## sharepoint online – create a one-to-many relationship between two columns in separate lists with thousands of variations

I have a library with thousands of files. Each of these files is a broadcast.

I have a separate list that contains all of the ID numbers for the individual box / freight within each shipment. This list also contains a column with the shipment arrival ID.

How can I connect these two together?
I thought it was incredibly easy, but apparently not.

## Django: Right way to access data from a one-to-many relationship?

I'm having trouble accessing data through a one-to-many relationship. After 3 tedious days, I found a way to display the data from the relationship by overriding the get_context_data method. I was wondering if that's the right way. It works, but I could imagine that there is a better way that I missed in the documentation.

Here is the code for it:

``````class QuestionDetailView(DetailView):
model = Question

def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
return context
``````

Here is the code for the models:

`````` class Question(models.Model):
text = models.CharField(max_length=120, unique=True)

``````

Here is the code in my template:

``````    {% extends "base.html" %}
{% block body %}

{{ object.text }}

{%empty%}
{% endfor %}

{% endblock %}
``````

## One-to-many relationship to get the last records plus one column from the previous record

Table 1

``````ProductID   Status
PD_1       OPN
PD_2       CLS
``````

Table 2

``````Table2_id   ProductID   Amount
1           PD_1        900
2           PD_1        800
3           PD_2        1000
4           PD_2        900
5           PD_2        700
``````

Final expected result

``````ProductID   Recent_Amount   Previous_Amount   Status
PD_1        900             800               OPN
PD_2        1000            900               CLS
``````

## mysql – one-to-many relationship with Django

Hello colleagues, I have these models in which I save an invoice with their descriptions. In this case, I have to save several descriptions for one invoice

``````  class Descripciones(models.Model):
descripcion = models.CharField(max_length=255)
referencia = models.CharField(max_length=255)
valorUnitario = models.FloatField()
valorTotal = models.FloatField()
``````

I want to save two descriptions on the same invoice

``````descripcion= Descripciones(
descripcion=desc,
referencia = ref,
valorUnitario=valU,
valorTotal= total
)
descripcion.save()

descripcion2 = Descripciones(
descripcion=desc2,
referencia = ref2,
valorUnitario=valU2,
valorTotal= total2
)
descripcion2.save()

factura= Factura(
fechaInicio = fi,
fechaFin= ff,
cliente = cliente,
empresa = empresa,
descripcion = descripcion,
resol1 =r1,
resol2= r2,
resol3= r3,
resol4= r4,
p0003= p0003,
subTotal = st,
descuento =0,
totalSinIva = st,
iva = iv,
total = st + iv
)
factura.save()
``````

I need to know how to keep two descriptions on the same invoice in a one-to-many relationship ??????????????????

## One-to-many vertex matching in two-part graphs?

By definition, when matching in a bipratite graph, no edges should share the same vertex, i.e. H. It is a one-to-one mapping (vertices).

I have a problem that shows one to many key points. Do you know what this problem is called and how I can solve it?

## Create a one-to-many function of points

I am looking for a way to create a one-to-many function from points.
$$x in 0, 1$$
$$y in (0, n), n in N$$

So, I have points like
$$(0,1), (0,2), (1,3), (1,4)$$
and I need a function that connects them.

The function accepts x and returns the set y.

something like sin ^ (- 1) does it.

Do you know where to look for such an algorithm?

## postgresql – Efficiently find the ultimate parent in multilevel one-to-many tables

Suppose I have a database of multilevel one-to-many tables (a fictitious example):

``````CREATE TABLE users (
id SERIAL PRIMARY KEY
);

CREATE TABLE properties (
id SERIAL PRIMARY KEY,
user_id INTEGER NOT NULL REFERENCES users(id)
);

CREATE TABLE rooms (
id SERIAL PRIMARY KEY,
property_id INTEGER NOT NULL REFERENCES properties(id)
)

CREATE TABLE rates (
id SERIAL PRIMARY KEY,
price INTEGER NOT NULL,
room_id INTEGER NOT NULL REFERENCES rooms(id)
)
``````

For example, suppose a user wants to update that `price` in the `rates` But I want to make sure that he is allowed to – d. H `rate` belongs to a `room` that belongs to one `property` that the user owns.

What would be the best / most efficient way to do this? Is there a way to add a deduced `user_id` Column to `rates` Table that is automatically filled when the rows are added to the table `rates` Table so I can use it later in a query like the following:

``````UPDATE rates SET price=100 WHERE (id=30) AND (user_id=1)`
``````

## Java – Lazy Initialization Exception with 2 entities with the same OnetoMany Lazy Load column in session

I get one `Lazy Initialization` Exception for a `onetomany` associated column in idle state. It is not the usual `session` not found problem or `eager and lazy` on . Please go through the scenario below

I have a Basic Entity class with me `discriminator` column specified therein. There are two child entity classes for different discriminator values.

base class

``````@DiscriminatorColumn("cust_type")
@Table(name = "CUSTOMER_PROFILE")
Customer
{

@OneToMany(fetch = FetchType.LAZY, cascade = { CascadeType.ALL }) @JoinColumn(name = "common_id", referencedColumnName = "common_id")
private Set CommonIdentifier = new HashSet();

}
``````

Child class 1 with discriminator value TYPE 1

``````@Entity(name="CustomerType1")
@DiscriminatorValue("TYPE1")
CustomerType1 extends Customer
{
@ManyToOne(optional = true) @JoinColumn(name = "type2_id") private CustomerType2Entity customerType2; // fetch eager
}
``````

Child class 1 with discriminator value TYPE 2

``````@Entity(name="CustomerType2")
@DiscriminatorValue("TYPE2")
CustomerType2 extends Customer
{

}
``````

Here the CUSTOMER with discriminator Type 1 has a join column `type2_id` which is actually referenced to the same table but to one `Customer` with different discriminator value.

Even in the base class, there is one `onetomany` pillar `common_id` ,

Now there is a scenario in which the customer Type 1 pictured on Type 2 both have the same common_id which is `lazy set.` Then I'll get `Type1` Customer automatically `Type2` will also pick.

Everything works fine if there are different common_id for these 2 customers. But if both have the same common_id, then if I load Type1.CommonIdentifier lazy, I get a lazy initialization exception because there are 2 entities with the same collection with the same ID there `hibernate Session`,

How can I solve this problem? A redesign is not possible `table` or do `CommonIdentifier` `Eager` as a legacy application.

## sql – One-to-many relationship design

In my design of the database, I notice the following case:

I have `men` in a table that can be assigned `Employee` O `vehicles`that are in their respective tables.

The relationship I have to make is one too many. My doubt in the design is whether I should create a table, for example `equipment_assigned` with the fields: `TEAM_ID`.`employee_id`.`id_vehicle` and if I assign a team to an employee, leave the id_vehicle field null, and if I assign a team to a vehicle, leave the id_employed field null.

I would like to know if this is accepted in the design or if there is a better solution for this type of case

## postgresql – Defining and querying tables with mutually exclusive one-to-many relationships

Hello, I am the following situation.

I have 5 tables

``````entity
------------
identity
Entity
...
...
idCountry_fkey
idRegion_fkey
idAggregate_fkey

country
---------------
idCountry
country name

region
---------------
idCountry_fkey
idRegion
region name

aggregate
---------------
idAggregate
Aggregate name

Aggregate_to_Country
----------------------
IDAC
idCountry_fkey
idAggregate_fkey
``````

I've enforced mutual exclusivity with the following restriction on the entity table

``````                CHECK (
(("idAggregate" IS NULL) AND ("idRegion" IS NULL) AND ("idCountry" IS NOT NULL))
OR
(("idAggregate" IS NULL) AND ("idRegion" IS NOT NULL) AND ("idCountry" IS NULL))
OR
(("idAggregate" IS NOT NULL) AND ("idRegion" IS NULL) AND ("idCountry" IS NULL))
);
``````

I have following questions:

1. Is this the right way to deal with this situation?
2. How do I query to have:
``````index | Entity Name | Aggregate | Country | Region | value
-------------------------------------------------- --------
case1 | A | Eurozone | null | null | 1
-------------------------------------------------- --------
case2 | B | LATAM | Brazil | null | 22
-------------------------------------------------- --------
case3 | C | Europe | Italy | Lazio | 44
``````
1. Case 1) when the unit is connected to the unit
2. Case 2) If entity is
by country, and the country is in an aggregated case
3. Case 3) If the entity is connected to the region and the region is connected to a country and the country is in an aggregate