Function upsert_relationship 

pub fn upsert_relationship(
    conn: &Connection,
    namespace: &str,
    source_id: i64,
    target_id: i64,
    rel: &NewRelationship,
) -> Result<i64, AppError>

Upserts a typed relationship between two entity ids.

Conflicts on (source_id, target_id, relation) refresh weight and preserve a non-null description. Returns the rowid of the stored row.

Errors

Returns Err(AppError::Database) on any rusqlite failure.