交易

API

如果您想在一個交易中執行多個陳述式，請使用 transaction 函數。

val players = listOf<Player>()
database.playerQueries.transaction {
  players.forEach { player ->
    database.playerQueries.insert(
      player_number = player.number,
      full_name = player.fullName
    )
  }
}

若要從交易中回傳值，請使用 transactionWithResult 函數。

val players: List<Player> = database.playerQueries.transactionWithResult {
  database.playerQueries.selectAll().executeAsList()
}

回溯

如果交易中任何地方發生例外狀況，交易將會回溯。您可以在交易的任何內部手動回溯交易，但如果您的交易回傳值，您將需要為交易指定一個回傳值。

database.playerQueries.transaction {
  players.forEach { player ->
    if (player.number == 0) rollback()
    database.playerQueries.insert(
      player_number = player.number,
      full_name = player.fullName
    )
  }
}

val numberInserted: Int = database.playerQueries.transactionWithResult {
  players.forEach { player ->
    if (player.number == 0) rollback(0)
    database.playerQueries.insert(
      player_number = player.number,
      full_name = player.fullName
    )
  }
  players.size
}

回呼

您可以註冊回呼，使其在交易完成或回溯後執行：

database.playerQueries.transaction {
  afterRollback { log("No players were inserted.") }
  afterCommit { log("${players.size} players were inserted.") }

  players.forEach { player ->
    database.playerQueries.insert(
      player_number = player.number,
      full_name = player.fullName
    )
  }
}