About Relations (associations, association_meta)

Hey there!

About a weekend and some later, and I am much more confident in my driver - I feel like it's maturing, and so is the accompaning REL implementation. So, I have started to write some playground-style tests to see how far it works ... or does not.

Right now, I am trying to get related record loading to work; so let me give you the TL;DR:

```surrealql
DEFINE TABLE users SCHEMAFULl;
DEFINE FIELD name ON users TYPE string;
DEFINE FIELD tags ON users TYPE array;
DEFINE FIELD photos ON users TYPE record;

DEFINE TABLE photos SCHEMAFULL;
DEFINE FIELD title ON photos TYPE string;
DEFINE FIELD file ON photos TYPE bytes;
```

That's a very basic 1:n relation. To query all users, with their photos:

```surrealql
SELECT * FROM users FETCH photos;
```

The resulting JSON will _also_ contain the photos - as already attached objects.
```js
{
"id": "user:test",
"name": "Test User",
"tags": ["dev", "nerd"],
"photos": [
{
"id": "photos:abcdef",
"title": "A selfie",
"data": [...]
},
{
"id": "photos:zyxvut",
"title": "Another selfie",
"data": [...]
}
]
}
```

This obviously isn't how the big classics, MySQL and PostgresQL behave.

The way the driver handles it, is that it returns both `tags` and `photos` as `[]byte`.

This is demonstrated [here](https://github.com/IngwiePhoenix/surrealdb-driver/blob/878b0906b1fd4f44dc4706d0a2469285b9a00c92/pkg/rel/testing/ex2/main.go#L80). Unfortunately, inserting data does not work: `Found NONE for field `risks_rel`, with record `processes:Lohnabrechnung2`, but expected a record`. That's a SurrealDB error, and here is the query that produced that:

```
surrealdb:driver:connection:execWithArgs INSERT INTO processes (title, description, responsible, risks, storage, id, created_at, updated_at, legal_basis, tasks, affected_data) VALUES ($_1, $_2, $_3, $_4, $_5, $_6, $_7, $_8, $_9, $_10, $_11) ON DUPLICATE KEY UPDATE storage = $_12, title = $_13, description = $_14, responsible = $_15, risks = $_16, tasks = $_17, affected_data = $_18, id = $_19, created_at = $_20, updated_at = $_21, legal_basis = $_22;
surrealdb:driver:connection:execWithArgs map[string]interface {}{
surrealdb:driver:connection:execWithArgs "_1": "Lohnabrechnung",
surrealdb:driver:connection:execWithArgs "_10": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"Einholen der Bankdaten"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs "_11": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"Kontoinformationen"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs "_12": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"NAS", "Aktenschrank"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs "_13": "Lohnabrechnung",
surrealdb:driver:connection:execWithArgs "_14": "Beispiel der Lohnabrechnung",
surrealdb:driver:connection:execWithArgs "_15": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"Alex", "Daniel"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs "_16": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"Datendiebstahl", "Ausnutzung"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs "_17": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"Einholen der Bankdaten"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs "_18": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"Kontoinformationen"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs "_19": "Lohnabrechnung2",
surrealdb:driver:connection:execWithArgs "_2": "Beispiel der Lohnabrechnung",
surrealdb:driver:connection:execWithArgs "_20": "d'2025-02-16T02:10:20+01:00'",
surrealdb:driver:connection:execWithArgs "_21": "d'2025-02-16T02:10:20+01:00'",
surrealdb:driver:connection:execWithArgs "_22": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"GOB", "Wirtschaft"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs "_3": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"Alex", "Daniel"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs "_4": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"Datendiebstahl", "Ausnutzung"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs "_5": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"NAS", "Aktenschrank"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs "_6": "Lohnabrechnung2",
surrealdb:driver:connection:execWithArgs "_7": "d'2025-02-16T02:10:20+01:00'",
surrealdb:driver:connection:execWithArgs "_8": "d'2025-02-16T02:10:20+01:00'",
surrealdb:driver:connection:execWithArgs "_9": surrealtypes.ArrayOf[string]{
surrealdb:driver:connection:execWithArgs Values: {"GOB", "Wirtschaft"},
surrealdb:driver:connection:execWithArgs },
surrealdb:driver:connection:execWithArgs }
```

(I have some actually usable debug logging now...it helps a lot.)

The actual struct being passed is:

```
lohnabrechnung := Process{
ID: "Lohnabrechnung2",
Title: "Lohnabrechnung",
Description: "Beispiel der Lohnabrechnung",
CreatedAt: time.Now(),
UpdatedAt: time.Now(),
Responsible: st.ArrayOf[string]{Values: []string{"Alex", "Daniel"}},
LegalBasis: st.ArrayOf[string]{Values: []string{"GOB", "Wirtschaft"}},
Risks: st.ArrayOf[string]{Values: []string{"Datendiebstahl", "Ausnutzung"}},
Storage: st.ArrayOf[string]{Values: []string{"NAS", "Aktenschrank"}},
Tasks: st.ArrayOf[string]{Values: []string{"Einholen der Bankdaten"}},
AffectedData: st.ArrayOf[string]{Values: []string{"Kontoinformationen"}},
RelatedRisks: []Risk{ // <--- This does not get sent!
{Title: "Beispiel", Description: "Beschreibungszeug"},
{Title: "Beispiel 2", Description: "Beschreibungszeug 2"},
},
}
```

Is there any interface I can implement in my adapter to work with/around that?

Thank you and kind regards,

Ingwie