diff --git a/WelsonJS.Toolkit/WelsonJS.Esent/EsentDatabase.cs b/WelsonJS.Toolkit/WelsonJS.Esent/EsentDatabase.cs
index ef0a71e..5c04948 100644
--- a/WelsonJS.Toolkit/WelsonJS.Esent/EsentDatabase.cs
+++ b/WelsonJS.Toolkit/WelsonJS.Esent/EsentDatabase.cs
@@ -36,11 +36,11 @@ namespace WelsonJS.Esent
         {
             _logger = logger ?? new TraceLogger();
 
-            _primaryKey = schema.PrimaryKey;
-
             if (schema == null)
                 throw new ArgumentNullException(nameof(schema));
 
+            _primaryKey = schema.PrimaryKey;
+
             if (_primaryKey == null)
                 throw new ArgumentNullException();
 
diff --git a/WelsonJS.Toolkit/WelsonJS.Esent/README.md b/WelsonJS.Toolkit/WelsonJS.Esent/README.md
index 38d3a7d..e3327d3 100644
--- a/WelsonJS.Toolkit/WelsonJS.Esent/README.md
+++ b/WelsonJS.Toolkit/WelsonJS.Esent/README.md
@@ -11,7 +11,7 @@ For more details, refer to the [WelsonJS Documentation](https://catswords-oss.rd
 ```csharp
 using WelsonJS.Esent;
 
-// connect the database to manage an instances
+// connect the database to manage instances
 Schema schema = new Schema("Instances", new List<Column>
 {
     new Column("InstanceId", typeof(string), 255),
diff --git a/WelsonJS.Toolkit/WelsonJS.Esent/assets/docs/README.md b/WelsonJS.Toolkit/WelsonJS.Esent/assets/docs/README.md
index 38d3a7d..e3327d3 100644
--- a/WelsonJS.Toolkit/WelsonJS.Esent/assets/docs/README.md
+++ b/WelsonJS.Toolkit/WelsonJS.Esent/assets/docs/README.md
@@ -11,7 +11,7 @@ For more details, refer to the [WelsonJS Documentation](https://catswords-oss.rd
 ```csharp
 using WelsonJS.Esent;
 
-// connect the database to manage an instances
+// connect the database to manage instances
 Schema schema = new Schema("Instances", new List<Column>
 {
     new Column("InstanceId", typeof(string), 255),