ArangoDB是一個多模型數據庫,它支持圖、文檔和鍵值對數據模型。在ArangoDB中,遍歷策略用于查詢圖中的節點和邊。以下是幾種常用的遍歷策略:
dfs
函數實現深度優先搜索。示例:
const { Database, aql } = require('@arangodb');
const db = new Database();
db.useBasicAuth('username', 'password');
const graph = db._collection('myGraph');
const startNode = 'startNodeId';
const dfs = `
function(node) {
return [
{
vertex: node,
edge: 'follow',
direction: 'out'
},
{
vertex: node,
edge: 'like',
direction: 'in'
}
];
}
`;
const result = graph.dfs(startNode, {
startVertex: startNode,
visit: dfs,
depthLimit: 10
});
bfs
函數實現廣度優先搜索。示例:
const { Database, aql } = require('@arangodb');
const db = new Database();
db.useBasicAuth('username', 'password');
const graph = db._collection('myGraph');
const startNode = 'startNodeId';
const bfs = `
function(node) {
return [
{
vertex: node,
edge: 'follow',
direction: 'out'
},
{
vertex: node,
edge: 'like',
direction: 'in'
}
];
}
`;
const result = graph.bfs(startNode, {
startVertex: startNode,
visit: bfs,
depthLimit: 10
});
paths
函數實現路徑遍歷。示例:
const { Database, aql } = require('@arangodb');
const db = new Database();
db.useBasicAuth('username', 'password');
const graph = db._collection('myGraph');
const startNode = 'startNodeId';
const endNode = 'endNodeId';
const maxLength = 10;
const paths = `
function(start, end, maxLength) {
const visited = new Set();
const result = [];
function traverse(node, path) {
if (visited.has(node)) {
return;
}
visited.add(node);
path.push(node);
if (node === end) {
result.push(Array.from(path));
} else {
const neighbors = db._query(`FOR v IN ${graph._collection().name} FILTER v._key == "${node}" RETURN v`).next().edges;
for (const edge of neighbors) {
traverse(edge.to, path);
}
}
}
traverse(start, []);
return result;
}
`;
const result = graph.paths(startNode, endNode, maxLength);
在實際應用中,可以根據需求選擇合適的遍歷策略。同時,可以通過限制遍歷深度、過濾邊類型等參數來優化遍歷性能。