协调并行事务

driver.execute_query("<QUERY 1>")

# subsequent execute_query calls will be causally chained

driver.execute_query("<QUERY 2>") # can read result of <QUERY 1>
driver.execute_query("<QUERY 3>") # can read result of <QUERY 2>

driver.execute_query(
    "<QUERY>",
    bookmark_manager_=None,
)

with driver.session() as session:
    session.execute_write(lambda tx: tx.run("<QUERY 1>"))
    session.execute_write(lambda tx: tx.run("<QUERY 2>"))  # can read QUERY 1
    session.execute_write(lambda tx: tx.run("<QUERY 3>"))  # can read QUERY 1,2

from neo4j import GraphDatabase, Bookmarks


URI = "<URI for Neo4j database>"
AUTH = ("<Username>", "<Password>")

def main():
    with GraphDatabase.driver(URI, auth=AUTH) as driver:
        driver.verify_connectivity()
        create_some_friends(driver)


def create_some_friends(driver):
    saved_bookmarks = Bookmarks()  # To collect the sessions' bookmarks

    # Create the first person and employment relationship
    with driver.session(database="neo4j") as session_a:
        session_a.execute_write(create_person, "Alice")
        session_a.execute_write(employ, "Alice", "Wayne Enterprises")
        saved_bookmarks += session_a.last_bookmarks()  (1)

    # Create the second person and employment relationship
    with driver.session(database="neo4j") as session_b:
        session_b.execute_write(create_person, "Bob")
        session_b.execute_write(employ, "Bob", "LexCorp")
        saved_bookmarks += session_b.last_bookmarks()  (1)

    # Create a friendship between the two people created above
    with driver.session(
        database="neo4j", bookmarks=saved_bookmarks
    ) as session_c:  (2)
        session_c.execute_write(create_friendship, "Alice", "Bob")
        session_c.execute_read(print_friendships)


# Create a person node
def create_person(tx, name):
    tx.run("MERGE (:Person {name: $name})", name=name)


# Create an employment relationship to a pre-existing company node
# This relies on the person first having been created.
def employ(tx, person_name, company_name):
    tx.run("""
        MATCH (person:Person {name: $person_name})
        MATCH (company:Company {name: $company_name})
        CREATE (person)-[:WORKS_FOR]->(company)
        """, person_name=person_name, company_name=company_name
    )


# Create a friendship between two people
def create_friendship(tx, name_a, name_b):
    tx.run("""
        MATCH (a:Person {name: $name_a})
        MATCH (b:Person {name: $name_b})
        MERGE (a)-[:KNOWS]->(b)
        """, name_a=name_a, name_b=name_b
    )


# Retrieve and display all friendships
def print_friendships(tx):
    result = tx.run("MATCH (a)-[:KNOWS]->(b) RETURN a.name, b.name")
    for record in result:
        print("{} knows {}".format(record["a.name"], record["b.name"]))


if __name__ == "__main__":
    main()

driver.execute_query("<QUERY 1>")

with driver.session(
    bookmark_manager=driver.execute_query_bookmark_manager
) as session:
    # every query inside this session will be causally chained
    # (i.e., can read what was written by <QUERY 1>)
    session.execute_write(lambda tx: tx.run("<QUERY 2>"))

# subsequent execute_query calls will be causally chained
# (i.e., can read what was written by <QUERY 2>)
driver.execute_query("<QUERY 3>")