I have this common use case where I join two tables and I want to deserialize a row in

Joint row deserialization into structs about libsql HOT 1 OPEN

aminya commented on June 1, 2024 1

Joint row deserialization into structs

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Comments (1)

sveltespot commented on June 1, 2024 1

We do face the same issues. Currently, our work around for this is to use #[serde(alias = 'some_unique_name')] for each of the fields of the struct. So considering your use case, it will look something like:

#[derive(Debug, Clone, Eq, PartialEq, Hash, Serialize, Deserialize, Default)]
pub struct User {
  #[serde(alias='user_table_id')]
  pub id: i32,
  #[serde(alias='user_table_date')]
  pub date: DateTime<Utc>,
  #[serde(alias='user_table_group_id')]
  pub group_id: i32,
}

#[derive(Debug, Clone, Eq, PartialEq, Hash, Serialize, Deserialize, Default)]
pub struct Group {
  #[serde(alias='group_table_id')]
  pub id: i32,
  #[serde(alias='group_table_name')]
  pub name: String,
}

And then modify your query to include those names, like so:

let rows = db_conn
   .query(
     "SELECT users.id as user_table_id,
           users.date as user_table_date,
           users.group_id as user_table_group_id,
           groups.id as group_table_id,
           groups.name as group_table_name
         FROM users
         JOIN groups ON users.group_id = groups.id
         WHERE users.user_id = ?1 LIMIT ?2
   ",
     params![user_id.clone(), 10],
   )
   .await?;

while let Some(row) = rows.next().await? {
   let user = from_row<User>(&row)?;
   let group = from_row<Group>(&row)?;
}

Although this seems like a lot of work, but since the query is mostly generated programmatically, this is a fair bit easier to work with. But I totally agree with you that if there was some solution to this directly from libsql, it would be a huge help.

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