I would like to remove features from layers when using Openlayers3. I know that we can feature.setId(id) when create features and get with feature.getId() to remove them. But if the features is loading from the database or geoserver, they don't have a proper 'ID' Property.
So is a way to remove the selected features without setting feature id?
You have to make your question more clear.
Do you want to delete the features from the DB or you just want to remove them from the client and take no further action on the DB?????
If you dont have an id I guess there should be something identical amoung the feature attributes. I mean if you executed an sql delete script wouldnt you use an identifier to delete them????
So I pressume your features have a primary key or something identical to distinguish them.
So lets assume your fetaures have an identical column named "MYPK". If so you can iterate throught features and grap this identical attribute
var pksToDelete = new Array();
for (var i=0;i<features.length;i++){
pksToDelete.push(features[i].get('MYPK'));
}
now you have all the unique ids of your features into an array.
If you want to delete them from DB go for a wfs-t request using these ids and then do a refresh to your layer.
Better provide a sample code you use and explain in detail your purpose so I can help you in detail.
Related
I have a problem where I need to select a specific value from a specific entity from a entity set, however, I need to do it in a way without knowing the key.
This is the query I actually need:
odata/..../picklistLabels(locale='en_GB',optionId=10819)/label
However I need to program it in a way so it automatically selects the label without knowing the optionId. Is there a way to do this in OData?
From your question, I think that you want to perform a navigation but you don't have a key. Unfortunately, this exact functionality isn't available, however, you can perform an expand like this:
odata/..../picklistLabels?$filter=locale eq 'en_GB' and optionId=10819&$expand=label
This will get you the same information that the other call would do but in a slightly different format, you would have to find the first element in the array and then get the label property to get that information
As an aside, if you have the option to change the server (I'm guessing not due to the sapui5 tag but it might be useful for other users) you could change the key. If the locale and the optionId are enough to identify the object, then you could make these into a composite key. Here is a link for an example within the WebAPI OData source code: https://github.com/OData/ODataSamples/tree/master/WebApi/v4/ODataCompositeKeySample
Dear SAPUI5 Developers,
I developed a SAPUI5 Fiori Worklist project by using WebIDE template projects.
In the Component.js file the OData model has been fetched.
var sServiceUrl = this.getMetadata().getManifestEntry("sap.app").dataSources.mainService.uri;
var oModel = new sap.ui.model.odata.ODataModel(sServiceUrl, {
json: true,
loadMetadataAsync: true
});
oModel.attachMetadataFailed(function() {
// Call some functions from APP controller to show suitable message
}, this);
this.setModel(oModel, "BrandSet");
This part of code causes a call to OData server to fetch data from the remote server.
Now I want to order the data in backend and then receive the data. Assume the sorting function has been implemented correctly in the backend.
Thus, if I use $orderby=name or $orderby=price it has to be sorted by name or price respectively.
In some toturial they said for ordering use sorter option inside of the XML view file. Like here:
https://sapui5.hana.ondemand.com/#docs/guide/c4b2a32bb72f483faa173e890e48d812.html
Now my questions are:
How to apply this sorting inside of the Component.js file where the Model is initiated?
The second question is how to apply this ordering when we apply a filter to the model? Like the example that in the following link applied filter:
https://sapui5.hana.ondemand.com/#docs/guide/5295470d7eee46c1898ee46c1b9ad763.html
In fact I am looking for a function or any kind of method that add the $orderby=xxx to the OData service call.
I found a way here: https://sapui5.hana.ondemand.com/docs/api/symbols/sap.ui.model.odata.ODataModel.html#constructor
If I use mParameters.serviceUrlParams then I can add some URL parameter to the service request but it has been said "these parameters will be attached to all requests". Does it mean if I add the $orderbywith this method then I can not get rid of that in the further requests on that data model for example for filtering?
An app would normally be structured a bit differently to what you propose. The general assumption is that there is a lot of data available from the backend and to load all this data at once can cause performance problems, particularly when used over a mobile phone network. Furthermore, the data is an oData Entity Set, that is, a list of many items of the same type, so the data would be presented in the UI with a list or table.
Typically the app would then show the data in some kind of list, such as sap.m.List or sap.m.Table. These controls are designed to work with large volumes of data and would load initially the first 20 items from the entity set. Only when the user scrolls down the list of data would additional items be loaded. Also, with these controls the user can decide to sort or filter the data according to certain fields in your data.
Assuming that your app is work like this, here is the standard approach.
The Main model (as defined in the manifest) would not be loaded in Component.js, but loaded via the binding defined in the xml views of the app. In the views you could define a fixed sort and/or filter in the binding or you could allow the user to set the sort and filter criteria. This would be handled programmatically in the respective controllers. Normally the changes that the user makes to the sort and filter would be applied separately. For example, he/she chooses an new sort order, the oData is reread and the new sort order shown in the UI. Then the user may chose a filter criteria, and this is applied too. Of course, in your programming logic in the controllers you would need to have applied any default sort and filter criteria and then maybe combine or replace these with the criteria selected by the user.
To see an example of this, I would suggest to look at the Template Application “SAP Fiori Master-Detail Application” in the WebIDE.
I have requirement like this.I can drag and drop my one Order list to another.
and Save also into Data base.
Again when reload same format will be display.
I want to store Parameter like
DocumentCategory,
DocumentName,
Ordering
any one can give the idea class structure and table structure?
This really depends on the database you're using. However, if you decide to use MySQL, you can use this library that I put together recently to automate the whole process of storing/retrieval of user-defined classes. It also contains support for nested classes. Hope this helps!
I have something like a Customer object with up to 50000 order in an ICollection<Orders>.
Assume the Custome being in the local cache, the orders not. How can i delete the Cutomer and all of its related orders without loading all of the Customer orders into the cache and marking them with setDeleted()?
What is the best practice here. I assume extending the public SaveResult SaveChanges(JObject saveBundle) method is the best way. Any other possibilities here on the client side like a flag delete_all_navigation_too()?
Thanks
I must suppose that you do not have and do not want cascade delete on your database. Personally, I'm "terrified" of deletes in general and try to avoid them. I prefer a soft delete (marking a record as inactive). But not everyone agrees or can follow suit
I would consider adding a Web API method (say "DeleteCustomerAndOrders") to your controller to do it. You can call any API method from your client, not just a Breeze method.
In recommending this, I'm assuming that this kind of thing is a relative rarity in your app. You don't need a general purpose deleter, a deleter that takes an array of parent object IDs, a deleter that will delete some child objects and not others, ... etc., etc.
Follow this path and you will have moved the problem from the client to the server. That's good: you didn't have to load the orders on the client. Now you have to get rid of them on the server. If you're using Entity Framework, you face the same challenge of deleting the orders without loading them. Check out Alex James' solution: Bulk-deleting in LINQ to Entities.
Simplest approach that I can come up with is to create a cascade delete constraint on the database so that when a customer is deleted all of its orders get deleted as well. Then simply delete the customer on the client and call 'SaveChanges'. In addition, since Breeze does not yet support client side 'cascaded' deletes ( we are considering this one), you will need to iterate over any client side orders that are already loaded and 'detach' them.
I am quite sure I've seen the answer to this question somewhere, but as I couldn't find it with a couple of searches on SO or google, I ask it again anyway...
In Entity Framework, the only way to delete a data object seems to be
MyEntityModel ent = new MyEntityModel();
ent.DeleteObject(theObjectToDelete);
ent.SaveChanges();
However, this approach requires the object to be loaded to, in this case, the Controller first, just to delete it. Is there a way to delete a business object referencing only for instance its ID?
If there is a smarter way using Linq or Lambda expressions, that is fine too. The main objective, though, is to avoid loading data just to delete it.
It is worth knowing that the Entity Framework supports both to Linq to Entities and Entity SQL. If you find yourself wanting to do deletes or updates that could potentially affect many records you can use the equivalent of ExecuteNonQuery.
In Entity SQL this might look like
Using db As New HelloEfEntities
Dim qStr = "Delete " & _
"FROM Employee"
db.ExecuteStoreCommand(qStr)
db.SaveChanges()
End Using
In this example, db is my ObjectContext. Also note that the ExecuteStoreCommand function takes an optional array of parameters.
I found this post, which states that there really is no better way to delete records. The explanation given was that all the foreign keys, relations etc that are unique for this record are also deleted, and so EF needs to have the correct information about the record. I am puzzled by why this couldn't be achieved without loading data back and forth, but as it's not going to happen very often I have decided (for now) that I won't bother.
If you do have a solution to this problem, feel free to let me know =)
Apologies in advance, but I have to question your goal.
If you delete an object without ever reading it, then you can't know if another user has changed the object in between the time you confirmed that you wanted to delete the object and the actual delete. In "plain old SQL", this would be like doing:
DELETE FROM FOO
WHERE ID = 1234
Of course, most people don't actually do this. Instead, they do something like:
DELETE FROM FOO
WHERE ID = 1234
AND NAME = ?ExpectedName AND...
The point is that the delete should fail (do nothing) if another user has changed the record in the interim.
With this, better statement of the problem, there are two possible solutions when using the Entity Framework.
In your Delete method, the existing instance, compare the expected values of the properties, and delete if they are the same. In this case, the Entity Framework will take care of writing a DELETE statement which includes the property values.
Write a stored procedure which accepts both the IDE and the other property values, and execute that.
There's a way to spoof load an entity by re-calculating it's EntityKey. It looks like a bit of a hack, but might be the only way to do this in EF.
Blog article on Deleting without Fetching
You can create an object with the same id and pass it through to the delete
BUT its good for simple objects if you have complex relations you may need more than that
var user = new User { ID = 15 };
context.Entry(user).State = EntityState.Deleted;
context.SaveChanges();
var toDelete = new MyEntityModel{
GUID = guid,
//or ID = id, depending on the key
};
Db.MyEntityModels.Attach(toDelete);
Db.MyEntityModels.DeleteObject(toDelete);
Db.SaveChanges();
In case your key contains multiple columns, you need to provide all values (e.g. GUID, columnX, columnY etc).
Have also a look here for a generic function if you feel for something fancy.
With Entity Framework 5 there is Entity Framework Extended Library. Available on NuGet. Then you can write something like:
context.Users.Delete(u => u.Id == id);
It is also useful for bulk deletes.