fix: create database with wal_retention_period in docs/examples/csharp

docs/examples/csharp/influxdbLine/Program.cs

@@ -48,7 +48,7 @@ namespace TDengineExample
 
         static void PrepareDatabase(IntPtr conn)
         {
-            IntPtr res = TDengine.Query(conn, "CREATE DATABASE test");
+            IntPtr res = TDengine.Query(conn, "CREATE DATABASE test WAL_RETENTION_PERIOD 3600");
             if (TDengine.ErrorNo(res) != 0)
             {
                 throw new Exception("failed to create database, reason: " + TDengine.Error(res));

docs/examples/csharp/optsTelnet/Program.cs

@@ -58,7 +58,7 @@ namespace TDengineExample
 
         static void PrepareDatabase(IntPtr conn)
         {
-            IntPtr res = TDengine.Query(conn, "CREATE DATABASE test");
+            IntPtr res = TDengine.Query(conn, "CREATE DATABASE test WAL_RETENTION_PERIOD 3600");
             if (TDengine.ErrorNo(res) != 0)
             {
                 throw new Exception("failed to create database, reason: " + TDengine.Error(res));

docs/examples/csharp/sqlInsert/Program.cs

@@ -11,7 +11,7 @@ namespace TDengineExample
             IntPtr conn = GetConnection();
             try
             {
-                IntPtr res = TDengine.Query(conn, "CREATE DATABASE power");
+                IntPtr res = TDengine.Query(conn, "CREATE DATABASE power WAL_RETENTION_PERIOD 3600");
                 CheckRes(conn, res, "failed to create database");
                 res = TDengine.Query(conn, "USE power");
                 CheckRes(conn, res, "failed to change database");

docs/examples/csharp/stmtInsert/Program.cs

@@ -76,7 +76,7 @@ namespace TDengineExample
 
         static void PrepareSTable()
         {
-            IntPtr res = TDengine.Query(conn, "CREATE DATABASE power");
+            IntPtr res = TDengine.Query(conn, "CREATE DATABASE power WAL_RETENTION_PERIOD 3600");
             CheckResPtr(res, "failed to create database");
             res = TDengine.Query(conn, "USE power");
             CheckResPtr(res, "failed to change database");