Provide scanonly or insertonly

[bgdnxt]

I have a generated column in PG table, and applied scanonly tag in model, here is the example code:

# the schema
CREATE TABLE IF NOT EXISTS users (
    id bigint PRIMARY KEY DEFAULT snow_gen_id(),
    created_at timestamptz DEFAULT CURRENT_TIMESTAMP,
    updated_at timestamptz DEFAULT CURRENT_TIMESTAMP,
    object_id varchar(128) GENERATED ALWAYS AS ('USR' || cast(id as varchar)) STORED
}

# the model
type User struct {
	ID        int64     `json:"id,string"`
	CreatedAt time.Time `json:"createdAt"`
	UpdatedAt time.Time `json:"updatedAt"`
	ObjectID  string    `json:"objectId" bun:",scanonly"`
}

# the selection

user := &User{}
err := bundb.NewSelect().Model(user).Where("id = ?", id).Scan(context.background())

# the debug print sql

SELECT "user"."id", "user"."created_at", "user"."updated_at" FROM "users" AS "user" ORDER BY "id" ASC

I would expect the object_id appear in the query, but it doesn't.

[vmihailenco]

scanonly is for scanning results, for example, SELECT t.a + t.b AS sum. It can be added without complicating the code so that's why we have it.

For now, you can split your model like this:

type UserData struct {
	bun.BaseModel `bun:"users"`

	ID        int64     `json:"id,string"`
	CreatedAt time.Time `json:"createdAt"`
	UpdatedAt time.Time `json:"updatedAt"`
}

type User struct {
	UserData `bun:",inherit"`
	ObjectID  string    `json:"objectId"`
}

Not sure if we need selectonly or insertonly to support this more elegantly. Time will tell.

[bgdnxt]

Got it, so I'm misleading for the scanonly. looking forward for the enhancement.

[imraan-go]

inherit

What does this "inherit" do? It is not documented anywhere!

[vmihailenco]

That's an alias for ,extend - I've documented it here.

[imraan-go]

@vmihailenco Can we have a readonly and insertonly tag? readonly will be so helpful.

[vmihailenco]

I did not mean to close this.

@imraan-go could you describe your use case so I have an idea how this will be used?

[imraan-go]

"id" uuid NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY

@vmihailenco for this type of schenario readonly will be useful and clear. I want database to autogenerate the uuid. Currently the way to implement this is to use bun tag autoincrement to insert default in the sql query. But the autoincrement tag is really confusing in this case and feels like a hack. readonly tag will make it more clear that the column will be ommitted in insert or update. readonly will behave more like a ExcludeColumn on table level instead of query level.

[vmihailenco]

@imraan-go it should be nullzero not autoincrement

type Model struct {
    ID UUD `bun:",pk,nullzero"`
}

[codeliger]

How can we select computed columns without insert/updating them? There seems to be no solution currently.

[dionb]

My immediate usecase for insertonly would be for CreatedAt and CreatedBy fields. To ensure that they are only written to on creation of a resource, and to protect against devs making mistakes.

[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. If there is no update within the next 7 days, this issue will be closed.