尝试插入重复记录后，如果不存在则插入失败

Posted 2021-04-21

我使用过this question的解决方案。

我用了接受的答案：

方法

def insertRequiredDocIfNotExists(keys: DocumentInfo) = {
    val documentMasterId = "hardcoded_value 1"
    val documentMasterCategory = "hardcoded value 2"

    val action = {
      RequiredDocuments.filter(_.required_document_id__k === keys.documentId)
        .result
        .headOption
        .flatMap{
          case Some(doc) =>
            logger.debug("Required doc already exists")
            DBIO.successful(doc)
          case None =>
            RequiredDocuments.map(rd => (
              rd.doc_master_list__k,
              rd.doc_category__k,
              rd.applicant_id__k,
              rd.application_id__k,
              rd.name,
              rd.required_document_id__k,
              rd.type_k
            )) += (
              Some("Job Application 1"),
              Some("Resume"),
              Some("Job Applicant 1"),
              Some("Lead for Applicant 1"),
              Some("Resume ID 224"),
              Some("Last 6 months WorkExperience Resume"),
              Some("General")
            )
        }
      }.transactionally

      val db = Connections.getSaleForceSchemaDBObject().db
      db.run(action)
    }

用法

Await.result(insertRequiredDocIfNotExists(keys), Duration.Inf)
// inserts into other tables.

日志

错误消息如下所示：

ERROR: duplicate key value violates unique constraint "hcu_idx_required_document__c_required_document_uuid__c"
Detail: Key (required_document_id__k)=(c63386c0-d599-4d47-a535-941a24a07a6e) already exists.: org.postgresql.util.PSQLException
org.postgresql.util.PSQLException: ERROR: duplicate key value violates unique constraint "required_document_id__k"
Detail: Key (required_document_uuid__c)=(c63386c0-d599-4d47-a535-941a24a07a6e) already exists.
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2433)
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2178)
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:306)
at org.postgresql.jdbc.PgStatement.executeInternal(PgStatement.java:441)
at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:365)
at org.postgresql.jdbc.PgPreparedStatement.executeWithFlags(PgPreparedStatement.java:155)
at org.postgresql.jdbc.PgPreparedStatement.executeUpdate(PgPreparedStatement.java:132)
at slick.jdbc.LoggingPreparedStatement.$anonfun$executeUpdate$5(LoggingStatement.scala:155)
at scala.runtime.java8.JFunction0$mcI$sp.apply(JFunction0$mcI$sp.java:12)
at slick.jdbc.LoggingStatement.logged(LoggingStatement.scala:84)
at slick.jdbc.LoggingPreparedStatement.executeUpdate(LoggingStatement.scala:155)
at slick.jdbc.JdbcActionComponent$InsertActionComposerImpl$SingleInsertAction.$anonfun$run$11(JdbcActionComponent.scala:510)
at slick.jdbc.JdbcBackend$SessionDef.withPreparedStatement(JdbcBackend.scala:386)
at slick.jdbc.JdbcBackend$SessionDef.withPreparedStatement$(JdbcBackend.scala:381)
at slick.jdbc.JdbcBackend$BaseSession.withPreparedStatement(JdbcBackend.scala:448)
at slick.jdbc.JdbcActionComponent$InsertActionComposerImpl.preparedInsert(JdbcActionComponent.scala:501)
at slick.jdbc.JdbcActionComponent$InsertActionComposerImpl$SingleInsertAction.run(JdbcActionComponent.scala:507)
at slick.jdbc.JdbcActionComponent$SimpleJdbcProfileAction.run(JdbcActionComponent.scala:30)
at slick.jdbc.JdbcActionComponent$SimpleJdbcProfileAction.run(JdbcActionComponent.scala:27)
at slick.basic.BasicBackend$DatabaseDef$$anon$2.liftedTree1$1(BasicBackend.scala:275)
at slick.basic.BasicBackend$DatabaseDef$$anon$2.run(BasicBackend.scala:275)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

---

Slick有一个upsert方法，可以更新项目（如果存在）。我不想使用upsert，因为每个周期最多不断更新同一项目20次是没有意义的。

答案

好的，这个问题的一个可能的解决方案是使两端的事务查询您要检查的存在值然后可能插入...考虑到DBIOAction是一个monad，您可以编写您的解决方案，如：

val query = RequiredDocuments.filter(_.required_document_id__k === keys.documentId)

val newRecord = {
  (
    Some("Job Application 1"),
    Some("Resume"),
    Some("Job Applicant 1"),
    Some("Lead for Applicant 1"),
    Some("Resume ID 224"),
    Some("Last 6 months WorkExperience Resume"),
    Some("General")
  )
}

val finalQuery = {
  query.exists.result.flatMap{ exitingRecord =>
    if (!exitingRecord) {
      RequiredDocuments.map{rd => (
        rd.doc_master_list__k,
        rd.doc_category__k,
        rd.applicant_id__k,
        rd.application_id__k,
        rd.name,
        rd.required_document_id__k,
        rd.type_k
      )} += newRecord
    } else {
      DBIO.successful(None)
    }
  }
}
db.run(finalQuery.transactionally)

希望有帮助:)