Override current_timestamp in Firebird4

Author: hazzik

src/NHibernate/Dialect/Firebird4Dialect.cs

@@ -1,6 +1,13 @@
+using NHibernate.Dialect.Function;
+
 namespace NHibernate.Dialect
 {
 	public class Firebird4Dialect: FirebirdDialect
 	{
+		protected override void RegisterFunctions()
+		{
+			base.RegisterFunctions();
+			RegisterFunction("current_timestamp", new NoArgSQLFunction("localtimestamp", NHibernateUtil.LocalDateTime, false));
+		}
 	}
 }

src/NHibernate/Dialect/FirebirdDialect.cs

@@ -152,19 +152,6 @@ public override SqlString Render(IList args, ISessionFactoryImplementor factory)
 			}
 		}
 
-		[Serializable]
-		private class CurrentTimeStamp : NoArgSQLFunction
-		{
-			public CurrentTimeStamp() : base("current_timestamp", NHibernateUtil.LocalDateTime, true)
-			{
-			}
-
-			public override SqlString Render(IList args, ISessionFactoryImplementor factory)
-			{
-				return new SqlString(Name);
-			}
-		}
-
 		public override IDataBaseSchema GetDataBaseSchema(DbConnection connection)
 		{
 			return new FirebirdDataBaseSchema(connection);
@@ -474,7 +461,7 @@ protected virtual void RegisterFunctions()
 
 		private void OverrideStandardHQLFunctions()
 		{
-			RegisterFunction("current_timestamp", new CurrentTimeStamp());
+			RegisterFunction("current_timestamp", new NoArgSQLFunction("current_timestamp", NHibernateUtil.LocalDateTime, false));
 			RegisterFunction("current_date", new NoArgSQLFunction("current_date", NHibernateUtil.LocalDate, false));
 			RegisterFunction("length", new StandardSafeSQLFunction("char_length", NHibernateUtil.Int64, 1));
 			RegisterFunction("nullif", new StandardSafeSQLFunction("nullif", 2));