feat: Nullable enums

internal/codegen/golang/imports.go

@@ -264,6 +264,7 @@ func (i *importer) modelImports() fileImports {
 
 	if len(i.Enums) > 0 {
 		std["fmt"] = struct{}{}
+		std["database/sql/driver"] = struct{}{}
 	}
 
 	return sortedImports(std, pkg)

internal/codegen/golang/postgresql_type.go

@@ -279,11 +279,15 @@ func postgresType(req *plugin.CodeGenRequest, col *plugin.Column) string {
 			}
 
 			for _, enum := range schema.Enums {
+				nullPrefix := ""
+				if !notNull {
+					nullPrefix = "Null"
+				}
 				if rel.Name == enum.Name && rel.Schema == schema.Name {
 					if schema.Name == req.Catalog.DefaultSchema {
-						return StructName(enum.Name, req.Settings)
+						return nullPrefix + StructName(enum.Name, req.Settings)
 					}
-					return StructName(schema.Name+"_"+enum.Name, req.Settings)
+					return nullPrefix + StructName(schema.Name+"_"+enum.Name, req.Settings)
 				}
 			}
 

internal/codegen/golang/templates/template.tmpl

@@ -86,6 +86,36 @@ func (e *{{.Name}}) Scan(src interface{}) error {
 	}
 	return nil
 }
+
+// Null{{.Name}} is the nullable version of {{.Name}}.
+type Null{{.Name}} struct {
+	{{.Name}} {{.Name}}
+	Valid bool
+}
+
+func (e *Null{{.Name}}) Scan(src interface{}) error {
+	if src == nil {
+		e.Valid = false
+		return nil
+	}
+	switch s := src.(type) {
+	case []byte:
+		e.{{.Name}} = {{.Name}}(s)
+	case string:
+		e.{{.Name}} = {{.Name}}(s)
+	default:
+		return fmt.Errorf("unsupported scan type for Null{{.Name}}: %T", src)
+	}
+	e.Valid = len(e.{{.Name}}) > 0
+	return nil
+}
+
+func (e *Null{{.Name}}) Value() (driver.Value, error) {
+	if !e.Valid {
+		return nil, nil
+	}
+	return string(e.{{.Name}}), nil
+}
 {{end}}
 
 {{range .Structs}}