Add new DB2NetDriver and obsolete DB2CoreDriver (#3559)

Co-authored-by: Frédéric Delaporte <12201973+fredericDelaporte@users.noreply.github.com>

Author: hazzik

src/NHibernate.Test/TestDialect.cs

@@ -123,10 +123,15 @@ public bool SupportsSqlType(SqlType sqlType)
 		/// </summary>
 		public virtual bool SupportsModuloOnDecimal => true;
 
+		/// <summary>
+		/// Supports sub-selects in order by clause
+		/// </summary>
+		public virtual bool SupportsSubSelectsInOrderBy => _dialect.SupportsScalarSubSelects;
+
 		/// <summary>
 		/// Supports aggregating sub-selects in order by clause
 		/// </summary>
-		public virtual bool SupportsAggregatingScalarSubSelectsInOrderBy => _dialect.SupportsScalarSubSelects;
+		public virtual bool SupportsAggregatingScalarSubSelectsInOrderBy => SupportsSubSelectsInOrderBy;
 
 		/// <summary>
 		/// Supports order by and limits/top in correlated sub-queries

src/NHibernate.Test/TestDialects/DB2TestDialect.cs

@@ -0,0 +1,16 @@
+namespace NHibernate.Test.TestDialects
+{
+	public class DB2TestDialect: TestDialect
+	{
+		public DB2TestDialect(Dialect.Dialect dialect) : base(dialect)
+		{
+		}
+
+		public override bool HasBrokenTypeInferenceOnSelectedParameters => true;
+		public override bool SupportsCancelQuery => false;
+		public override bool SupportsComplexExpressionInGroupBy => false;
+		public override bool SupportsNonDataBoundCondition => false;
+		public override bool SupportsSelectForUpdateWithPaging => false;
+		public override bool SupportsSubSelectsInOrderBy => false;
+	}
+}

src/NHibernate.TestDatabaseSetup/TestDatabaseSetup.cs

@@ -32,6 +32,9 @@ public class DatabaseSetup
 				{"NHibernate.Driver.OracleManagedDataClientDriver", SetupOracle},
 				{"NHibernate.Driver.OdbcDriver", SetupSqlServerOdbc},
 				{"NHibernate.Driver.SQLite20Driver", SetupSQLite},
+				{"NHibernate.Driver.DB2Driver", SetupDB2},
+				{"NHibernate.Driver.DB2CoreDriver", SetupDB2},
+				{"NHibernate.Driver.DB2NetDriver", SetupDB2},
 #if NETFX
 				{"NHibernate.Driver.SqlServerCeDriver", SetupSqlServerCe},
 				{"NHibernate.Driver.SapSQLAnywhere17Driver", SetupSqlAnywhere}
@@ -207,6 +210,10 @@ private static void SetupSQLite(Cfg.Configuration cfg)
 			}
 		}
 
+		private static void SetupDB2(Cfg.Configuration cfg)
+		{
+		}
+
 		private static void SetupOracle(Cfg.Configuration cfg)
 		{
 			// disabled until system password is set on TeamCity

src/NHibernate/Dialect/DB2Dialect.cs

@@ -214,6 +214,8 @@ public override bool SupportsSequences
 			get { return true; }
 		}
 
+		public override string QuerySequencesString => "select seqname from syscat.sequences";
+
 		/// <summary></summary>
 		public override bool SupportsLimit
 		{
@@ -311,6 +313,9 @@ public override string ForUpdateString
 
 		public override bool SupportsExistsInSelect => false;
 
+		/// <inheritdoc/>
+		public override bool SupportsHavingOnGroupedByComputation => false;
+
 		public override bool DoesReadCommittedCauseWritersToBlockReaders => true;
 
 		#endregion

src/NHibernate/Driver/DB2CoreDriver.cs

@@ -1,27 +1,19 @@
-using System.Data.Common;
-using NHibernate.SqlTypes;
+using System;
 
 namespace NHibernate.Driver
 {
 	/// <summary>
 	/// A NHibernate Driver for using the IBM.Data.DB2.Core DataProvider.
 	/// </summary>
-	public class DB2CoreDriver : DB2DriverBase
-	{		
-		public DB2CoreDriver() : base("IBM.Data.DB2.Core")
-		{
-		}
+	// Since v5.6
+	[Obsolete("Please use DB2NetDriver")]
+	public class DB2CoreDriver : DB2NetDriver
+	{
+		private static readonly INHibernateLogger Log = NHibernateLogger.For(typeof(DB2CoreDriver));
 
-		public override bool UseNamedPrefixInSql => true;
-
-		public override bool UseNamedPrefixInParameter => true;
-
-		public override string NamedPrefix => "@";
-
-		protected override void InitializeParameter(DbParameter dbParam, string name, SqlType sqlType)
+		public DB2CoreDriver() : base("IBM.Data.DB2.Core")
 		{
-			dbParam.ParameterName = FormatNameForParameter(name);
-			base.InitializeParameter(dbParam, name, sqlType);
+		    Log.Warn("DB2CoreDriver is obsolete, please use DB2NetDriver instead.");
 		}
 	}
 }

src/NHibernate/Driver/DB2NetDriver.cs

@@ -0,0 +1,29 @@
+using System.Data.Common;
+using NHibernate.SqlTypes;
+
+namespace NHibernate.Driver
+{
+	/// <summary>
+	/// A NHibernate Driver for using the Net5.IBM.Data.Db2/Net.IBM.Data.Db2 DataProvider.
+	/// </summary>
+	public class DB2NetDriver : DB2DriverBase
+	{
+		private protected DB2NetDriver(string assemblyName) : base(assemblyName)
+		{
+		}
+
+		public DB2NetDriver() : base("IBM.Data.Db2")
+		{
+		}
+
+		public override bool UseNamedPrefixInSql => true;
+		public override bool UseNamedPrefixInParameter => true;
+		public override string NamedPrefix => "@";
+
+		protected override void InitializeParameter(DbParameter dbParam, string name, SqlType sqlType)
+		{
+			dbParam.ParameterName = FormatNameForParameter(name);
+			base.InitializeParameter(dbParam, name, sqlType);
+		}
+	}
+}