Is it possible to configure NHibernate (specifically Fluent NHibernate) to serialize an array of simple types to a single database column? I seem to remember that this was possible but its been a while since I've used NHibernate.
Essentially I need to store the days of week that a person works (int[]) and would rather not have a separate table just for this purpose.
It is possible.
You need to implement a IUserType that takes care of mapping between your array and a data column (google that first; it's possible that somebody already implemented it)
Alternatively, you can do the conversion in your entity class, and map the single-field representation instead of the property. For example:
string numbers;
public int[] Numbers
{
get { return numbers.Split(','); }
set { numbers = string.Join(",", value.Select(x => x.ToString())); }
}
Yes. There's UserType for scenarios like that. You could also use enum and bit flag.
Related
Looking to achieve the below but it is failing as the locations.Any() is being treated as an IEnumerable instead of an IQueryable and scalar functions invoked via EF require IQueryable. I need this filter to happen at the database level (not materialize the list first).
How can I get the locations.Any() to be treated as an IQueryable here? I understand the list doesn't exist in the database but is there a way for Entity Framework to understand this any and build and AND statement with nested OR in SQL?
public Address GetAddresses(List<Loctions> locations)
{
_context.Addresses.
Where(a => locations.Any(l => MyContext.CustomFunction(l.PropA,l.PropB, a.PropA, a.ProbB) > 1 ))
}
[DbFunction("fn_DistanceBetweenCoordinates", "dbo")]
public static decimal CustomFunction(decimal SourceLatitude, decimal SourceLongitude, decimal TargetLatitude, decimal TargetLongitude) {
throw new NotImplementedException();
}
You could achieve this by moving CustomFunction into the database and use that server side function when querying from EF.
Please read User defined function mapping and try to adapt the sample according to your use case.
We haven't seen the body of the CustomFunction, so it's impossible to tell if it's viable to do the transfer from client based UDF to server based.
We also don't know how the Locations list is populated. Depending on how that is done, the adaptation of the example code might become more cumbersome.
I have POCO classes , I use NewtonSoft json for seralization. Now i want to migrate it to Google protocol buff. Is there any way i can migrate all my classes (not manually) so that i can use google protocol buff for serialization and deseralization.
Do you just want it to work? The absolute simplest way to do this would be to use protobuf-net and add [ProtoContract(ImplicitFields = ImplicitFields.AllPublic)]. What this does is tell protobuf-net to make up the field numbers, which it does by taking all the public members, sorting them alphabetically, and just counting upwards. Then you can use your type with ProtoBuf.Serializer and it should behave in the way you expect.
This is simple, but it isn't very robust. If you add, remove or rename members it can all get out of sync. The problem here is that the protocol buffers format doesn't include names - just field numbers, and it is much harder to guarantee numbers over time. If your type is likely to change, you probably want to define field numbers explicitly. For example:
[ProtoContract]
public class Foo {
[ProtoMember(1)]
public int Id {get;set;}
[ProtoMember(2)]
public List<string> Names {get;} = new List<string>();
}
One other thing to watch out for would be non-zero default values. By default protobuf-net assumes certain things about implicit default values. If you are routinely using non-zero default values without doing it very carefully, protobuf-net may misunderstand you. You can turn that off globally if you desire:
RuntimeTypeModel.Default.UseImplicitZeroDefaults = false;
Currently I am working partly with cfwheels and its Active Record ORM (which is great), and partly raw cfml with its Hibernate ORM (which is also great).
Both work well for applicable situations, but the thing I do miss most when using CF ORM is the model.update() method that is available in cfwheels, where you can just pass a form struct to the method, and it will map up the struct elements with the model properties and update the records.. really good for updating and maintaining large tables. In CF ORM, it seems the only way to to update a record is to set each column individually, then do a save. Is this the case?
Does cf9 ORM have an Active Record type update() (or equivalent) method which can just receive a struct with values to update and update the object without having to specify each one?
For example, instead of current:
member = entityLoadByPK('member',arguments.id);
member.setName(arguments.name);
member.setEmail(arguments.email);
is there a way to do something like this in CF ORM?
member = entityLoadByPK('member',arguments.id);
member.update(arguments);
Many thanks in advance
In my apps I usually create two helper functions for models which handle the task:
/*
* Get properties as key-value structure
* #limit Limit output to listed properties
*/
public struct function getMemento(string limit = "") {
local.props = {};
for (local.key in variables) {
if (isSimpleValue(variables[local.key]) AND (arguments.limit EQ "" OR ListFind(arguments.limit, local.key))) {
local.props[local.key] = variables[local.key];
}
}
return local.props;
}
/*
* Populate the model with given properties collection
* #props Properties collection
*/
public void function setMemento(required struct props) {
for (local.key in arguments.props) {
variables[local.key] = arguments.props[local.key];
}
}
For better security of setMemento it is possible to check existence of local.key in variables scope, but this will skip nullable properties.
So you can make myObject.setMemento(dataAsStruct); and then save it.
There's not a method exactly like the one you want, but EntityNew() does take an optional struct as a second argument, which will set the object's properties, although depending on how your code currently works, it may be clunky to use this method and I don;t know whether it'll have any bearing on whether a create/update is executed when you flush the ORM session.
If your ORM entities inherit form a master CFC, then you could add a method there. Alternatively, you could write one as a function and mix it into your objects.
I'm sure you're aware, but that update() feature can be a source of security problems (known as the mass assignment problem) if used with unsanitized user input (such as the raw FORM scope).
I have an entity, with a field of type enum, that is persisted as an integer in my database.
When retrieving objects from the database using ICriteria, I wish to restrict the results to those with the field being a member of a collection of enum values. Does Restrictions.In work with a collection of enums?
The following does not work. Do I have to perform something like type-casting at the "restrictions.in" part of the query?
var myEnumCollection = new MyEnum[] { MyEnum.One };
return FindAll<MyType>(Restrictions.In("EnumProperty", myEnumCollection));
FindAll is a method encapsulating
criteria.GetExecutableCriteria(Session).List<MyType>()
My initial guess would be that you'll need to compare against the integer values of the enum members (assuming that you're mapping the enum as an integer); so something like:
var myEnumCollection = new int[] { MyEnum.One };
return FindAll<MyType>(Restrictions.In("EnumProperty", myEnumCollection));
May be the solution that you're after. If you update your post with further details (mapping of the enum member and the sql being generated by the query), I may be able to provide further assistance.
Is there a way to use SessionFactory.GetClassMetadata(), or any other method you're aware of, to dynamically get the maximum size of a varchar column that underlies an NHibernate class' string property?
To clarify, I'm not looking to read a length attribute that's specified in the NHibernate mapping file. I want to deduce the actual database column length.
See the code below for two different ways you can get the column size for a string from NHib metadata.
Cheers,
Berryl
[Test]
public void StringLength_DefaultIs_50_v1()
{
_metadata = _SessionFactory.GetClassMetadata(typeof(User));
var propertyType = _metadata.GetPropertyType("Email") as StringType;
Assert.That(propertyType.SqlType.Length, Is.EqualTo(50));
}
[Test]
public void StringLength_DefaultIs_50_v2()
{
var mapping = _Cfg.GetClassMapping(typeof(User));
var col = mapping.Table.GetColumn(new Column("Email"));
Assert.That(col.Length, Is.EqualTo(50));
}
When the Session factory is generated the NH engine does not check (and retrieve) what the underlying database is. For your case either you provide a "rich" mapping to have everything available at runtime, OR make a function that reads the necessary information from the DB (ie select * from sys.columns ..... for sql-server) when you need it.
Mind you that a rich mapping also allows the NH engine to make some automations (like checking if the size of the string passed is larger than the length of the (n)varchar column)