I am currently trying to write a generic deletion method for embedded documents in MongoEngine. I thought it would be possible to access the document object that contains an embedded document and define the delete function based on the parent document.
The delete function could then possibly look like this:
def delete():
{parent_document}.update(pull__myField={self})
I'm not quite sure yet if this will really work the way I imagine it will but I think it's worth a try. The only thing I don't know yet is how to access the document in which the embedded document exists. So basically I have to somehow access the document referenced as parent_document in the code above from the embedded document.
Does anyone have any idea how to do this? Maybe it's a bad idea in general if someone thinks so, just let me know.
If you want to access to parent document, you can use self._instance in embedded document.
https://github.com/MongoEngine/mongoengine/issues/63
Related
is there a simple and efficient/fast way to query a managedobjectcontext to get an array of all the managedobjects in the context that have not yet been added to the persistent store?
i ask this because i would like to be able to save nsmanagedobjects that have been added to the MOC only if they conform to certain criteria. basically i want to be able to do this so that if some unexpected event happened before my managed object attributes were properly populated, i can catch this fact and purge the object(s) before saving the context. given the complexity of the navigation possible in the app, i'd like to have a look at the data to be sure they are good before i save.
i suppose i could also do this with some kind of validation rule and a flag field that doesn't get set until i am sure the user has added all the data to the record, but i don't yet know how to implement this...
any help much appreciated.
The insertedObjects method of NSManagedObjectContext
returns the set of objects that have been inserted into the context but not yet saved in a persistent store.
Say, organisation has an attachment document. Can I associate this attachment to parent organisation via plugin?
I know another annotation can be created for parent record and file attachment can be copied there. But I'd like to avoid storing copies of attached file.
In short, copying is your only option to have the annotation appear in both records.
The way Annotations are designed completely blocks this reasonable possibility. The Annotation "has-a" Object, even though in forms Objects are presented as the parent of Annotation. So we're stuck with the duplication.
You could always write your own microsoft-unsupported schema scripts and a web resource form control... Be sure to share with the community if you do :)
I am currently playing around with node.js and MongoDB using the node-mongo-native driver.
I tested a bit around using the Mongo console storing and retrieving JS objects. I figured out, that if I store an object that contains functions/methods the methods and functions will also be stored in the collection. This is interesting since I thought that functions could not be stored in MongoDB (with the exception of the system.js collection, as suggested by the Mongo docs).
Also it will not only store the methods but actually each method and member of the object's entire prototype chain. Besides that I dont like this behaviour and think it's unintuitive I mustn't have it.
I was going to manage users in a Mongo collection. To do this I have a User object containing all of the users methods functioning as a prototype for each instance of an user. The user object itself would only contain the users attributes.
If I store a user in the Mongo collection I only want to store the own properties of the user object. No prototype members and especially no prototype methods. Currently I do not see how to cleanly do this. The options that I figured might work are:
creating a shallow copy using foreach and hasOwnProperty and storing this copy in the collection.
Add a data attribute to each user that contains all the object's attributes and can be stored in the collection.
This just came to my mind writing this: I could also set all the prototypes properties to not enumerable which should prevent them from being stored in the collection.
However, I do have the same issues the other way around: when loading a user from a collection. AFAIK there is no way to change an objects prototype in JavaScript after it was created. And there's also no way to specify a prototype to use when Mongo instantiates objects it retrieved from a collection. So basically I always get objects that inherit from Object using Mongo. As far as I can tell I have 2 options to restore a usable user object from this point on:
Create a fresh object inheriting from User and copying each attribute on the result object to the newly created object. (Compatible to storing mechanisms 1 & 3)
Create a fresh object inheriting from User and storing the result object as a data attribute on the newly created object. (Compatible to storing mechanism 2)
Are my assumptions, especially about the possibility to specify a prototype for query results, correct? What's the right way to do it, and why? I'm surely not the first person struggling to store and resurrect objects in/from MongoDB using node.js.
Currently I would go with the approach 2/2. I don't really like it, but it is the most efficient and the only one that works cleanly with the API. However, I'd much rather hear that actually the API does nothing wrong, but I do for not knowing how to use it correctly. So please, enlighten me :)
I just recently realized, that it actually is possible to change an objects prototype in V8/node. While this is not in the standard it is possible in various browsers and especially in V8/node!
function User(username, email) {
this.username = username;
this.email = email;
}
User.prototype.sendMail = function (subject, text) {
mailer.send(this.email, subject, text);
};
var o = {username: 'LoadeFromMongoDB', email: 'nomail#nomail.no'};
o.__proto__ = User.prototype;
o.sendMail('Hello, MongoDB User!', 'You where loaded from MongoDB, but inherit from User nevertheless! Congratulations!');
This is used all over various modules and plugins - even core modules make use of this technique, allthough it is not ECMAScript standard. So I guess it is safe to use within node.js.
I'm not sure I'm following you question exactly... but fwiw one thing came to mind: Have you checked out the Mongoose ORM? (http://mongoosejs.com/)
It gives you a lot of options when it comes to defining models and methods. In particular "Virtuals" might be of interest (http://mongoosejs.com/docs/virtuals.html).
Anyway, hope it helps some!
We have the sharepoint 2010 environment with Document ID's enabled.
Given (part of) a Doc ID, we want to programmatically retrieve the document(s) matching that ID. The problem seems to be that this column is rather special, in that it might need special handling.
Using an SPSiteDataQuery, fetching the _dlc_DocId field as part of the viewfields works fine. However, including it as part of the where query never results in any documents being fetched.
Using the Search API has gotten us nowhere at all.
Has anyone pulled this off, or any suggestions on how to tackle this problem?
[Update] Turns out we were fooled by subtle errors in the XML and bad debugging misinterpretations. This stuff just works fine.
I don't normally contribute to these sorts of things because cleverer people than I always get there before me, but as this is an old one with no proper answer I think I'll add my thoughts for those who find this page.
I was struggling with this but after a little digging around and learning a bit of Caml I got this working.
I am using the SharePoint Client Object Model against SharePoint 2010 and Office365 beta.
Start off your query by looking at the all list items query:
Microsoft.SharePoint.Client.CamlQuery.CreateAllItemsQuery().ViewXml
"<View Scope=\"RecursiveAll\">\r\n <Query>\r\n </Query>\r\n</View>"
Stick a where child inside the query
Then add in
<Eq><FieldRef Name="_dlc_DocId" /><Value Type="Text">MDXC2KE55ASN-3-80</Value></Eq>
replacing MDXC2KE55ASN-3-80 with the doc ID you are looking for inside the where.
Also don't forget you might want to make use of these too:
<ViewFields><FieldRef Name="_dlc_DocId" /></ViewFields>
<RowLimit>1</RowLimit>
Then use List.GetItems() method to bring back the ListItemCollection.
Just in case nobody comes with a slick solutions from the depths of the Sharepoint infrastructure:
What would Google Do?
Slice is, Dice it and dump it in a reverse index.
Solr and Lucene offer supreme tools for this. The idea is to cut the DocId's in small pieces and add the location of the document to the bucket for that piece.
Say We have "A real nice document" with Id ABCD123. You would add it to the buckets
ABCD, BCD1, CD12, D123
When searching for a partial ID (+ other data like dates, types, ...) you (well the search engine) creates the union of the buckets + applies additonal constraints.
To make this happen you need to write a spider for the sharepoint server and a routine which makes a record of data elements to be indexed.
Put a nice REST interface in frnt of it (actually SOLR already has that), integrate it in the main sharepoint server, and nobody needs to know there is something else running behind it.
These products can also incrementally update the indexes, so they can be kept up to date.
you could use the following to get the Document ID.
SPFile file = MethodToUploadFileToServer(web, filepath);
SPListItem item = file.Item;
string DocID = item.Properties["_dlc_DocId"].ToString();
I am doing a workflow for a document library. I put a OnWorkflowItemChanged, and I want to get the value of the column which is changed. I use the workflowProperties.Item["name"] and use the afterProperties. But when I use the workflowProperties.Item["column name"], I still got the original value. When I use the afterProperties, it's NULL.
Then I make another workflow that is the same as above for a list. I can use the workflowProperties.Item["column name"] to get the new value in OnWorkflowItemChanged.
Has anyone come across this problem before? Can you give me some help?
The question seems to mix up Item with ExtendedProperties. As to why a difference is seen on a List/Document Lib, it might have something to do with versionining or perhaps the internal serialization is different. Anyway, some of my experience is outline below. I hope it may be of use:
Use the GUID (as a Guid object, not a string) to access the Before / After ExtendedProperties field. Using the Display Name in the ExtendedProperties will not work. The documentation on it is wrong. You can use SPList.Fields to go from Display Name to Column ID (Guid).
I bind all "Before" to MyWhatever_PreviousProperties and all "After" to MyWhatever_Properties, only accessing MyWhatever_[Previous]Properties after the appropriate event(s)).