Neo4J -通过JavaScript连接时未创建的节点

Question

我试图在neo4j应用程序中向node.js数据库添加一个节点，代码似乎执行得很好，但没有创建任何节点。

这是我的代码：

var neo4j = require('neo4j-driver');

// the rest of my program 

const driver = new neo4j.driver(
  "bolt://localhost:7687",
  neo4j.auth.basic(neouser, neopass)
);
const session = driver.session();
var cypher =
  "MERGE (b:TRIGGER {name:'" +
  rname +
  "'}) MERGE (c:FIELD{name:'" +
  trigger +
  "'}) MERGE (b)<-[:ACTIVATES]-(c)";
try {
  const result = session.run(cypher);
  console.log(result);
} finally {
  console.log("finally");
  session.close();
}
driver.close();

错误的结果是：

Result {
_stack: '\n' +
'    at captureStacktrace (C:\\NGToolbox\\NGToolBox\\node_modules\\neo4j-driver\\lib\\result.js:263:15)\n' +
'    at new Result (C:\\NGToolbox\\NGToolBox\\node_modules\\neo4j-driver\\lib\\result.js:68:19)\n' +
'    at Session._run (C:\\NGToolbox\\NGToolBox\\node_modules\\neo4j-driver\\lib\\session.js:174:14)\n' +
'    at Session.run (C:\\NGToolbox\\NGToolBox\\node_modules\\neo4j-driver\\lib\\session.js:135:19)\n' +
'    at C:\\NGToolbox\\NGToolBox\\routes\\bizrulevis.js:261:30\n' +
'    at Layer.handle [as handle_request] (C:\\NGToolbox\\NGToolBox\\node_modules\\express\\lib\\router\\layer.js:95:5)\n' +
'    at next (C:\\NGToolbox\\NGToolBox\\node_modules\\express\\lib\\router\\route.js:137:13)\n' +
'    at Route.dispatch (C:\\NGToolbox\\NGToolBox\\node_modules\\express\\lib\\router\\route.js:112:3)\n' +
'    at Layer.handle [as handle_request] (C:\\NGToolbox\\NGToolBox\\node_modules\\express\\lib\\router\\layer.js:95:5)\n' +
'    at C:\\NGToolbox\\NGToolBox\\node_modules\\express\\lib\\router\\index.js:281:22',
  _streamObserverPromise: Promise { <pending> },
  _p: null,
  _query: "MERGE (b:TRIGGER {name:'DELETEME.1'}) MERGE (c:FIELD{name:'4001'}) MERGE (b)<-[:ACTIVATES]-(c)",
  _parameters: {},
  _connectionHolder: ConnectionHolder {
    _mode: 'WRITE',
    _database: '',
    _bookmark: Bookmark { _values: [] },
    _connectionProvider: DirectConnectionProvider {
      _id: 3,
      _config: [Object],
      _log: [NoOpLogger],
      _userAgent: 'neo4j-javascript/0.0.0-dev',
      _authToken: [Object],
      _connectionPool: [Pool],
      _openConnections: [Object],
      _address: [ServerAddress]
    },
    _referenceCount: 1,
    _connectionPromise: Promise { <pending> }
  }
}
finally

当我进入Neo4j时，db仍然是空的。

我已经确认它是活动的，我可以使用相同的密码创建一个节点，连接是在安全日志中建立的，并且它不会因为un/pw而失败。一切看起来都很完美，除了所有的一切都没有造成任何问题。

谢谢你的建议。

编辑:添加了驱动程序调用，驱动程序从代码段范围外关闭。

Answer 1

这段代码应该适用于您(假设定义了neouser、neopass、rname和trigger )：

const neo4j = require('neo4j-driver');

async function doIt() {
  const driver = neo4j.driver(
    "bolt://localhost",
    neo4j.auth.basic(neouser, neopass)
  );
  const session = driver.session();

  try {
    await session.writeTransaction(async txc => {
      var result = await txc.run(
        `MERGE (b:TRIGGER {name: $rname})
         MERGE (c:FIELD {name: $trigger})
         MERGE (b)<-[:ACTIVATES]-(c)
         RETURN b, c`,
        {rname: rname, trigger: trigger}
      )

      result.records.map(record => {
          console.log(`b: ${record.get('b')}, c: ${record.get('c')}`);
      })
    })
  } finally {
    console.log("finally");
    await session.close();
    await driver.close();
  }
}

doIt();

此代码了解处理的异步性质，在事务完成后使用result，然后才关闭会话和驱动程序。它还使用writeTransaction向DB写入。

您应该研究驱动程序的github文件，以了解驱动程序可以使用的所有方法。

Answer 2

如果您正在编写API，请尝试使用OGM https://www.npmjs.com/package/neo4j-node-ogm。

class SomeModel extends from Model {} //see documentation

坚持下去

const a = new SomeModel()
await a.save()

告诉我这是否对你有帮助。