diff --git a/CHANGELOG.md b/CHANGELOG.md
index 89226aa0..e8a303d2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+# v5.0.0 (Not Released Yet)
+
+Changed
+- Checks that primary key is defined in schema and throws an exception if not defined.
+
 # v4.7.0 (Not released yet)
 
 Chore
diff --git a/src/Schema/Grammar.php b/src/Schema/Grammar.php
index 26ef69e7..1ebc90e1 100644
--- a/src/Schema/Grammar.php
+++ b/src/Schema/Grammar.php
@@ -302,7 +302,7 @@ protected function addPrimaryKeys(Blueprint $blueprint)
         if (! is_null($primary = $this->getCommandByName($blueprint, 'primary'))) {
             return "primary key ({$this->columnize($primary->columns)})";
         }
-        return '';
+        throw new LogicException('Cloud Spanner require a primary key!');
     }
 
     /**
diff --git a/tests/Schema/BlueprintTest.php b/tests/Schema/BlueprintTest.php
index ece0b619..a8078319 100644
--- a/tests/Schema/BlueprintTest.php
+++ b/tests/Schema/BlueprintTest.php
@@ -150,6 +150,18 @@ public function testDropIndex(): void
         );
     }
 
+    public function test_no_primaryKey(): void
+    {
+        $this->expectException(LogicException::class);
+        $this->expectExceptionMessage('Cloud Spanner require a primary key!');
+
+        $blueprint = new Blueprint('test', function (Blueprint $table) {
+            $table->create();
+            $table->uuid('id');
+        });
+        $blueprint->toSql($this->getDefaultConnection(), new Grammar());
+    }
+
     public function testCompositePrimaryKey(): void
     {
         $conn = $this->getDefaultConnection();