diff --git a/src/db_type.rs b/src/db_type.rs
new file mode 100644
index 0000000..3bbf526
--- /dev/null
+++ b/src/db_type.rs
@@ -0,0 +1,123 @@
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::{Data, DataStruct, DeriveInput, Fields, FieldsNamed, Path, parse_macro_input};
+
+pub fn db_type_impl(attr: TokenStream, item: TokenStream) -> TokenStream {
+    let derive_input = parse_macro_input!(item as DeriveInput);
+
+    // Get struct
+    let original_struct = if let Data::Struct(data_struct) = derive_input.data.clone() {
+        data_struct
+    } else {
+        return syn::Error::new_spanned(
+            derive_input.ident,
+            "#[db_type] can only be applied to structs",
+        )
+        .to_compile_error()
+        .into();
+    };
+
+    // Get fields
+    let fields = if let Fields::Named(fields) = &original_struct.fields {
+        fields.clone()
+    } else {
+        return syn::Error::new_spanned(
+            derive_input.ident,
+            "#[db_type] can only be applied to structs with named fields",
+        )
+        .to_compile_error()
+        .into();
+    };
+
+    let has_id_field = fields.named.iter().any(|field|
+        field.ident.as_ref()
+            .map_or(false, |field| field == "id")
+    );
+
+    // Filter out fields with the `#[omit_new]` attribute
+    let new_fields = fields.named.iter().filter(|field| {
+        !field
+            .attrs
+            .iter()
+            .any(|attr| attr.path().is_ident("omit_new"))
+    });
+
+    // Wrap back into FieldsNamed
+    let new_fields = Fields::Named(FieldsNamed {
+        brace_token: fields.brace_token,
+        named: new_fields.cloned().collect(),
+    });
+
+    // Create a new struct with the filtered fields
+    let new_struct = DataStruct {
+        fields: new_fields,
+        ..original_struct.clone()
+    };
+
+    // Create a new DeriveInput with the new struct, named "New<OriginalName>"
+    let new_name = format!("New{}", derive_input.ident.clone());
+    let new_derive_input = DeriveInput {
+        ident: syn::Ident::new(&new_name, derive_input.ident.span()),
+        data: Data::Struct(new_struct),
+        ..derive_input.clone()
+    };
+
+    // Remove `#[omit_new]` attributes from the original struct
+    let clean_original_fields = fields.named.iter().map(|field| {
+        let mut new_field = field.clone();
+        new_field
+            .attrs
+            .retain(|attr| !attr.path().is_ident("omit_new"));
+        new_field
+    });
+
+    // Wrap back into FieldsNamed
+    let clean_original_fields = Fields::Named(FieldsNamed {
+        brace_token: fields.brace_token,
+        named: clean_original_fields.collect(),
+    });
+
+    // Create a new struct with the cleaned fields
+    let clean_original_struct = DataStruct {
+        fields: clean_original_fields,
+        ..original_struct.clone()
+    };
+
+    // Create a new DeriveInput with the cleaned struct
+    let clean_derive_input = DeriveInput {
+        ident: derive_input.ident.clone(),
+        data: Data::Struct(clean_original_struct),
+        ..derive_input.clone()
+    };
+
+    // Get the table path from the attribute
+    let table_path = parse_macro_input!(attr as Path);
+
+    // Don't include the Identifiable derive for structs without an `id` field
+    let full_type_derives = if has_id_field {
+        quote! {
+            diesel::prelude::Queryable,
+            diesel::prelude::Selectable,
+            diesel::prelude::Identifiable
+        }
+    } else {
+        quote! {
+            diesel::prelude::Queryable,
+            diesel::prelude::Selectable
+        }
+    };
+
+    // Generate the expanded code
+    let expanded = quote! {
+        #[cfg_attr(feature = "ssr", derive(#full_type_derives))]
+        #[cfg_attr(feature = "ssr", diesel(check_for_backend(diesel::pg::Pg)))]
+        #[cfg_attr(feature = "ssr", diesel(table_name = #table_path))]
+        #clean_derive_input
+        #[cfg_attr(feature = "ssr", derive(diesel::prelude::Insertable))]
+        #[cfg_attr(feature = "ssr", diesel(check_for_backend(diesel::pg::Pg)))]
+        #[cfg_attr(feature = "ssr", diesel(table_name = #table_path))]
+        #new_derive_input
+    };
+
+    expanded.into()
+}
diff --git a/src/lib.rs b/src/lib.rs
index c572ebb..2a894d8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,124 +1,8 @@
 use proc_macro::TokenStream;
-use quote::quote;
-use syn::{Data, DataStruct, DeriveInput, Fields, FieldsNamed, Path, parse_macro_input};
+
+mod db_type;
 
 #[proc_macro_attribute]
 pub fn db_type(attr: TokenStream, item: TokenStream) -> TokenStream {
-    let derive_input = parse_macro_input!(item as DeriveInput);
-
-    // Get struct
-    let original_struct = if let Data::Struct(data_struct) = derive_input.data.clone() {
-        data_struct
-    } else {
-        return syn::Error::new_spanned(
-            derive_input.ident,
-            "#[db_type] can only be applied to structs",
-        )
-        .to_compile_error()
-        .into();
-    };
-
-    // Get fields
-    let fields = if let Fields::Named(fields) = &original_struct.fields {
-        fields.clone()
-    } else {
-        return syn::Error::new_spanned(
-            derive_input.ident,
-            "#[db_type] can only be applied to structs with named fields",
-        )
-        .to_compile_error()
-        .into();
-    };
-
-    let has_id_field = fields.named.iter().any(|field|
-        field.ident.as_ref()
-            .map_or(false, |field| field == "id")
-    );
-
-    // Filter out fields with the `#[omit_new]` attribute
-    let new_fields = fields.named.iter().filter(|field| {
-        !field
-            .attrs
-            .iter()
-            .any(|attr| attr.path().is_ident("omit_new"))
-    });
-
-    // Wrap back into FieldsNamed
-    let new_fields = Fields::Named(FieldsNamed {
-        brace_token: fields.brace_token,
-        named: new_fields.cloned().collect(),
-    });
-
-    // Create a new struct with the filtered fields
-    let new_struct = DataStruct {
-        fields: new_fields,
-        ..original_struct.clone()
-    };
-
-    // Create a new DeriveInput with the new struct, named "New<OriginalName>"
-    let new_name = format!("New{}", derive_input.ident.clone());
-    let new_derive_input = DeriveInput {
-        ident: syn::Ident::new(&new_name, derive_input.ident.span()),
-        data: Data::Struct(new_struct),
-        ..derive_input.clone()
-    };
-
-    // Remove `#[omit_new]` attributes from the original struct
-    let clean_original_fields = fields.named.iter().map(|field| {
-        let mut new_field = field.clone();
-        new_field
-            .attrs
-            .retain(|attr| !attr.path().is_ident("omit_new"));
-        new_field
-    });
-
-    // Wrap back into FieldsNamed
-    let clean_original_fields = Fields::Named(FieldsNamed {
-        brace_token: fields.brace_token,
-        named: clean_original_fields.collect(),
-    });
-
-    // Create a new struct with the cleaned fields
-    let clean_original_struct = DataStruct {
-        fields: clean_original_fields,
-        ..original_struct.clone()
-    };
-
-    // Create a new DeriveInput with the cleaned struct
-    let clean_derive_input = DeriveInput {
-        ident: derive_input.ident.clone(),
-        data: Data::Struct(clean_original_struct),
-        ..derive_input.clone()
-    };
-
-    // Get the table path from the attribute
-    let table_path = parse_macro_input!(attr as Path);
-
-    // Don't include the Identifiable derive for structs without an `id` field
-    let full_type_derives = if has_id_field {
-        quote! {
-            diesel::prelude::Queryable,
-            diesel::prelude::Selectable,
-            diesel::prelude::Identifiable
-        }
-    } else {
-        quote! {
-            diesel::prelude::Queryable,
-            diesel::prelude::Selectable
-        }
-    };
-
-    // Generate the expanded code
-    let expanded = quote! {
-        #[cfg_attr(feature = "ssr", derive(#full_type_derives))]
-        #[cfg_attr(feature = "ssr", diesel(check_for_backend(diesel::pg::Pg)))]
-        #[cfg_attr(feature = "ssr", diesel(table_name = #table_path))]
-        #clean_derive_input
-        #[cfg_attr(feature = "ssr", derive(diesel::prelude::Insertable))]
-        #[cfg_attr(feature = "ssr", diesel(check_for_backend(diesel::pg::Pg)))]
-        #[cfg_attr(feature = "ssr", diesel(table_name = #table_path))]
-        #new_derive_input
-    };
-
-    expanded.into()
+    db_type::db_type_impl(attr, item)
 }