Queries attribute macros

Edgedb-query-derive crate provide 5 macro attributes that represent a edgeDB query:

• #[insert_query]
• #[select_query]
• #[update_query]
• #[delete_query]
• #[query]
• #[file_query]

Queries attributes (except #[file_query] ) take three arguments 👇

When a struct is decorated with one of those queries macro attributes, several trait implementations are created for this one:

• ToEdgeQl
• ToEdgeValue
• ToEdgeQuery
• ToEdgeScalar
• ToString

The following example shows how to get a parameterized query from a struct decorated with a query macro attribute ( #[insert_query] for example) :

Consider the following struct 👇:

    #[insert_query(module="humans", table="Person")]
    pub struct InsertPerson {
        pub name: String,
        pub age: i8
    }

To get a parameterized query from this struct, we can write the following code:

    #[tokio::main]
    fn main() -> Result<()>{
        let insert_person = InsertPerson {
            name: "John".to_string(),
            age: 20
        };
        
        let edge_query: EdgeQuery = insert_person.to_edge_query();
    
    }

to_edge_query() ( from ToEdgeQuery trait ) method returns a EdgeQuery struct that contains the query string and the query parameters.

The query's cardinality (Cardinality::Many by default) can also be set while getting the query by calling to_edge_query_with_cardinality() method instead of to_edge_query().

    let edge_query: EdgeQuery = insert_person.to_edge_query_with_cardinality(Cardinality::One);

With the got query, we can now execute request using edgedb-client like this:

     if let EdgeQuery{ query, args: Some(params), .. } = edge_query {
         let result: BasicResult = client.query_required_single(query.as_str(), params).await?;
     }