I have used #ManyToOne() relation for status_id and used leftJoin() to join two tables
I m expecting my query response to be returned as
... { "status": "NEW" }
my result shows up like this
... "status" : { "name" : "NEW" }
here is my response object
here is
enquiry_table
here is
enquiry_status_table
here is my query
How do I acheive my expecting result.
Any help
Related
Still learning ES. This is my query:
{
"query": {
"wildcard" : {
"identifier" : "*NZ*"
}
}
}
And I have definitely document with a field named identifier and a string containing NZ. they are returned when I drop the query expression.
But I always receive 0 hits when querying this. Why?
suppose I have a data structure in firebase real time database like
{ "donors" :
"uid1" : { "name" : "x", "bloodGroup" : "A+", "location" : "some Place"},
"uid2" : { "name" : "y", "bloodGroup" : "A-", "location" : "some place"},
...
...
}
now if I have millions of donor records like this. how could I filter them based on bloodGroup location and fetching say 100 records from server at a time using angularfire2.
I have found this page which was really helpful to me when using queries to query my firebase data:
https://howtofirebase.com/collection-queries-with-firebase-b95a0193745d
A very simple example would be along the lines of:
this.donorsData = af.database.list('/donors', {
query: {
orderByChild: 'bloodGroup',
equalTo: 'A+',
}
});
Not entirely sure how to fetch 100 records, then another 100, I am using datatables in my app, which fetches all my data and using the datatables for pagination.
I am using MEAN stack, i have an entry like this in my mongodb
{ "_id" : ObjectId("5577467683f4716018db19ed"),
"requestMatrix" : { "1698005072" : { "rideId" : "641719948", "status" :"accepted" },"1698005073" : { "rideId" : "641719545", "status" :"rejected" } },
"partners":[ { "customerNumber" : 1698005072 }, { "customerNumber" : 1698072688 } ]}
I want to query the db to return me this entire document based on whether the status is accepted or rejected.
When I run the below query in a command prompt, i get the expected answer
db.joinedrides.find({'requestMatrix.1698005072.status':"accepted"})
But when i want to do the same from nodeJs, I am stuck as the number 1698005072 in the above query is a variable, i am not able to write a query for that.
tried something like this
var criteria = "'requestMatrix.'"+customerNumber+"'.status'";
JoinedRide.find({criteria:"accepted"},function(err,joinedRides){
})
where customerNumber will vary for different requests, in the above mentioned case its value is 1698005072
Any help is appreciated.
You need to do something like this:
var query = {};
var criteria = "requestMatrix." + customerNumber + ".status";
query[criteria] = "accepted"
JoinedRide.find(query,function(err,joinedRides){
})
I'm running a blog-style web application on AppFog (ex Nodester).
It's written in NodeJS + Express and uses Mongoose framework to persist to MongoDB.
MongoDB is version 1.8 and I don't know whether AppFog is going to upgrade it to 2.2 or not.
Why this intro? Well, now my "posts" are shown in a basic "paginated" visualization, I mean they're just picked up from mongo, sorted by date descending, a page at a time. Here's a snippet:
Post
.find({pubblicato:true})
.populate("commenti")
.sort("-dataInserimento")
.skip(offset)
.limit(archivePageSize)
.exec(function(err,docs) {
var result = {};
result.postsArray = (!err) ? docs : [];
result.currentPage = currentPage;
result.pages = howManyPages;
cb(null, result);
});
Now, my goal is to GROUP BY 'dataInserimento' and show posts like a "diary", I mean:
1st page => 2012/10/08: I show 3 posts
2nd page => 2012/10/10: I show 2 posts (2012/10/09 has no posts, so I don't allow a white page)
3rd page => 2012/10/11: 35 posts and so on...
My idea is to get first the list of all dates with grouping (and maybe counting posts for each day) then build the pages link and, when a page (date) is visited, query like above, adding date as parameter.
SOLUTIONS:
Aggregation framework would be perfect for that, but I can't get my hands on that version of Mongo, now
Using .group() in some way, but the idea it doesn't work in sharded environments does NOT excite me! :-(
writing a MAP-REDUCE! I think this is the right way to go but I can't imagine how map() and reduce() should be written.
Can you help me with a little example, please?
Thanks
EDIT :
The answer of peshkira is correct, however, I don't know if I need exactly that.
I mean, I will have URLs like /archive/2012/10/01, /archive/2012/09/20, and so on.
In each page, it's enough to have the date for querying for posts. But then I have to show "NEXT" or "PREV" links, so I need to know what's the next or previous day containing posts, if any. Maybe can I just query for posts with dates bigger or smaller than the current, and get the first one's date?
Assuming you have something similar as:
{
"author" : "john doe",
"title" : "Post 1",
"article" : "test",
"created" : ISODate("2012-02-17T00:00:00Z")
}
{
"author" : "john doe",
"title" : "Post 2",
"article" : "foo",
"created" : ISODate("2012-02-17T00:00:00Z")
}
{
"author" : "john doe",
"title" : "Post 3",
"article" : "bar",
"created" : ISODate("2012-02-18T00:00:00Z")
}
{
"author" : "john doe",
"title" : "Post 4",
"article" : "foo bar",
"created" : ISODate("2012-02-20T00:00:00Z")
}
{
"author" : "john doe",
"title" : "Post 5",
"article" : "lol cat",
"created" : ISODate("2012-02-20T00:00:00Z")
}
then you can use map reduce as follows:
Map
It just emits the date as key and the post title. You can change the title to the _id, which will probably be more useful to you. If you store the time of the date you will want to use only the date (without time) as the key, otherwise mongo will group by date time and not only date. In my test case all posts have the same time 00:00:00 so it does not matter.
function map() {
emit(this.created, this.title);
}
Reduce
It does nothing more, then just push all values for a key to an array and then the array is wrapped in a result object, because mongo does not allow arrays to be the result of a reduce function.
function reduce(key, values) {
var array = [];
var res = {posts:array};
values.forEach(function (v) {res.posts.push(v);});
return res;
}
Execute
Using db.runCommand({mapreduce: "posts", map: map, reduce: reduce, out: {inline: 1}}) will output the following result:
{
"results" : [
{
"_id" : ISODate("2012-02-17T00:00:00Z"),
"value" : {
"posts" : [
"Post 2",
"Post 1"
]
}
},
{
"_id" : ISODate("2012-02-18T00:00:00Z"),
"value" : "Post 3"
},
{
"_id" : ISODate("2012-02-20T00:00:00Z"),
"value" : {
"posts" : [
"Post 5",
"Post 4"
]
}
}
],
...
}
I hope this helps
I am looking for a CouchDB equivalent to "SQL joins".
In my example there are CouchDB documents that are list elements:
{ "type" : "el", "id" : "1", "content" : "first" }
{ "type" : "el", "id" : "2", "content" : "second" }
{ "type" : "el", "id" : "3", "content" : "third" }
There is one document that defines the list:
{ "type" : "list", "elements" : ["2","1"] , "id" : "abc123" }
As you can see the third element was deleted, it is no longer part of the list. So it must not be part of the result. Now I want a view that returns the content elements including the right order.
The result could be:
{ "content" : ["second", "first"] }
In this case the order of the elements is already as it should be. Another possible result:
{ "content" : [{"content" : "first", "order" : 2},{"content" : "second", "order" : 1}] }
I started writing the map function:
map = function (doc) {
if (doc.type === 'el') {
emit(doc.id, {"content" : doc.content}); //emit the id and the content
exit;
}
if (doc.type === 'list') {
for ( var i=0, l=doc.elements.length; i<l; ++i ){
emit(doc.elements[i], { "order" : i }); //emit the id and the order
}
}
}
This is as far as I can get. Can you correct my mistakes and write a reduce function? Remember that the third document must not be part of the result.
Of course you can write a different map function also. But the structure of the documents (one definig element document and an entry document for each entry) cannot be changed.
EDIT: Do not miss JasonSmith's comment to his answer, where he describes how to do this shorter.
Thank you! This is a great example to show off CouchDB 0.11's new
features!
You must use the fetch-related-data feature to reference documents
in the view. Optionally, for more convenient JSON, use a _list function to
clean up the results. See Couchio's writeup on "JOIN"s for details.
Here is the plan:
Firstly, you have a uniqueness contstraint on your el documents. If two of
them have id=2, that's a problem. It is necessary to use
the _id field instead if id. CouchDB will guarantee uniqueness, but also,
the rest of this plan requires _id in order to fetch documents by ID.
{ "type" : "el", "_id" : "1", "content" : "first" }
{ "type" : "el", "_id" : "2", "content" : "second" }
{ "type" : "el", "_id" : "3", "content" : "third" }
If changing the documents to use _id is absolutely impossible, you can
create a simple view to emit(doc.id, doc) and then re-insert that into a
temporary database. This converts id to _id but adds some complexity.
The view emits {"_id": content_id} data keyed on
[list_id, sort_number], to "clump" the lists with their content.
function(doc) {
if(doc.type == 'list') {
for (var i in doc.elements) {
// Link to the el document's id.
var id = doc.elements[i];
emit([doc.id, i], {'_id': id});
}
}
}
Now there is a simple list of el documents, in the correct order. You can
use startkey and endkey if you want to see only a particular list.
curl localhost:5984/x/_design/myapp/_view/els
{"total_rows":2,"offset":0,"rows":[
{"id":"036f3614aeee05344cdfb66fa1002db6","key":["abc123","0"],"value":{"_id":"2"}},
{"id":"036f3614aeee05344cdfb66fa1002db6","key":["abc123","1"],"value":{"_id":"1"}}
]}
To get the el content, query with include_docs=true. Through the magic of
_id, the el documents will load.
curl localhost:5984/x/_design/myapp/_view/els?include_docs=true
{"total_rows":2,"offset":0,"rows":[
{"id":"036f3614aeee05344cdfb66fa1002db6","key":["abc123","0"],"value":{"_id":"2"},"doc":{"_id":"2","_rev":"1-4530dc6946d78f1e97f56568de5a85d9","type":"el","content":"second"}},
{"id":"036f3614aeee05344cdfb66fa1002db6","key":["abc123","1"],"value":{"_id":"1"},"doc":{"_id":"1","_rev":"1-852badd683f22ad4705ed9fcdea5b814","type":"el","content":"first"}}
]}
Notice, this is already all the information you need. If your client is
flexible, you can parse the information out of this JSON. The next optional
step simply reformats it to match what you need.
Use a _list function, which simply reformats the view output. People use them to output XML or HTML however we will make
the JSON more convenient.
function(head, req) {
var headers = {'Content-Type': 'application/json'};
var result;
if(req.query.include_docs != 'true') {
start({'code': 400, headers: headers});
result = {'error': 'I require include_docs=true'};
} else {
start({'headers': headers});
result = {'content': []};
while(row = getRow()) {
result.content.push(row.doc.content);
}
}
send(JSON.stringify(result));
}
The results match. Of course in production you will need startkey and endkey to specify the list you want.
curl -g 'localhost:5984/x/_design/myapp/_list/pretty/els?include_docs=true&startkey=["abc123",""]&endkey=["abc123",{}]'
{"content":["second","first"]}