SUP_ID", O.PrimaryKey) // This is the primary key column
def name: Column[String] = column[String]("SUP_NAME")
def street: Column[String] = column[String]("STREET")
def city: Column[String] = column[String]("CITY")
def state: Column[String] = column[String]("STATE")
def zip: Column[String] = column[String]("ZIP")
// Every table needs a * projection with the same type as the table's type parameter
def * : ProvenShape[(Int, String, String, String, String, String)] = (id, name, street, city, state, zip)
}
// A Coffees table with 5 columns: name, supplier id, price, sales, total
class Coffees(tag: Tag) extends Table[(String, Int, Double, Int, Int)](tag, "COFFEES") {
def name: Column[String] = column[String]("COF_NAME", O.PrimaryKey)
def supID: Column[Int] = column[Int]("SUP_ID")
def price: Column[Double] = column[Double]("PRICE")
def sales: Column[Int] = column[Int]("SALES")
def total: Column[Int] = column[Int]("TOTAL")
def * : ProvenShape[(String, Int, Double, Int, Int)] = (name, supID, price, sales, total)
// A reified foreign key relation that can be navigated to create a join
def supplier: ForeignKeyQuery[Suppliers, (Int, String, String, String, String, String)] =
foreignKey("SUP_FK", supID, TableQuery[Suppliers])(_.id)
}
采纳答案by cvogt
You probably overlooked that the error message refers to `TableSuite.scala``
您可能忽略了错误消息指的是“TableSuite.scala”
/Users/kotaro/Documents/Scala/hello-slick/src/test/scala/TablesSuite.scala
value ddl is not a member of scala.slick.lifted.TableQuery[Suppliers]
def createSchema() = (suppliers.ddl ++ coffees.ddl).create
You need to change the import in there as well.
您还需要更改那里的导入。
