[英]How do I access inserted document's _id within a transaction in ArangoDB
在事務中,我看不到任何訪問已插入/已更新文檔密鑰的示例。
var collections = {write: ['foo','bar']};
var action = String(function () {
var doc = params['doc'];
var relatedDoc = params['relatedDoc'];
var db = require('internal').db;
db.foo.save(doc); // how do I access the _id, key etc of the newly inserted doc?
relatedDoc.foos.push(doc._id); // _id does not exist yet
db.bar.save(relatedDoc);
return {success: true};
});
var params = {
doc: doc,
relatedDoc: relatedDoc
};
db.transaction(collections, action, params, function (err, result) {
if (err) {
return dfd.reject(err);
}
return dfd.resolve(result);
});
collection.save()
方法將為保存的文檔返回一些元數據:
_rev
:文檔修訂版ID(由服務器自動生成) _key
:文檔密鑰(由用戶在_key
屬性中指定,或者由服務器自動生成) _id
:與鍵相同,但還包含集合名稱 要在代碼中使用生成的ID,可以在變量中捕獲collection.save()
的結果,並按以下方式使用它:
var collections = {write: ['foo','bar']};
var action = String(function () {
var doc = params['doc'];
var relatedDoc = params['relatedDoc'];
var db = require('internal').db;
var newDoc = db.foo.save(doc); // capture result of save in newDoc
relatedDoc.foos.push(newDoc._id); // use newDoc._id for
db.bar.save(relatedDoc);
return {success: true};
});
var params = {
doc: doc,
relatedDoc: relatedDoc
};
db.transaction(collections, action, params, function (err, result) {
if (err) {
return dfd.reject(err);
}
return dfd.resolve(result);
});
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