I've got a class that closely resembles one of my entities (I use the class for JSON de/serialization because the entity fails conversion to JSON, one of the known gotchyas of JSON + MVC).
Once I deserilize a JSON string into my object, is there a way to automatically update the associated Entity model instance. The property names are the same.
e.g.
'myDeserialized is the deserialized JSON object coming over the wire
Dim entityInstance As DLL.Person = db.getPersonById(myDeserialized.id)
myDeserialized.update(entityInstance)
Where this just goes through and takes all the properties in myDeserialized and updates the same named property in entityInstance?
Or is it possible to just iterate over a key-value pair of all the properties in an object/entity?
I'm looking for something like TryUpdateModel(), but that only works with forms, right? I don't want to tie my data to a form, that's all.
Thanks!
I don't know what type and version of EF you use, but there are very powerful functions for iterating on the entities properties. Which mean you can easily make your update function on the entity or its baseclass' partial (entityInstance.Update(myDesrialized)).
If you use EntityObject, then you can get an ObjectStateEntry for your entities and via this class you can very easily achieve this.
Please let us know what version and type of EF you use (POCO?)
Related
I'm new to Kotlin, so apologies if I'm not articulating concepts correctly. I have an instance of an Entity
[TestEntity(applicationId=1, timestamp=2018-01-24T18:40:30, issueState=MA, product=test, status=sold, paymentMode=VISA, premium=null)]
I am writing a service that is going to take these keys and use them to create the headers of a report. The keys may change depending on the type of report the user is trying to generate, which will have an impact on the Entity that will be instantiated.
I want to be able to iterate over this Entity so that I can create an array to use for the headers. Any thoughts on how I do this?
I think the cleanest solution is storing values in a map and delegating properties to it.
Don't think you can otherwise iterate over class fields without some verbose getter chain or ugly reflection shenanigans.
For example here you can access map fields as if they were class fields, but can also easily iterate over map.
data class TestEntity(val map : Map<String, Any>){
val appId : Int by map
val timeStamp : Long by map
(... more fields)
}
In my SDN 4 project I have a following Cypher query(a part of query):
(entity)<-[:COMMENTED_ON]-(comg:CommentGroup)
for example I can get id of entity with a following Cypher function id(entity)
How to get entity name or class name ?
Use the labels function
match (entity)<-[:COMMENTED_ON]-(comg:CommentGroup) return id(entity), labels(entity)
For each row returned, you'll get the Neo4j id and array of labels.
Assuming your NodeEntity class labels match at least one of these labels, you can then iterate and load the appropriate class instance yourself.
Generally speaking you shouldn't need to do this however.
If (entity) is polymorphic, SDN/OGM will hydrate the correct objects for you. It pretty much does under the hood what I described above, but it also handles matching on interfaces, subclasses, etc.
I used the CRUD generator from a legacy database. When searching for a column value I get the following error:
htmlspecialchars() expects parameter 1 to be string, array given (/usr/local/share/yii/framework/web/helpers/CHtml.php:103)
The problem is that the model has an existing column named "attributes" which is creating a conflict. I removed the entry from the _search.php and commented out all instances in the model hoping to at least get it working but no luck. Any suggestions would be appreciated.
Thanks.
Every CActiveRecord instance (or CModel instance for that matter) has a getter/setter named attributes with which all the attributes can be set. This leads to a conflict because the generated crud code uses the attributes attribute expecting it works as described before.
The controller does something like:
$model->attributes=$_POST['ModelClassName'];
// or
$model->attributes=$_GET['ModelClassName'];
This is meant to set al the (safe) attributes of the model at once. Instead this overwrites the database attribute attributes of your legacy DB model.
This in turn leads to the error you describe, because $_GET['ModelClassName'] and $_POST['ModelClassName'] typically contain arrays of data.
I guess the easiest fix would be to directly call the setter function for the "normal" attributes behavior which would lead to replacing the lines mentioned above with something like the following:
// in the controller
$model->setAttributes($_POST['ModelClassName']);
// and
$model->setAttributes($_GET['ModelClassName']);
I think rest of the generated CRUD code (the views) could and should be left untouched to make it work.
If you want to know how and why this works, it's best to do some research into the __get and __set magic functions and how they're used in the yii framework.
I am using Model-Glue/Coldspring for a new application and I thought I would throw CF9 ORM into the mix.
The only issue I am having right now is with populating an entity with an object. More or less the code below verifies that only one username can exist. There is some other logic that is not displayed.
My first thought was to using something like this:
var entity = entityload('UserAccount' ,{UserName=arguments.UserAccount.getUserName()},"true")
entity = arguments.UserAccount;
How ever this does not work the way that I expected. Is it even possible to populate an entity with an object or do I need to use the setters?
Not sure if this is what you're looking for. If you have...
component persistent="true" entityName="Foo"
{
property a;
property b;
}
You can pass a struct in the 2nd param to init the entity (added in CF9.0.1 I believe)
EntityNew("Foo", {a="1",b="2"});
To populate Foo with another object, you can use the Memento pattern, and implement a GetMemento() function to your object that returns a struct of all its properties.
EntityNew("Foo", bar.getMemento());
However, CF does NOT call your custom setters! If you want to set them using setters, you may add calls to the setters in your init() constructor, or use your MVC framework of choice to populate the bean. In Model-Glue, it is makeEventBean().
Update: Or... Here's hack...
EntityNew("Foo", DeserializeJSON(SerializeJSON(valueObject)));
Use this at your own risk. JSON might do weird things to your numbers and the 'yes','no','true','false' strings. :)
Is it even possible to populate an entity with an object or do I need to use the setters?
If you mean "Is it possible to create load an ORM Entity from an instance of that persistent CFC that already exists and has properties set?", then yes you can using EntityLoadByExample( object,[unique] )
entity = EntityLoadByExample( arguments.userAccount,true );
This assumes the userAccount CFC has been defined as persistent, and its username value has been set before being passed in (which seems to be the case in your situation).
Bear in mind that if any other properties have been set in the object you are passing, including empty strings, they will be used as filters to load the entity, so if they do not exactly match a record in your database, nothing will be loaded.
Ok so I'm trying to use the JavaScriptSerializer to work with this code. However it crashes when it reaches the last line;
Dim json As New String(sr.Serialize(dt))
I get this error message;
A circular reference was detected
while serializing an object of type
'System.Reflection.Module'.
I would really appreciate any insights that could help solve this problem.
Circular reference means that serialising the object would result in an infinite loop.
For example if you would try to serialize object "A" having a 1 to 1 reference to object "B".
Declare a class containg the data you want to serialize with JSON to solve this issue.
As hkda150 has already said, you could use a class specifically tailored for being serialized.
This will furthermore enable you to have foreign key values serialized instead of having related full objects serialized. Thus, if you are serializing object a which has a property a.SomeB of type B, then you will often want the ID of a.someB to be present in your webpage. Obviously I don't know enough to be able to say if this is relevant in your specific use case.
BTW, If you find yourself doing a lot of mapping between "business objects" and "objects meant for serialization" you may want to consider using AutoMapper.