本节介绍如何使用gql()和gqlStream()方法在数据库中执行GQL。

GQL（图查询语言）是ISO标准化的图数据库查询语言。详情参阅GQL文档。

gql()

在数据库中执行GQL语句。

参数

• gql: str：待执行的GQL语句。
• config: RequestConfig（可选）：请求配置。

返回值

• Response：请求结果。

# Retrieves 5 movie nodes from the graph 'miniCircle'

requestConfig = RequestConfig(graph="miniCircle")
response = Conn.gql("MATCH (n:movie) RETURN n LIMIT 5", requestConfig)
nodeList = response.alias("n").asNodes()
for node in nodeList:
    print(node.get("name"))

The Shawshank Redemption
Farewell My Concubine
Léon: The Professional
Titanic
Life is Beautiful

gqlStream()

在数据库中执行GQL语句并以增量形式返回结果。在处理大型数据集时，避免同时加载所有数据至内存中。

参数

• gql: str：待执行的GQL语句。
• cb: QueryResponseListener：流处理监听器。
• config: RequestConfig（可选）：请求配置。

返回值

• None

# Retrieves all 1-step paths from the graph 'miniCircle'

requestConfig = RequestConfig(graph="miniCircle")

# Define the event handler functions
def on_start(requestConfig):
    print("Stream started.")

def on_data(res, requestConfig):
    print("Data received:", res)

def on_end(requestConfig):
    print("Stream ended.")

stream = QueryResponseListener()
stream.on("start", on_start)
stream.on("data", on_data)
stream.on("end", on_end)
gql = 'MATCH p = ()-[]-() RETURN p'
result = Conn.gqlStream(gql, stream, requestConfig)
print()

Stream started.
Data received: {'status': <ultipa.types.types.Status object at 0x00000239B87E9FD0>, 'items': {'p': <ultipa.types.types.DataItem object at 0x00000239B87F1790>}, 'aliases': None, 'req': None, 'statistics': <ultipa.types.types.UltipaStatistics object at 0x00000239B87F1760>, 'explainPlan': None}
Stream ended.

完整示例

from ultipa import UltipaConfig, Connection, RequestConfig

ultipaConfig = UltipaConfig()
# URI example: ultipaConfig.hosts = ["mqj4zouys.us-east-1.cloud.ultipa.com:60010"]
ultipaConfig.hosts = ["192.168.1.85:60061", "192.168.1.87:60061", "192.168.1.88:60061"]
ultipaConfig.username = "<username>"
ultipaConfig.password = "<password>"

Conn = Connection.NewConnection(defaultConfig=ultipaConfig)

# Retrieves 5 movie nodes from the graph 'miniCircle'

requestConfig = RequestConfig(graph="miniCircle")
response = Conn.gql("MATCH (n:movie) RETURN n LIMIT 5", requestConfig)
nodeList = response.alias("n").asNodes()
for node in nodeList:
    print(node.get("name"))