diff --git a/src/cmd/import.rs b/src/cmd/import.rs
index ac0777a..66a1207 100644
--- a/src/cmd/import.rs
+++ b/src/cmd/import.rs
@@ -40,7 +40,7 @@ fn import_autojump(db: &mut Database, buffer: &str) -> Result<()> {
         // take a while to normalize.
         rank = sigmoid(rank);
 
-        db.add_unchecked(path, rank, 0);
+        db.add_unchecked_merge(path, rank, 0);
     }
 
     if db.dirty() {
@@ -65,7 +65,7 @@ fn import_z(db: &mut Database, buffer: &str) -> Result<()> {
 
         let path = split.next().with_context(|| format!("invalid entry: {line}"))?;
 
-        db.add_unchecked(path, rank, last_accessed);
+        db.add_unchecked_merge(path, rank, last_accessed);
     }
 
     if db.dirty() {
@@ -107,12 +107,12 @@ mod tests {
         println!("got: {:?}", &db.dirs());
 
         let exp = [
-            Dir { path: "/baz".into(), rank: sigmoid(7.0), last_accessed: 0 },
-            Dir { path: "/corge/grault/garply".into(), rank: 6.0, last_accessed: 600 },
-            Dir { path: "/foo/bar".into(), rank: 9.0 + sigmoid(2.0), last_accessed: 900 },
             Dir { path: "/quux/quuz".into(), rank: 1.0 + sigmoid(5.0), last_accessed: 100 },
+            Dir { path: "/corge/grault/garply".into(), rank: 6.0, last_accessed: 600 },
             Dir { path: "/waldo/fred/plugh".into(), rank: 3.0, last_accessed: 300 },
             Dir { path: "/xyzzy/thud".into(), rank: 8.0, last_accessed: 800 },
+            Dir { path: "/foo/bar".into(), rank: 9.0 + sigmoid(2.0), last_accessed: 900 },
+            Dir { path: "/baz".into(), rank: sigmoid(7.0), last_accessed: 0 },
         ];
         println!("exp: {exp:?}");
 
@@ -148,12 +148,12 @@ mod tests {
         println!("got: {:?}", &db.dirs());
 
         let exp = [
-            Dir { path: "/baz".into(), rank: 7.0, last_accessed: 700 },
-            Dir { path: "/corge/grault/garply".into(), rank: 6.0, last_accessed: 600 },
-            Dir { path: "/foo/bar".into(), rank: 11.0, last_accessed: 900 },
             Dir { path: "/quux/quuz".into(), rank: 10.0, last_accessed: 500 },
+            Dir { path: "/corge/grault/garply".into(), rank: 6.0, last_accessed: 600 },
             Dir { path: "/waldo/fred/plugh".into(), rank: 3.0, last_accessed: 300 },
             Dir { path: "/xyzzy/thud".into(), rank: 8.0, last_accessed: 800 },
+            Dir { path: "/foo/bar".into(), rank: 11.0, last_accessed: 900 },
+            Dir { path: "/baz".into(), rank: 7.0, last_accessed: 700 },
         ];
         println!("exp: {exp:?}");
 
diff --git a/src/db/mod.rs b/src/db/mod.rs
index e0d31a6..d3982fb 100644
--- a/src/db/mod.rs
+++ b/src/db/mod.rs
@@ -100,6 +100,7 @@ impl Database {
     /// directory is already in the database, it is expected that the user
     /// either does a check before calling this, or calls `dedup()`
     /// afterward.
+    #[cfg(test)]
     pub fn add_unchecked(&mut self, path: impl AsRef<str> + Into<String>, rank: Rank, now: Epoch) {
         let path_s: String = path.into();
         let _ = self.conn.execute(
@@ -109,6 +110,20 @@ impl Database {
         self.dirty = true;
     }
 
+    /// choose the max `now`
+    /// sum `rank`
+    pub fn add_unchecked_merge(&mut self, path: impl AsRef<str> + Into<String>, rank: Rank, now: Epoch) {
+        let path_s: String = path.into();
+        let _ = self.conn.execute(
+            "INSERT INTO dirs (path, rank, last_accessed) VALUES (?1, ?2, ?3)
+             ON CONFLICT(path) DO UPDATE SET
+               rank = dirs.rank + excluded.rank,
+               last_accessed = MAX(dirs.last_accessed, excluded.last_accessed)",
+            params![&path_s, rank, now],
+        );
+        self.dirty = true;
+    }
+
     /// Increments the rank and updates the last_accessed of a directory, or
     /// creates it if it does not exist.
     pub fn add_update(&mut self, path: impl AsRef<str> + Into<String>, by: Rank, now: Epoch) {
@@ -215,6 +230,7 @@ impl Database {
         // Using path as PRIMARY KEY ensures uniqueness, nothing to do here.
     }
 
+    #[cfg(test)]
     pub fn sort_by_path(&mut self) {
         // Sorting is done at query time in the sqlite-backed implementation.
     }