CRUD
Create - save
Retrieve - find
Update - update
Delete - remove
db.runCommand( { getLastError : 1 } ) // returns the result of last operation
Create - save
Retrieve - find
Update - update
Delete - remove
- mongodb is a documented oriented data store
- BSON - binary JSON
- BSON Specification with data types
db.runCommand( { getLastError : 1 } ) // returns the result of last operation
> db.ALERT_TABLE.count()
0
> db.runCommand({getLastError:1})
{ "n" : 0, "connectionId" : 136, "err" : null, "ok" : 1 }
The err field would contain an error message had this been an error condition.
When err is null that is an indication that the operation succeeded.
db.people.update( {}, { $set : {title: "Dr"} }, { multi: true} )
var MongoClient = require( mongodb ).MongoClient;
console.dir(Checking findOne with Node.js);
var testFindOne=function() {
console.dir(testFindOne);
MongoClient.connect(mongodb://localhost:27017/course, function(err, db) {
if (err) throw err;
var query = {grade : 100 };
db.collection(grades).findOne(query, function(err,doc) {
if(err) throw err;
console.dir(doc);
db.close();
});
}
);
};
var testFind=function() {
console.dir(testFind);
MongoClient.connect(mongodb://localhost:27017/course, function(err, db) {
if (err) throw err;
var query = {grade : 100 };
db.collection(grades).find(query).toArray(function(err,docs) {
if (err) throw err;
console.dir(docs);
db.close();
});
}
);
};
var testFindWithCursor=function() {
console.dir(testFind);
MongoClient.connect(mongodb://localhost:27017/course, function(err, db) {
if (err) throw err;
var query = {grade : 100 };
var cursor=db.collection(grades).find(query);
cursor.each(function(err,doc) {
if (err) throw err;
if (doc == null) {
return db.close();
}
console.dir(doc.student + " got a good grade!");
});
}
);
};
var testFindWithProjection=function() {
console.dir(testFindWithProjection);
MongoClient.connect(mongodb://localhost:27017/course, function(err, db) {
if (err) throw err;
var query = {grade : 100 };
var projection = {student:1,_id:0};
var cursor=db.collection(grades).find(query,projection);
cursor.each(function(err,doc) {
if (err) throw err;
if (doc == null) {
return db.close();
}
console.dir(doc);
//console.dir(doc.student + " got a good grade!");
});
}
);
};
// testFindOne();
// testFind();
// testFindWithCursor();
testFindWithProjection();
$ node findOneWithNodeJsDriver.js
Checking findOne with Node.js
{ _id: 52e3d5b6fb88577ec1496219,
student: Joe,
assignment: exam,
grade: 100 }
Importing from REDDIT (www.reddit.com/r/technology/.json)
var MongoClient = require(mongodb).MongoClient, request = require(request);
MongoClient.connect(mongodb://localhost:27017/course,function(err,db) {
if (err) throw err;
request(http://www.reddit.com/r/technology/.json, function(error, response, body) {
if (!error && response.statusCode == 200) {
var obj = JSON.parse(body);
var stories = obj.data.children.map(function(story) {return story.data; }
);
db.collection(reddit).insert(stories, function(err,data) {
if(err) throw err;
console.dir(data);
db.close();
});
}
});
});
----
var MongoClient = require(mongodb).MongoClient;
MongoClient.connect(mongodb://localhost:27017/course, function(err, db) {
if(err) throw err;
var query = { title : { $regex : Microsoft } };
var projection = { title : 1, _id : 0 };
db.collection(reddit).find(query, projection).each(function(err, doc) {
if(err) throw err;
if(doc == null) {
return db.close();
}
console.dir(doc.title);
});
});
Dot Notation:
var MongoClient = require(mongodb).MongoClient;
var request = require(request);
var insertReddit=function(page,collection) {
MongoClient.connect(mongodb://localhost:27017/course, function(err, db) {
if (err) {
console.dir("FUNCKSTER");
throw err;
}
var url=http://www.reddit.com/+page+.json;
console.dir("url="+url);
console.dir("request is next");
request(url,function(error,response,body) {
if(!error && response.statusCode == 200) {
console.dir(good neews);
var obj = JSON.parse(body);
// console.dir(obj);
var stuff = obj.data.children.map(function(datum) {
return datum;
});
//console.dir(stuff);
db.collection(collection).insert(stuff,function(err,data) {
if(err) throw err;
console.dir(data);
db.close();
});
}
});
/*
*/
});
};
MongoClient.connect(mongodb://localhost:27017/course, function(err, db) {
if(err) throw err;
var query = { media.oembed.type : video };
var projection = { media.oembed.url : 1, _id : 0 };
db.collection(reddit_front).find(query, projection).each(function(err, doc) {
if(err) throw err;
if(doc == null) {
return db.close();
}
console.dir(doc);
});
});
insertReddit(,reddit_front);
