add IsRelational extension for DatabaseFacade

src/EFCore.Relational/Extensions/RelationalDatabaseFacadeExtensions.cs

@@ -604,6 +604,19 @@ public static void SetCommandTimeout([NotNull] this DatabaseFacade databaseFacad
         public static string GenerateCreateScript([NotNull] this DatabaseFacade databaseFacade)
             => databaseFacade.GetRelationalService<IRelationalDatabaseCreator>().GenerateCreateScript();
 
+        /// <summary>
+        ///     <para>
+        ///         Returns true if the database provider currently in use is a relational database.
+        ///     </para>
+        /// </summary>
+        /// <param name="databaseFacade"> The facade from <see cref="DbContext.Database" />. </param>
+        /// <returns> True if a relational database provider is being used; false otherwise. </returns>
+        public static bool IsRelational([NotNull] this DatabaseFacade databaseFacade)
+        {
+            var dependencies = ((IDatabaseFacadeDependenciesAccessor)databaseFacade).Dependencies;
+            return dependencies is IRelationalDatabaseFacadeDependencies;
+        }
+
         private static IRelationalDatabaseFacadeDependencies GetFacadeDependencies(DatabaseFacade databaseFacade)
         {
             var dependencies = ((IDatabaseFacadeDependenciesAccessor)databaseFacade).Dependencies;

test/EFCore.Relational.Tests/RelationalDatabaseFacadeExtensionsTest.cs

@@ -23,6 +23,15 @@ namespace Microsoft.EntityFrameworkCore
 {
     public class RelationalDatabaseFacadeExtensionsTest
     {
+        [ConditionalFact]
+        public void IsRelational_returns_if_relational()
+        {
+            var dbConnection = new FakeDbConnection("A=B");
+            var context = RelationalTestHelpers.Instance.CreateContext();
+            Assert.True(context.Database.IsRelational());
+        }
+
+
         [ConditionalFact]
         public void GetDbConnection_returns_the_current_connection()
         {