kotlin - 有没有办法用 Kotlin 的 Exposed 库运行原始 sql

Question

我正在尝试运行一些特定于 postgres 的 sql，并希望在 Exposed 中重用事务管理。

Answer 1

Exposed 有Transaction.exec(String)可能做你想要的方法。见https://github.com/JetBrains/Exposed/blob/master/exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/mysql/MysqlTests.kt

Answer 2

在 Kiskae 的回答的帮助下，我能够运行原始 sql：

transaction {
     val conn = TransactionManager.current().connection
     val statement = conn.createStatement()
     val query = "REFRESH MATERIALIZED VIEW someview"
     statement.execute(query)
}

Answer 3

import java.sql.*
import org.jetbrains.exposed.sql.*
import org.jetbrains.exposed.sql.transactions.*

fun getAccId(db : Database, acc_domain: String) {
  transaction(db) {
    addLogger(StdOutSqlLogger)
    var acc_id: Long = 0
    exec("select id from accounts where domain = '${acc_domain}'") { rs ->
        while(rs.next()) {
          acc_id = rs.getLong("id")
        }
    }
    println("Acc Id is ${acc_id}")
  }
}

val database = Database.connect(datasource)
getAccId(database,"mytest.test.io")

Answer 4

这是一个带参数的示例：

transaction(database) {
   val conn = TransactionManager.current().connection
   val query = "update user set name = ? where id = ?";
   val statement = conn.prepareStatement(query, false)
   statement.fillParameters(listOf(Pair(VarCharColumnType(), "Laura"),
      Pair(IntegerColumnType(), 3)));
   statement.executeUpdate()
}

Answer 5

您可以创建一个简单的辅助函数，例如：

String.execAndMap(transform : (ResultSet) -> T) : List {
         val 结果 = arrayListOf()
         TransactionManager.current().exec(this) { rs ->
              而（rs.next（））{
                   结果 += 变换（rs）
              }
         }
         返回结果
    }

    "select u.name, c.name from user u inner join city c where blah blah".execAndMap { rs ->
        rs.getString("u.name") 到 rs.getString("c.name")
    }

取自：https ://github.com/JetBrains/Exposed/wiki/FAQ#q-is-it-possible-to-use-native-sql--sql-as-a-string