执行UQL

本节介绍如何使用Uql()和UQLStream()方法在数据库中执行UQL。

UQL由嬴图开发，用于操作嬴图数据库。详情参阅UQL文档。

Uql()

在数据库中执行UQL语句。

参数

• uql: str：待执行的UQL语句。
• config: *configuration.RequestConfig（可选）：请求配置。

返回值

• Response：请求结果。
• error：包含操作过程中遇到的任何问题的错误对象；如果操作成功，则返回nil。

// Retrieves 5 movie nodes from the graph 'miniCircle'

requestConfig := &configuration.RequestConfig{
  Graph: "miniCircle",
}

response, _ := driver.Uql("find().nodes({@movie}) as n return n{*} limit 5", requestConfig)
nodeList, _, _ := response.Alias("n").AsNodes()
for _, node := range nodeList {
  fmt.Println(node.Get("name"))
}

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

UQLStream()

在数据库中执行UQL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

• uql: string：待执行的UQL语句。
• cb: func(*http.Response) error：用于处理流式传入的http.Response的回调函数；如果处理过程中出现问题，返回错误。
• config: *configuration.RequestConfig（可选）：请求配置。

返回值

• error：包含操作过程中遇到的任何问题的错误对象；如果操作成功，则返回nil。

import (
    ...
	sdkhttp "github.com/ultipa/ultipa-go-sdk/sdk/http" // renamed to avoid conflict
    ...
)

...

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

requestConfig := &configuration.RequestConfig{
    Graph: "miniCircle",
}

fmt.Println("Stream started.")

cb := func(resp *sdkhttp.Response) error {
    // Print query statistics
    printers.PrintStatistics(resp.Statistic)

    // Try to parse response as paths (assuming RETURN p yields paths)
    paths, err := resp.Get(0).AsPaths()
    if err != nil {
        fmt.Println("Error parsing paths:", err)
        return err
    }

    for i, p := range paths {
        fmt.Printf("Path %d: %+v\n", i+1, p)
    }
    return nil
}

uql := "n().e().n() as p return p"
err = driver.UQLStream(uql, cb, requestConfig)
if err != nil {
    log.Fatalln("Stream error:", err)
}

fmt.Println("Stream ended.")

Stream started.
Total Cost : 0.67s | Engine Cost : 0s
Path 1: &{NodeUUIDs:[6196955286285058158 7998395137233256563] EdgeUUIDs:[2356] Nodes:map[6196955286285058158:0xc0009e7950 7998395137233256563:0xc0009e7ad0] Edges:map[2356:0xc00029e6e0]}
Path 2: &{NodeUUIDs:[6196955286285058158 9223377534412914884] EdgeUUIDs:[2524] Nodes:map[6196955286285058158:0xc0009e7e30 9223377534412914884:0xc000a14030] Edges:map[2524:0xc00029ed70]}
...
Path 237: &{NodeUUIDs:[18302634383191834827 17942343114467311744] EdgeUUIDs:[2633] Nodes:map[17942343114467311744:0xc0004d3a70 18302634383191834827:0xc0004d38c0] Edges:map[2633:0xc0005374f0]}
Stream ended.

完整示例

package main

import (
	"fmt"
	"log"

	"github.com/ultipa/ultipa-go-sdk/sdk"
	"github.com/ultipa/ultipa-go-sdk/sdk/configuration"
)

func main() {
	config := &configuration.UltipaConfig{
		// URI example:	Hosts: []string{"mqj4zouys.us-east-1.cloud.ultipa.com:60010"},
		Hosts:    []string{"192.168.1.85:60061", "192.168.1.87:60061", "192.168.1.88:60061"},
		Username: "<usernmae>",
		Password: "<password>",
	}

	driver, err := sdk.NewUltipaDriver(config)
	if err != nil {
		log.Fatalln("Failed to connect to Ultipa:", err)
	}

	// Retrieves 5 movie nodes from the graph 'miniCircle'

	requestConfig := &configuration.RequestConfig{
		Graph: "miniCircle",
	}

	response, _ := driver.Uql("find().nodes({@movie}) as n return n{*} limit 5", requestConfig)
	nodeList, _, _ := response.Alias("n").AsNodes()
	for _, node := range nodeList {
		fmt.Println(node.Get("name"))
	}
}