Im new to Caché and got a problem: I want to save a value into the Relation Column in Class B via Class A and thats not working ...
Currently I am doing it like this
In Class A:
set Obj1 = ##class(This.Is.Class.B).%New()
set Obj1.PID = ..id
set Obj1.PName = ..name
set status = Obj1.%Save(0)
Its saving the PName into Class B but not the PID which I defined as Relationship [One to Many] in Class B
Connection objects in a relationship are bidirectional. But in any case, you can't just set id to such property. You should set object or insert object depending on which side you want to do it. In your case you do it like
do obj1.PIDSetObjectId(..id)
To get more information read the documentation.
Related
My Objective is:
Using MATLAB, set the property value within one class method, and the property values are different between instances.
My Problem is:
When using SET in the class method, I will change the property value of all instances of this class, which is not what I want. I only want to change the property value of this instance.
About the dynamic property: I think it's used to create a unique property of the instance instead of setting the unique value of a general class property, is that right?
Code example:
classdef Storage
properties
tree = containers.Map('KeyType','int32', 'ValueType','any')
end
methods
function obj = set_tree(obj,period, value)
obj.tree(period) = value;
end
end
end
When setting the value using this method:
st1 = Storage();
st2 = Storage();
st1 = st1.set_tree(10,1);
st2 = st2.set_tree(10,2);
Right now, the value set to st2.tree(10) will override the value set to st1.tree(10), which I am trying to avoid.
The problem you're having is caused by setting a handle class object as a default value for a class property. The relevant documentation says this:
MATLAB® evaluates property default values only once when loading the class. MATLAB does not reevaluate the assignment each time you create an object of that class. If you assign an object as a default property value in the class definition, MATLAB calls the constructor for that object only once when loading the class.
So, for your Storage class above, all of your instances will be using the same default containers.Map object stored in the tree property. And since the containers.Map class is a subclass of the handle class it has reference behavior, which means the copies of the object will all point to the same underlying key/value map. If you want independent objects for each instance, you can initialize the tree property in the constructor:
classdef Storage
properties
tree
end
methods
function obj = Storage()
obj.tree = containers.Map('KeyType','int32', 'ValueType','any');
end
function obj = set_tree(obj, value, period)
obj.tree(period) = value;
end
end
end
I have an issue with defining model in spyne to generate several levels "in" SOAP11.
I used example at first, but my task is to generate service for tables already existing, so I got stuck and try to understand wheter to seek in Spyne properties or Sqlalchemy.
To be precise, i'll take example from site and show what i'm trying to reach:
class Permission(TableModel):
__tablename__ = 'permission'
id = UnsignedInteger32(pk=True)
application = Unicode(values=('usermgr', 'accountmgr'))
operation = Unicode(values=('read', 'modify', 'delete'))
perm_user_id = integer
last field is the FK for user table, but its name is different from user_id
class User(TableModel):
__tablename__ = 'user'
id = UnsignedInteger32(pk=True)
user_name = Unicode(32, min_len=4, pattern='[a-z0-9.]+', unique=True)
full_name = Unicode(64, pattern='\w+( \w+)+')
email = Unicode(64, pattern=r'[a-z0-9._%+-]+#[a-z0-9.-]+\.[A-Z]{2,4}')
last_pos = Point(2, index='gist')
permissions = Array(Permission).store_as('table')
--- SQL generated tries to add "WHEN user.id = permission.user_id" but I need another field (perm_user_id) to be filtered
Help me to define class to get correct inner tags.. actually it'll be about 3 more classes deep.
Thanx in Advance, Yury
Your answer is correct. Just as an alternative for simple tables, you can omit column definitions and let sqlalchemy's reflection engine figure it out.
meta = TableModel.Attributes.sqla_metadata
meta.reflect()
class User(TableModel):
__table__ = meta.tables['user']
The User class will be reconstructed using as much information as possible from the table columns and their types.
Found it myself, sorry to disturb anyone,
from spyne.model.complex import table
Permissions= Array(permission).customize(store_as=table(right='perm_user_id'))
I have a method for editing a table (Human) in my database. That table is part of a 1 to many relationship. Human is on the many side.
Human has a foreign key named idOtherTable.
Now, here is how I'm trying to change it:
Employee e = (from x in db.Human
where x.idHuman == someNumber
select x).First();
e.name = name;
e.phoneNumber = phoneNumber;
//this is how I try to change it:
e.RoleReference.EntityKey.EntityKeyValues[0].Value = editEmployee.idRole;
but it says that once is set, the value cannot be changed. How can I resolve this?
I have a situation where I'm trying to filter a LINQ select using a derived sub class.
ctx.BaseEntity.OfType<SubClass>() - this works fine.
However I'd like to do this using a string value instead. I've come across a performance barrier when I have lots (>20) Sub Classes and selecting an Entity without using OfType just isn't an option. I have a generic UI that renders from the base class, so I don't know what Class Type will be returned at compile time.
So what I'd like to do is this:
Perform a projected Select where I
return just the SubClassType from
the database
Perform a second select
using this value as the OfType to
only select the relevant related
entity from the database (No mass
unions generated)
int id = 1;
var classType = (from c in ctx.BaseClass.Include("ClassType")
where c.id == id
select new
{
c.ClassType.TypeName
}).First();
BaseClass caseQuery = ctx.BaseClass.OfType<classType.TypeName>()
.Include("ClassType")
.Include("ChildEntity1")
.Include("ChildEntity2")
.Where(x => x.id== id);
But obviously this won't work because OfType requires a Type and not a string.
Any ideas on how I can achieve this?
Update:
As a side note to the original question, it turns out that the moment you project a query that uses a Navigation Property - it builds the monster SQL too, so I've ended up using a stored procedure to populate my ClassType entity from the BaseClass Id.
So I've just got it to work using eSQL, which I'd never used before. I've posted the code here just in case it helps someone. Has anyone else got a more strongly typed solution they can think of?
BaseClass caseQuery = ctx.BaseClass.CreateQuery<BaseClass>("SELECT VALUE c FROM OFTYPE(Entities.[BaseClass],namespace.[" + classType.TypeName + "]) as c")
.Include("ClassType")
.Include("ChildEntity1")
.Include("ChildEntity2")
.Where(x => x.id== id).FirstOrDefault();
To answer the headline question about calling OfType with a string / runtime type, you can do the following:
// Get the type, assuming the derived type is defined in the same assembly
// as the base class and you have the type name as a string
var typeToFilter = typeof(BaseClass)
.Assembly
.GetType("Namespace." + derivedTypeName);
// The use reflection to get the OfType method and call it directly
MethodInfo ofType = typeof(Queryable).GetMethod("OfType");
MethodInfo ofTypeGeneric = method.MakeGenericMethod(new Type[] { typeToFilter });
var result = (IQueryable<Equipment>)generic.Invoke(null, new object[] { equipment });
Combine this with your stored procedure to get the class name and you (should?) avoid the massive join - I don't have table-per-type implementation to play with so I can't test.
I have two tables in my entity framework, objects, and parameters which have a foreign key pointing to the object to which they belong. I want to populate a tree with all the attributes of a certain object. So in order to find those I want to do this:
String parentObject = "ParentObjectName";
var getAttributes = (from o in myDB.ATTRIBUTE
where o.PARENT_OBJECT == parentObject
select o);
However when I try to do this I get an error saying it cannot convert from type OBJECT to string, even though in the database this value is stored as a string. I have a workaround where I get an instance of the parentObject, then go through every attribute and check whether it's parent_object == parentObjectInstance, but this is much less efficient than just doing 1 query. Any help would be greatly appreciate, thanks!
Well, PARENT_OBJECT.ToString() can't be called (implicitly or explicitly) in L2E, but if it just returns a property, you can look at that directly:
String parentObject = "ParentObjectName";
var getAttributes = (from o in myDB.ATTRIBUTE
where o.PARENT_OBJECT.NAME == parentObject
select o);
...note the .NAME
Try this:
String parentObject = "ParentObjectName";
var getAttributes = (from o in myDB.ATTRIBUTE
where o.PARENT_OBJECT.ToString() == parentObject
select o);