diff --git a/src/database/database_view.rs b/src/database/database_view.rs
index 1db5047b0..576fd1f9b 100644
--- a/src/database/database_view.rs
+++ b/src/database/database_view.rs
@@ -7,7 +7,9 @@ use serde::de::DeserializeOwned;
 
 use crate::database::{retrieve_data_schema, DocumentKey, DocumentKeyAttr};
 use crate::database::deserializer::Deserializer;
+use crate::rank::criterion::Criterion;
 use crate::database::schema::Schema;
+use crate::rank::QueryBuilder;
 use crate::DocumentId;
 
 pub struct DatabaseView<'a> {
@@ -21,14 +23,26 @@ impl<'a> DatabaseView<'a> {
         Ok(DatabaseView { snapshot, schema })
     }
 
+    pub fn schema(&self) -> &Schema {
+        &self.schema
+    }
+
     pub fn into_snapshot(self) -> Snapshot<&'a DB> {
         self.snapshot
     }
 
+    pub fn snapshot(&self) -> &Snapshot<&'a DB> {
+        &self.snapshot
+    }
+
     pub fn get(&self, key: &[u8]) -> Result<Option<DBVector>, Box<Error>> {
         Ok(self.snapshot.get(key)?)
     }
 
+    pub fn query_builder(&self) -> Result<QueryBuilder<Box<dyn Criterion>>, Box<Error>> {
+        QueryBuilder::new(self)
+    }
+
     // TODO create an enum error type
     pub fn retrieve_document<D>(&self, id: DocumentId) -> Result<D, Box<Error>>
     where D: DeserializeOwned
diff --git a/src/database/mod.rs b/src/database/mod.rs
index db864fa37..c347b11ce 100644
--- a/src/database/mod.rs
+++ b/src/database/mod.rs
@@ -8,7 +8,7 @@ use rocksdb::{DB, DBVector, MergeOperands, SeekKey};
 use rocksdb::rocksdb::{Writable, Snapshot};
 
 pub use self::document_key::{DocumentKey, DocumentKeyAttr};
-pub use self::database_view::DatabaseView;
+pub use self::database_view::{DatabaseView, DocumentIter};
 use self::blob::positive::PositiveBlob;
 use self::update::Update;
 use self::schema::Schema;
@@ -126,7 +126,7 @@ impl fmt::Debug for Database {
         let mut iter = self.0.iter();
         iter.seek(SeekKey::Start);
         let mut first = true;
-        for (key, value) in &mut iter {
+        for (key, _value) in &mut iter {
             if !first { write!(f, ", ")?; }
             first = false;
             let key = String::from_utf8_lossy(&key);
diff --git a/src/database/update/positive/unordered_builder.rs b/src/database/update/positive/unordered_builder.rs
index b44455360..7a2139c98 100644
--- a/src/database/update/positive/unordered_builder.rs
+++ b/src/database/update/positive/unordered_builder.rs
@@ -1,3 +1,5 @@
+#![allow(unused)]
+
 use std::collections::BTreeMap;
 use std::error::Error;
 use std::io::Write;
diff --git a/src/database/update/positive/update.rs b/src/database/update/positive/update.rs
index 8924073aa..4b57405ab 100644
--- a/src/database/update/positive/update.rs
+++ b/src/database/update/positive/update.rs
@@ -107,7 +107,7 @@ struct Serializer<'a, B> {
 macro_rules! forward_to_unserializable_type {
     ($($ty:ident => $se_method:ident,)*) => {
         $(
-            fn $se_method(self, v: $ty) -> Result<Self::Ok, Self::Error> {
+            fn $se_method(self, _v: $ty) -> Result<Self::Ok, Self::Error> {
                 Err(SerializerError::UnserializableType { name: "$ty" })
             }
         )*
@@ -145,11 +145,11 @@ where B: TokenizerBuilder
         f64 => serialize_f64,
     }
 
-    fn serialize_str(self, v: &str) -> Result<Self::Ok, Self::Error> {
+    fn serialize_str(self, _v: &str) -> Result<Self::Ok, Self::Error> {
         Err(SerializerError::UnserializableType { name: "str" })
     }
 
-    fn serialize_bytes(self, v: &[u8]) -> Result<Self::Ok, Self::Error> {
+    fn serialize_bytes(self, _v: &[u8]) -> Result<Self::Ok, Self::Error> {
         Err(SerializerError::UnserializableType { name: "&[u8]" })
     }
 
@@ -375,7 +375,7 @@ where B: TokenizerBuilder
         Ok(())
     }
 
-    fn serialize_bytes(self, v: &[u8]) -> Result<Self::Ok, Self::Error> {
+    fn serialize_bytes(self, _v: &[u8]) -> Result<Self::Ok, Self::Error> {
         Err(SerializerError::UnserializableType { name: "&[u8]" })
     }
 
diff --git a/src/rank/criterion/exact.rs b/src/rank/criterion/exact.rs
index 2cdb9c0dd..9ea59eae3 100644
--- a/src/rank/criterion/exact.rs
+++ b/src/rank/criterion/exact.rs
@@ -1,8 +1,11 @@
 use std::cmp::Ordering;
+
 use group_by::GroupBy;
-use crate::Match;
+
 use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
+use crate::database::DatabaseView;
+use crate::Match;
 
 #[inline]
 fn contains_exact(matches: &[Match]) -> bool {
@@ -18,7 +21,7 @@ fn number_exact_matches(matches: &[Match]) -> usize {
 pub struct Exact;
 
 impl Criterion for Exact {
-    fn evaluate(&self, lhs: &Document, rhs: &Document) -> Ordering {
+    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView) -> Ordering {
         let lhs = number_exact_matches(&lhs.matches);
         let rhs = number_exact_matches(&rhs.matches);
 
diff --git a/src/rank/criterion/mod.rs b/src/rank/criterion/mod.rs
index bf54e9863..a4590ae90 100644
--- a/src/rank/criterion/mod.rs
+++ b/src/rank/criterion/mod.rs
@@ -7,6 +7,8 @@ mod exact;
 
 use std::vec;
 use std::cmp::Ordering;
+
+use crate::database::DatabaseView;
 use crate::rank::Document;
 
 pub use self::{
@@ -20,31 +22,31 @@ pub use self::{
 
 pub trait Criterion {
     #[inline]
-    fn evaluate(&self, lhs: &Document, rhs: &Document) -> Ordering;
+    fn evaluate(&self, lhs: &Document, rhs: &Document, view: &DatabaseView) -> Ordering;
 
     #[inline]
-    fn eq(&self, lhs: &Document, rhs: &Document) -> bool {
-        self.evaluate(lhs, rhs) == Ordering::Equal
+    fn eq(&self, lhs: &Document, rhs: &Document, view: &DatabaseView) -> bool {
+        self.evaluate(lhs, rhs, view) == Ordering::Equal
     }
 }
 
 impl<'a, T: Criterion + ?Sized> Criterion for &'a T {
-    fn evaluate(&self, lhs: &Document, rhs: &Document) -> Ordering {
-        (**self).evaluate(lhs, rhs)
+    fn evaluate(&self, lhs: &Document, rhs: &Document, view: &DatabaseView) -> Ordering {
+        (**self).evaluate(lhs, rhs, view)
     }
 
-    fn eq(&self, lhs: &Document, rhs: &Document) -> bool {
-        (**self).eq(lhs, rhs)
+    fn eq(&self, lhs: &Document, rhs: &Document, view: &DatabaseView) -> bool {
+        (**self).eq(lhs, rhs, view)
     }
 }
 
 impl<T: Criterion + ?Sized> Criterion for Box<T> {
-    fn evaluate(&self, lhs: &Document, rhs: &Document) -> Ordering {
-        (**self).evaluate(lhs, rhs)
+    fn evaluate(&self, lhs: &Document, rhs: &Document, view: &DatabaseView) -> Ordering {
+        (**self).evaluate(lhs, rhs, view)
     }
 
-    fn eq(&self, lhs: &Document, rhs: &Document) -> bool {
-        (**self).eq(lhs, rhs)
+    fn eq(&self, lhs: &Document, rhs: &Document, view: &DatabaseView) -> bool {
+        (**self).eq(lhs, rhs, view)
     }
 }
 
@@ -52,7 +54,7 @@ impl<T: Criterion + ?Sized> Criterion for Box<T> {
 pub struct DocumentId;
 
 impl Criterion for DocumentId {
-    fn evaluate(&self, lhs: &Document, rhs: &Document) -> Ordering {
+    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView) -> Ordering {
         lhs.id.cmp(&rhs.id)
     }
 }
diff --git a/src/rank/criterion/number_of_words.rs b/src/rank/criterion/number_of_words.rs
index 902e49fc0..b20586f39 100644
--- a/src/rank/criterion/number_of_words.rs
+++ b/src/rank/criterion/number_of_words.rs
@@ -1,8 +1,11 @@
 use std::cmp::Ordering;
+
 use group_by::GroupBy;
-use crate::Match;
+
 use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
+use crate::database::DatabaseView;
+use crate::Match;
 
 #[inline]
 fn number_of_query_words(matches: &[Match]) -> usize {
@@ -13,7 +16,7 @@ fn number_of_query_words(matches: &[Match]) -> usize {
 pub struct NumberOfWords;
 
 impl Criterion for NumberOfWords {
-    fn evaluate(&self, lhs: &Document, rhs: &Document) -> Ordering {
+    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView) -> Ordering {
         let lhs = number_of_query_words(&lhs.matches);
         let rhs = number_of_query_words(&rhs.matches);
 
diff --git a/src/rank/criterion/sum_of_typos.rs b/src/rank/criterion/sum_of_typos.rs
index 911a6c67f..5cbd4bac1 100644
--- a/src/rank/criterion/sum_of_typos.rs
+++ b/src/rank/criterion/sum_of_typos.rs
@@ -1,8 +1,11 @@
 use std::cmp::Ordering;
+
 use group_by::GroupBy;
-use crate::Match;
+
 use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
+use crate::database::DatabaseView;
+use crate::Match;
 
 #[inline]
 fn sum_matches_typos(matches: &[Match]) -> i8 {
@@ -23,7 +26,7 @@ fn sum_matches_typos(matches: &[Match]) -> i8 {
 pub struct SumOfTypos;
 
 impl Criterion for SumOfTypos {
-    fn evaluate(&self, lhs: &Document, rhs: &Document) -> Ordering {
+    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView) -> Ordering {
         let lhs = sum_matches_typos(&lhs.matches);
         let rhs = sum_matches_typos(&rhs.matches);
 
@@ -64,7 +67,9 @@ mod tests {
             }
         };
 
-        assert_eq!(SumOfTypos.evaluate(&doc0, &doc1), Ordering::Less);
+        let lhs = sum_matches_typos(&doc0.matches);
+        let rhs = sum_matches_typos(&doc1.matches);
+        assert_eq!(lhs.cmp(&rhs), Ordering::Less);
     }
 
     // typing: "bouton manchette"
@@ -94,7 +99,9 @@ mod tests {
             }
         };
 
-        assert_eq!(SumOfTypos.evaluate(&doc0, &doc1), Ordering::Less);
+        let lhs = sum_matches_typos(&doc0.matches);
+        let rhs = sum_matches_typos(&doc1.matches);
+        assert_eq!(lhs.cmp(&rhs), Ordering::Less);
     }
 
     // typing: "bouton manchztte"
@@ -124,6 +131,8 @@ mod tests {
             }
         };
 
-        assert_eq!(SumOfTypos.evaluate(&doc0, &doc1), Ordering::Equal);
+        let lhs = sum_matches_typos(&doc0.matches);
+        let rhs = sum_matches_typos(&doc1.matches);
+        assert_eq!(lhs.cmp(&rhs), Ordering::Equal);
     }
 }
diff --git a/src/rank/criterion/sum_of_words_attribute.rs b/src/rank/criterion/sum_of_words_attribute.rs
index 95629e2b5..d373dedef 100644
--- a/src/rank/criterion/sum_of_words_attribute.rs
+++ b/src/rank/criterion/sum_of_words_attribute.rs
@@ -1,8 +1,11 @@
 use std::cmp::Ordering;
+
 use group_by::GroupBy;
-use crate::Match;
+
+use crate::database::DatabaseView;
 use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
+use crate::Match;
 
 #[inline]
 fn sum_matches_attributes(matches: &[Match]) -> u8 {
@@ -17,7 +20,7 @@ fn sum_matches_attributes(matches: &[Match]) -> u8 {
 pub struct SumOfWordsAttribute;
 
 impl Criterion for SumOfWordsAttribute {
-    fn evaluate(&self, lhs: &Document, rhs: &Document) -> Ordering {
+    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView) -> Ordering {
         let lhs = sum_matches_attributes(&lhs.matches);
         let rhs = sum_matches_attributes(&rhs.matches);
 
diff --git a/src/rank/criterion/sum_of_words_position.rs b/src/rank/criterion/sum_of_words_position.rs
index 5a230fed2..cd41d5b72 100644
--- a/src/rank/criterion/sum_of_words_position.rs
+++ b/src/rank/criterion/sum_of_words_position.rs
@@ -1,8 +1,11 @@
 use std::cmp::Ordering;
+
 use group_by::GroupBy;
-use crate::Match;
+
+use crate::database::DatabaseView;
 use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
+use crate::Match;
 
 #[inline]
 fn sum_matches_attribute_index(matches: &[Match]) -> u32 {
@@ -17,7 +20,7 @@ fn sum_matches_attribute_index(matches: &[Match]) -> u32 {
 pub struct SumOfWordsPosition;
 
 impl Criterion for SumOfWordsPosition {
-    fn evaluate(&self, lhs: &Document, rhs: &Document) -> Ordering {
+    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView) -> Ordering {
         let lhs = sum_matches_attribute_index(&lhs.matches);
         let rhs = sum_matches_attribute_index(&rhs.matches);
 
diff --git a/src/rank/criterion/words_proximity.rs b/src/rank/criterion/words_proximity.rs
index 8c2344595..abbd0e99f 100644
--- a/src/rank/criterion/words_proximity.rs
+++ b/src/rank/criterion/words_proximity.rs
@@ -1,8 +1,11 @@
 use std::cmp::{self, Ordering};
+
 use group_by::GroupBy;
-use crate::Match;
+
 use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
+use crate::database::DatabaseView;
+use crate::Match;
 
 const MAX_DISTANCE: u32 = 8;
 
@@ -47,7 +50,7 @@ fn matches_proximity(matches: &[Match]) -> u32 {
 pub struct WordsProximity;
 
 impl Criterion for WordsProximity {
-    fn evaluate(&self, lhs: &Document, rhs: &Document) -> Ordering {
+    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView) -> Ordering {
         let lhs = matches_proximity(&lhs.matches);
         let rhs = matches_proximity(&rhs.matches);
 
diff --git a/src/rank/query_builder.rs b/src/rank/query_builder.rs
index 34ca4f212..6dc13eb9b 100644
--- a/src/rank/query_builder.rs
+++ b/src/rank/query_builder.rs
@@ -1,9 +1,8 @@
-use std::ops::{Deref, Range};
-use std::{mem, vec, str};
 use std::error::Error;
 use std::hash::Hash;
+use std::ops::Range;
+use std::{mem, vec, str};
 
-use ::rocksdb::rocksdb::{DB, Snapshot};
 use group_by::GroupByMut;
 use hashbrown::HashMap;
 use fst::Streamer;
@@ -13,16 +12,10 @@ use crate::rank::criterion::{self, Criterion};
 use crate::rank::distinct_map::DistinctMap;
 use crate::database::retrieve_data_index;
 use crate::database::blob::PositiveBlob;
+use crate::database::DatabaseView;
 use crate::{Match, DocumentId};
 use crate::rank::Document;
 
-fn clamp_range<T: Copy + Ord>(range: Range<T>, big: Range<T>) -> Range<T> {
-    Range {
-        start: range.start.min(big.end).max(big.start),
-        end: range.end.min(big.end).max(big.start),
-    }
-}
-
 fn split_whitespace_automatons(query: &str) -> Vec<DfaExt> {
     let mut automatons = Vec::new();
     for query in query.split_whitespace().map(str::to_lowercase) {
@@ -32,24 +25,22 @@ fn split_whitespace_automatons(query: &str) -> Vec<DfaExt> {
     automatons
 }
 
-pub struct QueryBuilder<T: Deref<Target=DB>, C> {
-    snapshot: Snapshot<T>,
+pub struct QueryBuilder<'a, C> {
+    view: &'a DatabaseView<'a>,
     blob: PositiveBlob,
     criteria: Vec<C>,
 }
 
-impl<T: Deref<Target=DB>> QueryBuilder<T, Box<dyn Criterion>> {
-    pub fn new(snapshot: Snapshot<T>) -> Result<Self, Box<Error>> {
-        QueryBuilder::with_criteria(snapshot, criterion::default())
+impl<'a> QueryBuilder<'a, Box<dyn Criterion>> {
+    pub fn new(view: &'a DatabaseView<'a>) -> Result<Self, Box<Error>> {
+        QueryBuilder::with_criteria(view, criterion::default())
     }
 }
 
-impl<T, C> QueryBuilder<T, C>
-where T: Deref<Target=DB>,
-{
-    pub fn with_criteria(snapshot: Snapshot<T>, criteria: Vec<C>) -> Result<Self, Box<Error>> {
-        let blob = retrieve_data_index(&snapshot)?;
-        Ok(QueryBuilder { snapshot, blob, criteria })
+impl<'a, C> QueryBuilder<'a, C> {
+    pub fn with_criteria(view: &'a DatabaseView<'a>, criteria: Vec<C>) -> Result<Self, Box<Error>> {
+        let blob = retrieve_data_index(view.snapshot())?;
+        Ok(QueryBuilder { view, blob, criteria })
     }
 
     pub fn criteria(&mut self, criteria: Vec<C>) -> &mut Self {
@@ -57,7 +48,7 @@ where T: Deref<Target=DB>,
         self
     }
 
-    pub fn with_distinct<F>(self, function: F, size: usize) -> DistinctQueryBuilder<T, F, C> {
+    pub fn with_distinct<F>(self, function: F, size: usize) -> DistinctQueryBuilder<'a, F, C> {
         DistinctQueryBuilder {
             inner: self,
             function: function,
@@ -105,23 +96,21 @@ where T: Deref<Target=DB>,
     }
 }
 
-impl<T, C> QueryBuilder<T, C>
-where T: Deref<Target=DB>,
-      C: Criterion,
+impl<'a, C> QueryBuilder<'a, C>
+where C: Criterion
 {
     pub fn query(&self, query: &str, limit: usize) -> Vec<Document> {
         let mut documents = self.query_all(query);
         let mut groups = vec![documents.as_mut_slice()];
+        let view = &self.view;
 
         'group: for criterion in &self.criteria {
             let tmp_groups = mem::replace(&mut groups, Vec::new());
             let mut computed = 0;
 
             for group in tmp_groups {
-
-                group.sort_unstable_by(|a, b| criterion.evaluate(a, b));
-                for group in GroupByMut::new(group, |a, b| criterion.eq(a, b)) {
-
+                group.sort_unstable_by(|a, b| criterion.evaluate(a, b, view));
+                for group in GroupByMut::new(group, |a, b| criterion.eq(a, b, view)) {
                     computed += group.len();
                     groups.push(group);
                     if computed >= limit { break 'group }
@@ -134,41 +123,38 @@ where T: Deref<Target=DB>,
     }
 }
 
-pub struct DistinctQueryBuilder<T: Deref<Target=DB>, F, C> {
-    inner: QueryBuilder<T, C>,
+pub struct DistinctQueryBuilder<'a, F, C> {
+    inner: QueryBuilder<'a, C>,
     function: F,
     size: usize,
 }
 
-pub struct DocDatabase;
-
-impl<T: Deref<Target=DB>, F, K, C> DistinctQueryBuilder<T, F, C>
-where T: Deref<Target=DB>,
-      F: Fn(DocumentId, &DocDatabase) -> Option<K>,
+impl<'a, F, K, C> DistinctQueryBuilder<'a, F, C>
+where F: Fn(DocumentId, &DatabaseView) -> Option<K>,
       K: Hash + Eq,
       C: Criterion,
 {
     pub fn query(&self, query: &str, range: Range<usize>) -> Vec<Document> {
         let mut documents = self.inner.query_all(query);
         let mut groups = vec![documents.as_mut_slice()];
+        let view = &self.inner.view;
 
         for criterion in &self.inner.criteria {
             let tmp_groups = mem::replace(&mut groups, Vec::new());
 
             for group in tmp_groups {
-                group.sort_unstable_by(|a, b| criterion.evaluate(a, b));
-                for group in GroupByMut::new(group, |a, b| criterion.eq(a, b)) {
+                group.sort_unstable_by(|a, b| criterion.evaluate(a, b, view));
+                for group in GroupByMut::new(group, |a, b| criterion.eq(a, b, view)) {
                     groups.push(group);
                 }
             }
         }
 
-        let doc_database = DocDatabase;
         let mut out_documents = Vec::with_capacity(range.len());
         let mut seen = DistinctMap::new(self.size);
 
         for document in documents {
-            let accepted = match (self.function)(document.id, &doc_database) {
+            let accepted = match (self.function)(document.id, &self.inner.view) {
                 Some(key) => seen.digest(key),
                 None => seen.accept_without_key(),
             };