协调并行事务

await driver.executeQuery('<QUERY 1>')

// subsequent executeQuery calls will be causally chained

await driver.executeQuery('<QUERY 2>') // can read result of <QUERY 1>
await driver.executeQuery('<QUERY 3>') // can read result of <QUERY 2>

await driver.executeQuery(
    '<QUERY>',
    {},
    {
      bookmarkManager: null
    }
)

let session = driver.session({database: '<database-name>'})
try {
  await session.executeWrite(async tx => {
    await tx.run("<QUERY 1>")
  })
  await session.executeWrite(async tx => {
    await tx.run("<QUERY 2>")  // can read result of QUERY 1
  })
  await session.executeWrite(async tx => {
    await tx.run("<QUERY 3>")  // can read result of QUERY 1, 2
  })
} finally {
  await session.close()
}

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

(async () => {
  const URI = '<URI to Neo4j database>'
  const USER = '<username>'
  const PASSWORD = '<password>'
  let driver
  try {
    driver = neo4j.driver(URI, neo4j.auth.basic(USER, PASSWORD))
    await driver.verifyConnectivity()
  } catch(err) {
    console.log(`-- Connection error --\n${err}\n-- Cause --\n${err.cause}`)
    return
  }
  await createFriends(driver)
})()

async function createFriends(driver) {
  let savedBookmarks = []  // To collect the sessions' bookmarks

  // Create the first person and employment relationship.
  const sessionA = driver.session({database: '<database-name>'})
  try {
    await createPerson(sessionA, 'Alice')
    await employPerson(sessionA, 'Alice', 'Wayne Enterprises')
    savedBookmarks.concat(sessionA.lastBookmarks())  (1)
  } finally {
    sessionA.close()
  }

  // Create the second person and employment relationship.
  const sessionB = driver.session({database: '<database-name>'})
  try {
    await createPerson(sessionB, 'Bob')
    await employPerson(sessionB, 'Bob', 'LexCorp')
    savedBookmarks.concat(sessionB.lastBookmarks())  (1)
  } finally {
    sessionB.close()
  }

  // Create (and show) a friendship between the two people created above.
  const sessionC = driver.session({
    database: '<database-name>',
    bookmarks: savedBookmarks  (2)
  })
  try {
    await createFriendship(sessionC, 'Alice', 'Bob')
    await printFriendships(sessionC)
  } finally {
    sessionC.close()
  }
}

// Create a person node.
async function createPerson(session, name) {
  await session.executeWrite(async tx => {
    await tx.run('CREATE (:Person {name: $name})', { name: name })
  })
}

// Create an employment relationship to a pre-existing company node.
// This relies on the person first having been created.
async function employPerson(session, personName, companyName) {
  await session.executeWrite(async tx => {
    await tx.run(`
      MATCH (person:Person {name: $personName})
      MATCH (company:Company {name: $companyName})
      CREATE (person)-[:WORKS_FOR]->(company)`,
      { personName: personName, companyName: companyName }
    )
  })
}

// Create a friendship between two people.
async function createFriendship(session, nameA, nameB) {
  await session.executeWrite(async tx => {
    await tx.run(`
      MATCH (a:Person {name: $nameA})
      MATCH (b:Person {name: $nameB})
      MERGE (a)-[:KNOWS]->(b)
      `, { nameA: nameA, nameB: nameB }
    )
  })
}

// Retrieve and display all friendships.
async function printFriendships(session) {
  const result = await session.executeRead(async tx => {
    return await tx.run('MATCH (a)-[:KNOWS]->(b) RETURN a.name, b.name')
  })
  for(record of result.records) {
    console.log(`${record.get('a.name')} knows ${record.get('b.name')}`)
  }
}

await driver.executeQuery('<QUERY 1>')

session = driver.session({
    bookmarkManager: driver.executeQueryBookmarkManager
})
try {
  // every query inside this session will be causally chained
  // (i.e., can read what was written by <QUERY 1>)
  await session.executeWrite(async tx => tx.run('<QUERY 2>'))
} finally {
  await session.close()
}

// subsequent executeQuery calls will be causally chained
// (i.e., can read what was written by <QUERY 2>)
await driver.executeQuery('<QUERY 3>')