diff --git a/README.md b/README.md
index 0e98be6..1a8cbc2 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 mongod is a rust crate for a model based database on top of MongoDB.
 
 ## Usage
-`mongod` allows you to use structs as `models` with data. it is build upon a MongoDB database. You need to pass a Connection URI for the database to use via the `$DB_URI` environment variable.
+`mongod` allows you to use structs as `models` with data. it is build upon a MongoDB database. You need to pass a Connection URI for the database to use via the `$DB_URI` environment variable. The database to use can be configured via `$DB` environment variable.
 
 ### Models
 You can derive the `Model` and `Referencable` traits for your struct. This will provide you with functions like `insert()`, `delete()`, `update()`, `get()`, etc for your struct. Additionally you have to manually implement the `Validate` trait which ensures a consistent valid state of your struct in order to never insert invalid data into the database.
diff --git a/src/lib.rs b/src/lib.rs
index 3337ba6..66d6136 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -20,7 +20,7 @@ macro_rules! get_mongo {
 #[macro_export]
 macro_rules! col {
     ($db:expr, $col:expr) => {
-        $db.database("owl")
+        $db.database(&std::env::var("DB").unwrap())
             .collection::<mongodb::bson::Document>($col)
     };
 }
diff --git a/src/model/mod.rs b/src/model/mod.rs
index f0b22c7..ed2239f 100644
--- a/src/model/mod.rs
+++ b/src/model/mod.rs
@@ -87,17 +87,20 @@ pub trait Model:
     #[must_use]
     fn get_partial(
         id: &str,
-        part: &serde_json::Value,
+        mut part: serde_json::Value,
     ) -> impl std::future::Future<Output = Option<Self::Partial>> {
         async move {
             let db = get_mongo!();
             let collection = col!(db, Self::collection_name());
+
+            part.as_object_mut()?.insert("_id".into(), 1.into());
+
             let doc = collection
                 .find_one(
                     id_of!(id),
                     Some(
                         FindOneOptions::builder()
-                            .projection(Some(mongodb::bson::to_document(part).unwrap()))
+                            .projection(Some(mongodb::bson::to_document(&part).unwrap()))
                             .build(),
                     ),
                 )
@@ -111,17 +114,20 @@ pub trait Model:
     #[must_use]
     fn find_one_partial(
         filter: mongodb::bson::Document,
-        part: &serde_json::Value,
+        mut part: serde_json::Value,
     ) -> impl std::future::Future<Output = Option<Self::Partial>> {
         async move {
             let db = get_mongo!();
             let collection = col!(db, Self::collection_name());
+
+            part.as_object_mut()?.insert("_id".into(), 1.into());
+
             let doc = collection
                 .find_one(
                     filter,
                     Some(
                         FindOneOptions::builder()
-                            .projection(Some(mongodb::bson::to_document(part).unwrap()))
+                            .projection(Some(mongodb::bson::to_document(&part).unwrap()))
                             .build(),
                     ),
                 )
@@ -164,17 +170,20 @@ pub trait Model:
     #[must_use]
     fn find_partial(
         filter: mongodb::bson::Document,
-        part: &serde_json::Value,
+        mut part: serde_json::Value,
     ) -> impl std::future::Future<Output = Option<Vec<Self>>> {
         async move {
             let db = get_mongo!();
             let collection = col!(db, Self::collection_name());
+
+            part.as_object_mut()?.insert("_id".into(), 1.into());
+
             let mut results = collection
                 .find(
                     filter,
                     Some(
                         FindOptions::builder()
-                            .projection(Some(mongodb::bson::to_document(part).unwrap()))
+                            .projection(Some(mongodb::bson::to_document(&part).unwrap()))
                             .build(),
                     ),
                 )