Add method to create Models from only required fields

sea-orm-macros/src/derives/model_ex.rs

@@ -50,13 +50,19 @@ pub fn expand_sea_orm_model(input: ItemStruct, compact: bool) -> syn::Result<Tok
     };
 
     let mut model_fields = Vec::new();
+    let mut required_model_fields = Vec::new();
 
     for field in all_fields.iter_mut() {
         let field_type = &field.ty;
         let field_type = quote! { #field_type }
             .to_string() // e.g.: "Option < String >"
             .replace(' ', ""); // Remove spaces
-
+        if !(field_type.starts_with("Option<")
+            || field_type.starts_with("HasMany<")
+            || field_type.starts_with("HasOne<"))
+        {
+            required_model_fields.push(field.clone());
+        }
         if is_compound_field(&field_type) {
             let entity_path = extract_compound_entity(&field_type);
             if field_type.starts_with("Option<") || field_type.starts_with("HasOne<") {
@@ -69,6 +75,31 @@ pub fn expand_sea_orm_model(input: ItemStruct, compact: bool) -> syn::Result<Tok
         }
     }
 
+    let non_required_model_field_names = model_fields
+        .iter()
+        .filter(|item| !required_model_fields.contains(item))
+        .map(|item| &item.ident)
+        .collect::<Vec<_>>();
+
+    let required_field_names = required_model_fields
+        .iter()
+        .map(|item| &item.ident)
+        .collect::<Vec<_>>();
+    let required_field_types = required_model_fields
+        .iter()
+        .map(|item| &item.ty)
+        .collect::<Vec<_>>();
+    let from_required_fields = quote! {
+        impl #model_ex {
+            pub fn model_from_required(#(#required_field_names: #required_field_types),*) -> #model {
+                #model {
+                    #(#required_field_names),*,
+                    #(#non_required_model_field_names : None),*
+                }
+            }
+        }
+    };
+
     Ok(quote! {
         #(#model_attrs)*
         #[sea_orm(model_ex)]
@@ -79,6 +110,7 @@ pub fn expand_sea_orm_model(input: ItemStruct, compact: bool) -> syn::Result<Tok
         #(#model_ex_attrs)*
         #compact_model
         #vis struct #model_ex #all_fields
+        #from_required_fields
     })
 }
 
@@ -785,6 +817,8 @@ fn to_upper_camel_case(i: &Ident) -> Ident {
 #[cfg(test)]
 mod test {
     use super::format_tuple;
+    use crate::{DbErr, entity::*, tests_cfg::*};
+    use pretty_assertions::assert_eq;
 
     #[test]
     fn test_format_tuple() {
@@ -799,4 +833,16 @@ mod test {
             "(super::Column::A, super::Column::B)"
         );
     }
+
+    #[test]
+    fn test_new_from_required() {
+        assert_eq!(
+            fruit::ModelEx::model_from_required(1, "Example Fruit"),
+            fruit::Model {
+                id: 1,
+                name: "Example Fruit",
+                cake_id: None,
+            }
+        );
+    }
 }