diff --git a/cozo-core/benches/pokec.rs b/cozo-core/benches/pokec.rs
index 04bbc24b..461b3a71 100644
--- a/cozo-core/benches/pokec.rs
+++ b/cozo-core/benches/pokec.rs
@@ -21,9 +21,8 @@ use lazy_static::{initialize, lazy_static};
 use rand::Rng;
 use rayon::prelude::*;
 use regex::Regex;
-use serde_json::json;
 
-use cozo::{DbInstance, NamedRows};
+use cozo::{DataValue, DbInstance, NamedRows};
 
 lazy_static! {
     static ref ITERATIONS: usize = {
@@ -97,7 +96,7 @@ lazy_static! {
             let file = File::open(&file_path).unwrap();
             let mut friends = Vec::with_capacity(batch_size);
             let mut users = Vec::with_capacity(batch_size);
-            let mut push_to_users = |row: Option<Vec<serde_json::Value>>, force: bool| {
+            let mut push_to_users = |row: Option<Vec<DataValue>>, force: bool| {
                 if let Some(row) = row {
                     users.push(row);
                 }
@@ -114,13 +113,14 @@ lazy_static! {
                                 "age".to_string(),
                             ],
                             rows: new_rows,
+                            next: None
                         },
                     )]))
                     .unwrap();
                 }
             };
 
-            let mut push_to_friends = |row: Option<Vec<serde_json::Value>>, force: bool| {
+            let mut push_to_friends = |row: Option<Vec<DataValue>>, force: bool| {
                 if let Some(row) = row {
                     friends.push(row);
                 }
@@ -133,6 +133,7 @@ lazy_static! {
                             NamedRows {
                                 headers: vec!["fr".to_string(), "to".to_string()],
                                 rows: new_rows.clone(),
+                                next: None,
                             },
                         ),
                         (
@@ -140,6 +141,7 @@ lazy_static! {
                             NamedRows {
                                 headers: vec!["fr".to_string(), "to".to_string()],
                                 rows: new_rows,
+                                next: None,
                             },
                         ),
                     ]))
@@ -155,7 +157,7 @@ lazy_static! {
                     n_rows += 2;
                     let fr = data.get(1).unwrap().as_str().parse::<i64>().unwrap();
                     let to = data.get(2).unwrap().as_str().parse::<i64>().unwrap();
-                    push_to_friends(Some(vec![json!(fr), json!(to)]), false);
+                    push_to_friends(Some(vec![DataValue::from(fr), DataValue::from(to)]), false);
                     continue;
                 }
                 if let Some(data) = node_re.captures(&line) {
@@ -165,7 +167,7 @@ lazy_static! {
                     let gender = data.get(3).unwrap().as_str();
                     let age = data.get(4).unwrap().as_str().parse::<i64>().unwrap();
                     push_to_users(
-                        Some(vec![json!(uid), json!(cmpl_pct), json!(gender), json!(age)]),
+                        Some(vec![DataValue::from(uid), DataValue::from(cmpl_pct), DataValue::from(gender), DataValue::from(age)]),
                         false,
                     );
                     continue;
@@ -176,10 +178,10 @@ lazy_static! {
                     let cmpl_pct = data.get(2).unwrap().as_str().parse::<i64>().unwrap();
                     push_to_users(
                         Some(vec![
-                            json!(uid),
-                            json!(cmpl_pct),
-                            serde_json::Value::Null,
-                            serde_json::Value::Null,
+                            DataValue::from(uid),
+                            DataValue::from(cmpl_pct),
+                            DataValue::Null,
+                            DataValue::Null,
                         ]),
                         false,
                     );
@@ -200,6 +202,7 @@ lazy_static! {
 }
 
 type QueryFn = fn() -> ();
+
 const READ_QUERIES: [QueryFn; 1] = [single_vertex_read];
 const WRITE_QUERIES: [QueryFn; 2] = [single_edge_write, single_vertex_write];
 const UPDATE_QUERIES: [QueryFn; 1] = [single_vertex_update];
@@ -233,7 +236,7 @@ fn single_vertex_read() {
     TEST_DB
         .run_script(
             "?[cmpl_pct, gender, age] := *user{uid: $id, cmpl_pct, gender, age}",
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -244,10 +247,10 @@ fn single_vertex_write() {
         if TEST_DB
             .run_script(
                 "?[uid, cmpl_pct, gender, age] <- [[$id, 0, null, null]] :put user {uid => cmpl_pct, gender, age}",
-                BTreeMap::from([("id".to_string(), json!(i))]),
+                BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
             )
             .is_ok() {
-            return
+            return;
         }
     }
     panic!()
@@ -266,7 +269,7 @@ fn single_edge_write() {
             {?[fr, to] <- [[$i, $j]] :put friends {fr, to}}
             {?[fr, to] <- [[$i, $j]] :put friends.rev {fr, to}}
             "#,
-                BTreeMap::from([("i".to_string(), json!(i)), ("j".to_string(), json!(j))]),
+                BTreeMap::from([("i".to_string(), DataValue::from(i as i64)), ("j".to_string(), DataValue::from(j as i64))]),
             )
             .is_ok()
         {
@@ -296,7 +299,7 @@ fn single_vertex_update() {
             ?[uid, cmpl_pct, age, gender] := uid = $id, *user{uid, age, gender}, cmpl_pct = -1
             :put user {uid => cmpl_pct, age, gender}
             "#,
-                BTreeMap::from([("id".to_string(), json!(i))]),
+                BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
             )
             .is_ok()
         {
@@ -345,7 +348,7 @@ fn expansion_1_plain() {
     TEST_DB
         .run_script(
             "?[to] := *friends{fr: $id, to}",
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -356,7 +359,7 @@ fn expansion_1_filter() {
     TEST_DB
         .run_script(
             "?[to] := *friends{fr: $id, to}, *user{uid: to, age}, age ~ 0 >= 18",
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -367,7 +370,7 @@ fn expansion_2_plain() {
     TEST_DB
         .run_script(
             "?[to] := *friends{fr: $id, to: a}, *friends{fr: a, to}",
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -376,11 +379,11 @@ fn expansion_2_filter() {
     let mut rng = rand::thread_rng();
     let i = rng.gen_range(1..SIZES.0);
     TEST_DB
-            .run_script(
-                "?[to] := *friends{fr: $id, to: a}, *friends{fr: a, to}, *user{uid: to, age}, age ~ 0 >= 18",
-                BTreeMap::from([("id".to_string(), json!(i))]),
-            )
-            .unwrap();
+        .run_script(
+            "?[to] := *friends{fr: $id, to: a}, *friends{fr: a, to}, *user{uid: to, age}, age ~ 0 >= 18",
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
+        )
+        .unwrap();
 }
 
 fn expansion_3_plain() {
@@ -393,7 +396,7 @@ fn expansion_3_plain() {
             l2[to] := l1[fr], *friends{fr, to}
             ?[to] := l2[fr], *friends{fr, to}
             "#,
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -407,7 +410,7 @@ fn expansion_3_filter() {
                         l2[to] := l1[fr], *friends{fr, to}
                         ?[to] := l2[fr], *friends{fr, to}, *user{uid: to, age}, age ~ 0 >= 18
                         "#,
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -422,7 +425,7 @@ fn expansion_4_plain() {
                         l3[to] := l2[fr], *friends{fr, to}
                         ?[to] := l3[fr], *friends{fr, to}
                         "#,
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -437,7 +440,7 @@ fn expansion_4_filter() {
                         l3[to] := l2[fr], *friends{fr, to}
                         ?[to] := l3[fr], *friends{fr, to}
                         "#,
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -452,7 +455,7 @@ fn neighbours_2_plain() {
             ?[to] := l1[to]
             ?[to] := l1[fr], *friends{fr, to}
             "#,
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -467,7 +470,7 @@ fn neighbours_2_filter_only() {
             ?[to] := l1[to], *user{uid: to, age}, age ~ 0 >= 18
             ?[to] := l1[fr], *friends{fr, to}, *user{uid: to, age}, age ~ 0 >= 18
             "#,
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -482,7 +485,7 @@ fn neighbours_2_data_only() {
             ?[to, age, cmpl_pct, gender] := l1[to], *user{uid: to, age, cmpl_pct, gender}
             ?[to, age, cmpl_pct, gender] := l1[fr], *friends{fr, to}, *user{uid: to, age, cmpl_pct, gender}
             "#,
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -497,7 +500,7 @@ fn neighbours_2_filter_data() {
             ?[to] := l1[to], *user{uid: to, age, cmpl_pct, gender}, age ~ 0 >= 18
             ?[to] := l1[fr], *friends{fr, to}, *user{uid: to, age, cmpl_pct, gender}, age ~ 0 >= 18
             "#,
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -510,7 +513,7 @@ fn pattern_cycle() {
             r#"
             ?[n, m] := n = $id, *friends{fr: n, to: m}, *friends.rev{fr: m, to: n}
             "#,
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -528,7 +531,7 @@ fn pattern_long() {
 
                 :limit 1
             "#,
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -543,7 +546,7 @@ fn pattern_short() {
 
             :limit 1
             "#,
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -675,6 +678,7 @@ fn bench_pattern_long(b: &mut Bencher) {
     initialize(&TEST_DB);
     b.iter(pattern_long)
 }
+
 #[bench]
 fn bench_pattern_short(b: &mut Bencher) {
     initialize(&TEST_DB);
diff --git a/cozo-core/benches/time_travel.rs b/cozo-core/benches/time_travel.rs
index 73d3705d..042bdc54 100644
--- a/cozo-core/benches/time_travel.rs
+++ b/cozo-core/benches/time_travel.rs
@@ -10,12 +10,11 @@
 
 extern crate test;
 
-use cozo::{DbInstance, NamedRows};
+use cozo::{DataValue, DbInstance, NamedRows, Validity};
 use itertools::Itertools;
 use lazy_static::{initialize, lazy_static};
 use rand::Rng;
 use rayon::prelude::*;
-use serde_json::json;
 use std::cmp::max;
 use std::collections::BTreeMap;
 use std::time::Instant;
@@ -28,7 +27,8 @@ fn insert_data(db: &DbInstance) {
         "plain".to_string(),
         NamedRows {
             headers: vec!["k".to_string(), "v".to_string()],
-            rows: (0..10000).map(|i| vec![json!(i), json!(i)]).collect_vec(),
+            rows: (0..10000).map(|i| vec![DataValue::from(i as i64), DataValue::from(i as i64)]).collect_vec(),
+            next: None,
         },
     );
     db.import_relations(to_import).unwrap();
@@ -41,8 +41,13 @@ fn insert_data(db: &DbInstance) {
         NamedRows {
             headers: vec!["k".to_string(), "vld".to_string(), "v".to_string()],
             rows: (0..10000)
-                .map(|i| vec![json!(i), json!([0, true]), json!(i)])
+                .map(|i| vec![
+                    DataValue::from(i as i64),
+                    DataValue::Validity(Validity::from((0, true))),
+                    DataValue::from(i as i64),
+                ])
                 .collect_vec(),
+            next: None,
         },
     );
     db.import_relations(to_import).unwrap();
@@ -55,8 +60,13 @@ fn insert_data(db: &DbInstance) {
         NamedRows {
             headers: vec!["k".to_string(), "vld".to_string(), "v".to_string()],
             rows: (0..10000)
-                .flat_map(|i| (0..10).map(move |vld| vec![json!(i), json!([vld, true]), json!(i)]))
+                .flat_map(|i| (0..10).map(move |vld| vec![
+                    DataValue::from(i as i64),
+                    DataValue::Validity(Validity::from((vld, true))),
+                    DataValue::from(i as i64),
+                ]))
                 .collect_vec(),
+            next: None,
         },
     );
     db.import_relations(to_import).unwrap();
@@ -69,8 +79,13 @@ fn insert_data(db: &DbInstance) {
         NamedRows {
             headers: vec!["k".to_string(), "vld".to_string(), "v".to_string()],
             rows: (0..10000)
-                .flat_map(|i| (0..100).map(move |vld| vec![json!(i), json!([vld, true]), json!(i)]))
+                .flat_map(|i| (0..100).map(move |vld| vec![
+                    DataValue::from(i as i64),
+                    DataValue::Validity(Validity::from((vld, true))),
+                    DataValue::from(i as i64),
+                ]))
                 .collect_vec(),
+            next: None,
         },
     );
     db.import_relations(to_import).unwrap();
@@ -84,9 +99,14 @@ fn insert_data(db: &DbInstance) {
             headers: vec!["k".to_string(), "vld".to_string(), "v".to_string()],
             rows: (0..10000)
                 .flat_map(|i| {
-                    (0..1000).map(move |vld| vec![json!(i), json!([vld, true]), json!(i)])
+                    (0..1000).map(move |vld| vec![
+                        DataValue::from(i as i64),
+                        DataValue::Validity((vld, true).into()),
+                        DataValue::from(i as i64),
+                    ])
                 })
                 .collect_vec(),
+            next: None,
         },
     );
     db.import_relations(to_import).unwrap();
@@ -124,7 +144,7 @@ fn single_plain_read() {
     TEST_DB
         .run_script(
             "?[v] := *plain{k: $id, v}",
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -179,7 +199,7 @@ fn single_tt_read(k: usize) {
             "#,
                 k
             ),
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
@@ -194,7 +214,7 @@ fn single_tt_travel_read(k: usize) {
             "#,
                 k
             ),
-            BTreeMap::from([("id".to_string(), json!(i))]),
+            BTreeMap::from([("id".to_string(), DataValue::from(i as i64))]),
         )
         .unwrap();
 }
diff --git a/cozo-core/benches/wiki_pagerank.rs b/cozo-core/benches/wiki_pagerank.rs
index 4bbf839f..03675357 100644
--- a/cozo-core/benches/wiki_pagerank.rs
+++ b/cozo-core/benches/wiki_pagerank.rs
@@ -19,9 +19,8 @@ use std::{env, io};
 use test::Bencher;
 
 use lazy_static::{initialize, lazy_static};
-use serde_json::json;
 
-use cozo::{DbInstance, NamedRows};
+use cozo::{DbInstance, NamedRows, DataValue};
 
 lazy_static! {
     static ref TEST_DB: DbInstance = {
@@ -53,7 +52,7 @@ lazy_static! {
             let mut splits = line.split_whitespace();
             let fr = splits.next().unwrap();
             let to = splits.next().unwrap();
-            articles.push(vec![json!(fr.parse::<i32>().unwrap()), json!(to.parse::<i32>().unwrap())])
+            articles.push(vec![DataValue::from(fr.parse::<i64>().unwrap()), DataValue::from(to.parse::<i64>().unwrap())])
         }
         db.import_relations(BTreeMap::from([("article".to_string(), NamedRows {
             headers: vec![
@@ -61,6 +60,7 @@ lazy_static! {
                 "to".to_string(),
             ],
             rows: articles,
+            next: None,
         })])).unwrap();
         dbg!(import_time.elapsed());
         db
diff --git a/cozo-core/src/data/value.rs b/cozo-core/src/data/value.rs
index 123f2b98..ad91dd99 100644
--- a/cozo-core/src/data/value.rs
+++ b/cozo-core/src/data/value.rs
@@ -60,8 +60,8 @@ impl Hash for RegexWrapper {
 
 impl Serialize for RegexWrapper {
     fn serialize<S>(&self, _serializer: S) -> std::result::Result<S::Ok, S::Error>
-    where
-        S: serde::Serializer,
+        where
+            S: serde::Serializer,
     {
         panic!("serializing regex");
     }
@@ -69,8 +69,8 @@ impl Serialize for RegexWrapper {
 
 impl<'de> Deserialize<'de> for RegexWrapper {
     fn deserialize<D>(_deserializer: D) -> std::result::Result<Self, D::Error>
-    where
-        D: Deserializer<'de>,
+        where
+            D: Deserializer<'de>,
     {
         panic!("deserializing regex");
     }
@@ -98,30 +98,30 @@ impl PartialOrd for RegexWrapper {
 
 /// Timestamp part of validity
 #[derive(
-    Copy,
-    Clone,
-    Eq,
-    PartialEq,
-    Ord,
-    PartialOrd,
-    serde_derive::Deserialize,
-    serde_derive::Serialize,
-    Hash,
-    Debug,
+Copy,
+Clone,
+Eq,
+PartialEq,
+Ord,
+PartialOrd,
+serde_derive::Deserialize,
+serde_derive::Serialize,
+Hash,
+Debug,
 )]
 pub struct ValidityTs(pub Reverse<i64>);
 
 /// Validity for time travel
 #[derive(
-    Copy,
-    Clone,
-    Eq,
-    PartialEq,
-    Ord,
-    PartialOrd,
-    serde_derive::Deserialize,
-    serde_derive::Serialize,
-    Hash,
+Copy,
+Clone,
+Eq,
+PartialEq,
+Ord,
+PartialOrd,
+serde_derive::Deserialize,
+serde_derive::Serialize,
+Hash,
 )]
 pub struct Validity {
     /// Timestamp, sorted descendingly
@@ -130,9 +130,18 @@ pub struct Validity {
     pub is_assert: Reverse<bool>,
 }
 
+impl From<(i64, bool)> for Validity {
+    fn from(value: (i64, bool)) -> Self {
+        Self {
+            timestamp: ValidityTs(Reverse(value.0)),
+            is_assert: Reverse(value.1),
+        }
+    }
+}
+
 /// A Value in the database
 #[derive(
-    Clone, PartialEq, Eq, PartialOrd, Ord, serde_derive::Deserialize, serde_derive::Serialize, Hash,
+Clone, PartialEq, Eq, PartialOrd, Ord, serde_derive::Deserialize, serde_derive::Serialize, Hash,
 )]
 pub enum DataValue {
     /// null
@@ -207,8 +216,8 @@ struct VecBytes<'a>(&'a [u8]);
 
 impl serde::Serialize for VecBytes<'_> {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: Serializer,
+        where
+            S: Serializer,
     {
         serializer.serialize_bytes(self.0)
     }
@@ -216,8 +225,8 @@ impl serde::Serialize for VecBytes<'_> {
 
 impl serde::Serialize for Vector {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: Serializer,
+        where
+            S: Serializer,
     {
         let mut state = serializer.serialize_tuple(2)?;
         match self {
@@ -244,8 +253,8 @@ impl serde::Serialize for Vector {
 
 impl<'de> serde::Deserialize<'de> for Vector {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: Deserializer<'de>,
+        where
+            D: Deserializer<'de>,
     {
         deserializer.deserialize_tuple(2, VectorVisitor)
     }
@@ -260,8 +269,8 @@ impl<'de> Visitor<'de> for VectorVisitor {
         formatter.write_str("vector representation")
     }
     fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
-    where
-        A: SeqAccess<'de>,
+        where
+            A: SeqAccess<'de>,
     {
         let tag: u8 = seq
             .next_element()?