Mysql 具有多个联接的表的光滑普通SQL隐式GetResult
我使用的是光滑的普通SQL,我有一个类似以下内容的表模式:Mysql 具有多个联接的表的光滑普通SQL隐式GetResult,mysql,scala,slick,Mysql,Scala,Slick,我使用的是光滑的普通SQL,我有一个类似以下内容的表模式: CREATE TABLE users ( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, name VARCHAR(191) NOT NULL ); CREATE TABLE images ( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, url VARCHAR(191) NOT NULL, user_id INT NOT NULL,
CREATE TABLE users (
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(191) NOT NULL
);
CREATE TABLE images (
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
url VARCHAR(191) NOT NULL,
user_id INT NOT NULL,
FOREIGN KEY (user_id) REFERENCES users(id)
ON DELETE CASCADE ON UPDATE CASCADE
);
case class User(name: String, imageUrls: Array[String])
val u = Q.query[String, User]("""
SELECT
users.name, images.url
FROM
users
INNER JOIN images ON images.user_id = users.id
WHERE
users.name = ?
""").first(name)
还有一个case类,如下所示:
CREATE TABLE users (
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(191) NOT NULL
);
CREATE TABLE images (
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
url VARCHAR(191) NOT NULL,
user_id INT NOT NULL,
FOREIGN KEY (user_id) REFERENCES users(id)
ON DELETE CASCADE ON UPDATE CASCADE
);
case class User(name: String, imageUrls: Array[String])
val u = Q.query[String, User]("""
SELECT
users.name, images.url
FROM
users
INNER JOIN images ON images.user_id = users.id
WHERE
users.name = ?
""").first(name)
是否可以编写查询和隐式GetResult
,以便执行以下操作:
CREATE TABLE users (
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(191) NOT NULL
);
CREATE TABLE images (
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
url VARCHAR(191) NOT NULL,
user_id INT NOT NULL,
FOREIGN KEY (user_id) REFERENCES users(id)
ON DELETE CASCADE ON UPDATE CASCADE
);
case class User(name: String, imageUrls: Array[String])
val u = Q.query[String, User]("""
SELECT
users.name, images.url
FROM
users
INNER JOIN images ON images.user_id = users.id
WHERE
users.name = ?
""").first(name)
一对多的关系是一件棘手的事情。不确定是否有任何现成的方法允许
GetResult
将记录向下折叠,以便图像URL按用户id聚合到单个用户
记录上。但您可以通过对示例进行一些调整来自行处理:
case class User(name: String, imageUrls: List[String])
val records = Q.query[String, (String,String)]("""
SELECT
users.name, images.url
FROM
users
INNER JOIN images ON images.user_id = users.id
WHERE
users.name = ?
""").list(name)
val users = records.groupBy(_._1).map(tup => User(tup._1, tup._2.map(_._2)))
完成后,您将有一个
Iterable[User]
作为users
val.这里的一对多关系很棘手。不确定是否有任何现成的方法允许GetResult
将记录向下折叠,以便图像URL按用户id聚合到单个用户
记录上。但您可以通过对示例进行一些调整来自行处理:
case class User(name: String, imageUrls: List[String])
val records = Q.query[String, (String,String)]("""
SELECT
users.name, images.url
FROM
users
INNER JOIN images ON images.user_id = users.id
WHERE
users.name = ?
""").list(name)
val users = records.groupBy(_._1).map(tup => User(tup._1, tup._2.map(_._2)))
完成后,您将有一个Iterable[User]
作为users
val