SqlServer provider: Code from providers older than v13 merged into v13

- Azure version is now based on v13 (MS keeps version 12 but functionality
  is way ahead even v13, according to MS)
- '==null','!=null' checks replaced with 'is null'/'is not null' checks

Author: alex-kulakov

Orm/Xtensive.Orm.SqlServer/Orm.Providers.SqlServer/SqlCompiler.cs

@@ -37,7 +37,7 @@ protected override SqlProvider VisitFreeText(FreeTextProvider provider)
       var table = Mapping[index.ReflectedType];
       var columns = provider.Header.Columns.Select(column => column.Name).ToList();
 
-      if (provider.TopN == null) {
+      if (provider.TopN is null) {
         fromTable = SqlDml.FreeTextTable(table, criteriaBinding.ParameterReference, columns);
         bindings = new[] {criteriaBinding};
       }
@@ -69,7 +69,7 @@ protected override SqlProvider VisitContainsTable(ContainsTableProvider provider
       var columns = provider.Header.Columns.Select(column => column.Name).ToList();
 
       var targetColumnNames = provider.TargetColumns.Select(c => c.Name).ToArray();
-      if (provider.TopN == null) {
+      if (provider.TopN is null) {
         fromTable = SqlDml.ContainsTable(table, criteriaBinding.ParameterReference, columns, targetColumnNames);
         bindings = new[] { criteriaBinding };
       }

Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Azure/Driver.cs

@@ -5,11 +5,10 @@
 // Created:    2009.07.07
 
 using Xtensive.Sql.Info;
-using SqlServerConnection = Microsoft.Data.SqlClient.SqlConnection;
 
 namespace Xtensive.Sql.Drivers.SqlServer.Azure
 {
-  internal class Driver : v12.Driver
+  internal class Driver : v13.Driver
   {
     protected override Model.Extractor CreateExtractor()
     {

Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Azure/Extractor.cs

@@ -6,7 +6,7 @@
 
 namespace Xtensive.Sql.Drivers.SqlServer.Azure
 {
-  internal class Extractor : v12.Extractor
+  internal class Extractor : v13.Extractor
   {
     // Constructors
 

Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Azure/ServerInfoProvider.cs

@@ -4,11 +4,10 @@
 // Created by: Dmitri Maximov
 // Created:    2009.11.09
 
-using SqlServerConnection = Microsoft.Data.SqlClient.SqlConnection;
 
 namespace Xtensive.Sql.Drivers.SqlServer.Azure
 {
-  internal class ServerInfoProvider : v12.ServerInfoProvider
+  internal class ServerInfoProvider : v13.ServerInfoProvider
   {
     // Constructors
 

Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Connection.cs

@@ -40,7 +40,7 @@ public override void Open()
       }
       else {
         var connectionAccessorEx = Extensions.Get<DbConnectionAccessorExtension>();
-        if (connectionAccessorEx == null) {
+        if (connectionAccessorEx is null) {
           OpenWithCheckFast(DefaultCheckConnectionQuery);
         }
         else {
@@ -58,7 +58,7 @@ public override Task OpenAsync(CancellationToken cancellationToken)
       }
 
       var connectionAccessorEx = Extensions.Get<DbConnectionAccessorExtension>();
-      if (connectionAccessorEx == null) {
+      if (connectionAccessorEx is null) {
         return OpenWithCheckFastAsync(DefaultCheckConnectionQuery, cancellationToken);
       }
       else {
@@ -78,7 +78,7 @@ public override void OpenAndInitialize(string initializationScript)
         ? DefaultCheckConnectionQuery
         : initializationScript;
       var connectionAccessorEx = Extensions.Get<DbConnectionAccessorExtension>();
-      if (connectionAccessorEx == null) {
+      if (connectionAccessorEx is null) {
         OpenWithCheckFast(script);
       }
       else {
@@ -97,7 +97,7 @@ public override Task OpenAndInitializeAsync(string initializationScript, Cancell
         ? DefaultCheckConnectionQuery
         : initializationScript;
       var connectionAccessorEx = Extensions.Get<DbConnectionAccessorExtension>();
-      return connectionAccessorEx == null
+      return connectionAccessorEx is null
         ? OpenWithCheckFastAsync(script, token)
         : OpenWithCheckAndNotificationAsync(script, connectionAccessorEx, token);
     }

Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/Driver.cs

@@ -28,23 +28,26 @@ public override SqlExceptionType GetExceptionType(Exception exception)
 
     public override SqlExceptionInfo GetExceptionInfo(Exception exception)
     {
-      var nativeException = exception as SqlException;
-      if (nativeException==null)
+      if (exception is not SqlException nativeException)
         return SqlExceptionInfo.Create(SqlExceptionType.Unknown);
       int errorCode = nativeException.Number;
-      string errorMessage = nativeException.Message;
-      if (errorCode==-2)
-        return SqlExceptionInfo.Create(SqlExceptionType.OperationTimeout);
-      if (errorCode==1205)
-        return SqlExceptionInfo.Create(SqlExceptionType.Deadlock);
+      switch (errorCode) {
+        case -2:
+          return SqlExceptionInfo.Create(SqlExceptionType.OperationTimeout);
+        case 1205:
+          return SqlExceptionInfo.Create(SqlExceptionType.Deadlock);
+        case 229:
+        case 230:
+          return SqlExceptionInfo.Create(SqlExceptionType.Unknown);
+      }
+
       if ((errorCode >= 3950 && errorCode <= 3961) || errorCode==3966 || errorCode==3971)
         return SqlExceptionInfo.Create(SqlExceptionType.SerializationFailure);
-      if (errorCode==229 || errorCode==230)
-        return SqlExceptionInfo.Create(SqlExceptionType.Unknown);
       if (errorCode >= 100 && errorCode <= 499)
         return SqlExceptionInfo.Create(SqlExceptionType.SyntaxError);
+
       var info = new SqlExceptionInfo();
-      if (TryProvideErrorContext(errorCode, errorMessage, info)) {
+      if (TryProvideErrorContext(errorCode, nativeException.Message, info)) {
         info.Lock();
         return info;
       }

Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/DriverFactory.cs

@@ -22,6 +22,12 @@ namespace Xtensive.Sql.Drivers.SqlServer
   /// </summary>
   public class DriverFactory : SqlDriverFactory
   {
+    private const int SqlServer2016MajorVersion = 13;
+    private const int SqlServer2017MajorVersion = 14;
+    private const int SqlServer2019MajorVersion = 15;
+    private const int SqlServer2022MajorVersion = 16;
+    private const int SqlServer2025MajorVersion = 17;
+
     private const string CheckConnectionQuery = "SELECT TOP(0) 0;";
     private const string PoolingOffCommand = "pooling = false";
 
@@ -113,12 +119,9 @@ protected override string BuildConnectionString(UrlInfo url)
       builder.Encrypt = url.Secure;
 
       // host, port, database
-      if (url.Port==0) {
-        builder.DataSource = url.Host;
-      }
-      else {
-        builder.DataSource = url.Host + "," + url.Port;
-      }
+      builder.DataSource = url.Port==0
+        ? url.Host
+        : url.Host + "," + url.Port;
 
       builder.InitialCatalog = url.Resource ?? string.Empty;
 
@@ -183,7 +186,7 @@ protected override async Task<SqlDriver> CreateDriverAsync(
           : await CreateMessageParserAsync(connection, token).ConfigureAwait(false);
 
         var versionString = isForcedVersion
-          ? isForcedAzure ? "10.0.0.0" : forcedServerVersion
+          ? isForcedAzure ? ForcedAzureVersion : forcedServerVersion
           : connection.ServerVersion ?? string.Empty;
         var version = new Version(versionString);
         var defaultSchema = await GetDefaultSchemaAsync(connection, token: token).ConfigureAwait(false);
@@ -207,15 +210,11 @@ private static SqlDriver CreateDriverInstance(string connectionString, bool isAz
         return new Azure.Driver(coreServerInfo, parser, isEnsureAlive);
       }
 
-      if (version.Major < 9) {
-        throw new NotSupportedException(Strings.ExSqlServerBelow2005IsNotSupported);
+      if (version.Major < SqlServer2016MajorVersion) {
+        throw new NotSupportedException(Strings.ExSqlServerBelow2016IsNotSupported);
       }
       return version.Major switch {
-        9 => new v09.Driver(coreServerInfo, parser, isEnsureAlive),
-        10 => new v10.Driver(coreServerInfo, parser, isEnsureAlive),
-        11 => new v11.Driver(coreServerInfo, parser, isEnsureAlive),
-        12 => new v12.Driver(coreServerInfo, parser, isEnsureAlive),
-        13 => new v13.Driver(coreServerInfo, parser, isEnsureAlive),
+        SqlServer2016MajorVersion => new v13.Driver(coreServerInfo, parser, isEnsureAlive),
         _ => new v13.Driver(coreServerInfo, parser, isEnsureAlive)
       };
     }

Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/SqlServerTypeMapper.cs

@@ -1,4 +1,4 @@
-// Copyright (C) 2012-2021 Xtensive LLC.
+// Copyright (C) 2012-2021 Xtensive LLC.
 // This code is distributed under MIT license terms.
 // See the License.txt file in the project root for more information.
 // Created by: Denis Krjuchkov
@@ -22,7 +22,7 @@ internal abstract class SqlServerTypeMapper : CustomTypeMapper
 
     public override void BindValue(DbParameter parameter, object value)
     {
-      if (value==null) {
+      if (value is null) {
         parameter.Value = DBNull.Value;
         return;
       }

Orm/Xtensive.Orm.SqlServer/Sql.Drivers.SqlServer/v13/ColumnResolver.cs

@@ -0,0 +1,61 @@
+// Copyright (C) 2003-2010 Xtensive LLC.
+// All rights reserved.
+// For conditions of distribution and use, see license.
+// Created by: Dmitri Maximov
+// Created:    2009.08.12
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Xtensive.Sql.Model;
+
+namespace Xtensive.Sql.Drivers.SqlServer.v13
+{
+  internal sealed class ColumnResolver
+  {
+    public DataTable Table;
+    private List<ColumnIndexMapping> columnMappings;
+
+    private class ColumnIndexMapping
+    {
+      public readonly int DbIndex;
+      public readonly int ModelIndex;
+
+      public ColumnIndexMapping(int dbIndex, int modelIndex)
+      {
+        DbIndex = dbIndex;
+        ModelIndex = modelIndex;
+      }
+    }
+
+    public void RegisterColumnMapping(int dbIndex, int modelIndex)
+    {
+      if (columnMappings is null)
+        columnMappings = new List<ColumnIndexMapping>(1);
+
+      columnMappings.Add(new ColumnIndexMapping(dbIndex, modelIndex));
+    }
+
+    public DataTableColumn GetColumn(int dbIndex)
+    {
+      int modelIndex = dbIndex-1;
+      if (Table is View view)
+        return view.ViewColumns[modelIndex];
+
+      var table = (Table)Table;
+      if (columnMappings is null)
+        return table.TableColumns[modelIndex];
+
+      var mapping = columnMappings.Where(item => item.DbIndex==dbIndex).FirstOrDefault();
+      if (mapping is not null)
+        return table.TableColumns[mapping.ModelIndex];
+
+      throw new ArgumentOutOfRangeException("dbIndex");
+    }
+
+    public ColumnResolver(DataTable table)
+    {
+      Table = table;
+    }
+  }
+}