数据导出

本节介绍用于导出点、边的方法。

export()

导出图中的点或边。

参数

• exportRequest: ExportRequest：导出请求的配置，包括dbType、schema、selectProperties和graph。
• listener: RequestType.ExportListener：导出数据时执行的回调函数。

返回值

• 无

// Exports 'account' nodes in the graph 'miniCircle'

const exportRequest = new ExportRequest();
exportRequest.setDbType(DBType.DBNODE);
exportRequest.setSchema("account");
exportRequest.setGraph("miniCircle");
exportRequest.addSelectProperties("_id");
exportRequest.addSelectProperties("name");
exportRequest.addSelectProperties("year");
exportRequest.setLimit(100);

const allNodes: any[] = [];

await conn.export(exportRequest, {
  stream: {
    onStart: () => {
      console.log("Export started");
    },
    onData: async (data) => {
      allNodes.push(...data);
    },
    onEnd: () => {
      console.log("Export completed. Total nodes:", allNodes.length);

      if (allNodes.length === 0) {
        console.log("No data received.");
        return;
      }

      try {
        const csv = parse(allNodes);
        const filePath = "./account_nodes.csv";
        fs.writeFileSync(filePath, csv, "utf8");
        console.log(`CSV export completed: ${filePath}`);
      } catch (err) {
        console.error("Failed to write a row to CSV:", err);
      }
    },
  },
});

Export started
Export finished. Total nodes: 111
CSV export completed: ./account_nodes.csv

导出文件account_nodes.csv将保存到与执行文件相同的目录中。

完整示例

import { UltipaDriver } from "@ultipa-graph/ultipa-driver";
import { ULTIPA } from "@ultipa-graph/ultipa-driver/dist/types";
import {
  DBType,
  ExportRequest,
} from "@ultipa-graph/ultipa-driver/src/proto/ultipa_pb";

import * as fs from "fs";
import { parse } from "json2csv";

let sdkUsage = async () => {
  // URI example: ultipaConfig.hosts: ["mqj4zouys.us-east-1.cloud.ultipa.com:60010"]
  const ultipaConfig: ULTIPA.UltipaConfig = {
    hosts: ["192.168.1.85:60061", "192.168.1.87:60061", "192.168.1.88:60061"],
    username: "<username>",
    password: "<password>"
  };

  const conn = new UltipaDriver(ultipaConfig);
  const isSuccess = await conn.test();
  console.log(`Connection succeeds: ${isSuccess}`);

  // Exports 'account' nodes in the graph 'miniCircle'

  const exportRequest = new ExportRequest();
  exportRequest.setDbType(DBType.DBNODE);
  exportRequest.setSchema("account");
  exportRequest.setGraph("miniCircle");
  exportRequest.addSelectProperties("_id");
  exportRequest.addSelectProperties("name");
  exportRequest.addSelectProperties("year");
  exportRequest.setLimit(100);

  const allNodes: any[] = [];

  await conn.export(exportRequest, {
    stream: {
      onStart: () => {
        console.log("Export started");
      },
      onData: async (data) => {
        allNodes.push(...data);
      },
      onEnd: () => {
        console.log("Export completed. Total nodes:", allNodes.length);

        if (allNodes.length === 0) {
          console.log("No data received.");
          return;
        }

        try {
          const csv = parse(allNodes);
          const filePath = "./account_nodes.csv";
          fs.writeFileSync(filePath, csv, "utf8");
          console.log(`CSV export completed: ${filePath}`);
        } catch (err) {
          console.error("Failed to write a row to CSV:", err);
        }
      },
    },
  });
};

sdkUsage().catch(console.error);