diff --git a/CHANGELOG.md b/CHANGELOG.md
index 955f1c2..a8a8b8f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changes
 
+**3.1.0**
+
+* The `values` paramter of `PostgresqlAccess.query` and `execute` must be `Map`.
+
 **3.0.1**
 
 * `isValidOid()` introduced the `ignoreLength` argument.
diff --git a/lib/src/postgresql/postgresql.dart b/lib/src/postgresql/postgresql.dart
index 265e21d..7c39158 100644
--- a/lib/src/postgresql/postgresql.dart
+++ b/lib/src/postgresql/postgresql.dart
@@ -42,9 +42,11 @@ class PostgresqlAccess implements Access {
 
   /// Queues a command for execution, and when done, returns the number of rows
   /// affected by the SQL command.
-  Future<int> execute(String sql, [values]) => conn.execute(sql, values);
+  Future<int> execute(String sql, [Map? values])
+  => conn.execute(sql, values);
   /// Queue a SQL query to be run, returning a [Stream] of rows.
-  Stream<Row> query(String sql, [values]) => conn.query(sql, values);
+  Stream<Row> query(String sql, [Map? values])
+  => conn.query(sql, values);
 
   ///Clear the cache.
   void clearCache() {