Slick 3.1.1 没有创建唯一约束

Question

我有一个简单的用户 table，其中 id 设置为自动递增，并且 username 设置为在 table 中唯一。

class Users (tag: Tag) extends Table[User](tag, "Users") {

  def id = column[Int]("id", O.PrimaryKey, O.AutoInc)
  def username = column[String]("username", NotNull)
  def email = column[String]("email")
  def passwordHash = column[String]("password_hash")
  def createdAt = column[Long]("created_at")
  def updatedAt = column[Long]("updated_at")
  def lastLoggedInAt = column[Long]("last_logged_in_at")

  override def * = (id.?, username, email, passwordHash, createdAt, updatedAt, lastLoggedInAt) <> (User.tupled, User.unapply)

  def idxUsername = index("idx_username", username, unique = true)
}

但是当使用 slick (db.run(users.schema.create)) 创建 table 时，不会在数据库

上创建唯一索引 idx_username

这是模式 users.schema.createStatements.foreach(println):

的创建语句

create table `Users` (`id` INTEGER NOT NULL AUTO_INCREMENT PRIMARY KEY,`username` TEXT NOT NULL,`email` TEXT NOT NULL,`password_hash` TEXT NOT NULL,`created_at` BIGINT NOT NULL,`updated_at` BIGINT NOT NULL,`last_logged_in_at` BIGINT NOT NULL)
create unique index `idx_username` on `Users` (`username`,`email`)

数据库查询用户索引Table

mysql> SHOW INDEX FROM Users;
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| users |          0 | PRIMARY  |            1 | id          | A         |           0 |     NULL | NULL   |      | BTREE      |         |               |
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
1 row in set (0.00 sec)

我在执行 DDL 函数时是否缺少创建唯一约束的内容？

Answer 1

TEXT 列不能用作 UNIQUE。如果你尝试，

db.run(users.schema.create).onFailure{
  case x => println("error " + x)
}

它将打印，

error com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: BLOB/TEXT column 'username' used in key specification without a key length

作为解决方法，您可以指定类型和长度，

def username = column[String]("username", O.SqlType("VARCHAR(65535)"))

Slick 3.1.1 没有创建唯一约束

Slick 3.1.1 not creating unique constraint

mysql

scala

database-schema

slick-3.0