Microsoft.Data.Sqlite: Target .NET Standard 2.0 again

src/Microsoft.Data.Sqlite.Core/Microsoft.Data.Sqlite.Core.csproj

@@ -15,7 +15,7 @@ Microsoft.Data.Sqlite.SqliteException
 Microsoft.Data.Sqlite.SqliteFactory
 Microsoft.Data.Sqlite.SqliteParameter
 Microsoft.Data.Sqlite.SqliteTransaction</Description>
-    <TargetFramework>net5.0</TargetFramework>
+    <TargetFrameworks>netstandard2.0;net5.0</TargetFrameworks>
     <MinClientVersion>3.6</MinClientVersion>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <CodeAnalysisRuleSet>Microsoft.Data.Sqlite.Core.ruleset</CodeAnalysisRuleSet>

src/Microsoft.Data.Sqlite.Core/SqliteTransaction.cs

@@ -114,15 +114,21 @@ public override void Rollback()
             RollbackInternal();
         }
 
+#if NET
         /// <inheritdoc />
         public override bool SupportsSavepoints => true;
+#endif
 
         /// <summary>
         /// Creates a savepoint in the transaction. This allows all commands that are executed after the savepoint was
         /// established to be rolled back, restoring the transaction state to what it was at the time of the savepoint.
         /// </summary>
         /// <param name="savepointName">The name of the savepoint to be created.</param>
+#if NET
         public override void Save(string savepointName)
+#else
+        public virtual void Save(string savepointName)
+#endif
         {
             if (savepointName is null)
             {
@@ -146,7 +152,11 @@ public override void Save(string savepointName)
         /// Rolls back all commands that were executed after the specified savepoint was established.
         /// </summary>
         /// <param name="savepointName">The name of the savepoint to roll back to.</param>
+#if NET
         public override void Rollback(string savepointName)
+#else
+        public virtual void Rollback(string savepointName)
+#endif
         {
             if (savepointName is null)
             {
@@ -171,7 +181,11 @@ public override void Rollback(string savepointName)
         /// reclaim some resources before the transaction ends.
         /// </summary>
         /// <param name="savepointName">The name of the savepoint to release.</param>
+#if NET
         public override void Release(string savepointName)
+#else
+        public virtual void Release(string savepointName)
+#endif
         {
             if (savepointName is null)
             {

src/Microsoft.Data.Sqlite.Core/SqliteValueReader.cs

@@ -240,7 +240,7 @@ public virtual string GetString(int ordinal)
                 return (T)(object)checked((ushort)GetInt64(ordinal));
             }
 
-            return (T)GetValue(ordinal);
+            return (T)GetValue(ordinal)!;
         }
 
         public virtual object? GetValue(int ordinal)

src/Microsoft.Data.Sqlite.Core/Utilities/AllowNullAttribute.cs

@@ -0,0 +1,14 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+#if !NET
+
+namespace System.Diagnostics.CodeAnalysis
+{
+    [AttributeUsage(AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property, Inherited = false)]
+    internal sealed class AllowNullAttribute : Attribute
+    {
+    }
+}
+
+#endif

src/Microsoft.Data.Sqlite/Microsoft.Data.Sqlite.csproj

@@ -15,7 +15,7 @@ Microsoft.Data.Sqlite.SqliteFactory
 Microsoft.Data.Sqlite.SqliteParameter
 Microsoft.Data.Sqlite.SqliteTransaction</Description>
     <IncludeBuildOutput>false</IncludeBuildOutput>
-    <TargetFramework>net5.0</TargetFramework>
+    <TargetFramework>netstandard2.0</TargetFramework>
     <MinClientVersion>3.6</MinClientVersion>
     <PackageTags>SQLite;Data;ADO.NET</PackageTags>
     <IncludeSymbols>false</IncludeSymbols>