Add IRelationalDatabaseCreator.HasTables and make the implementation …

…public

Fixes #15997

src/EFCore.Relational/Storage/IRelationalDatabaseCreator.cs

@@ -46,6 +46,24 @@ public interface IRelationalDatabaseCreator : IDatabaseCreator
         /// </returns>
         Task<bool> ExistsAsync(CancellationToken cancellationToken = default);
 
+        /// <summary>
+        ///     Determines whether the database contains any tables. No attempt is made to determine if
+        ///     tables belong to the current model or not.
+        /// </summary>
+        /// <returns> A value indicating whether any tables are present in the database. </returns>
+        bool HasTables();
+
+        /// <summary>
+        ///     Asynchronously determines whether the database contains any tables. No attempt is made to determine if
+        ///     tables belong to the current model or not.
+        /// </summary>
+        /// <param name="cancellationToken">A <see cref="CancellationToken" /> to observe while waiting for the task to complete.</param>
+        /// <returns>
+        ///     A task that represents the asynchronous operation. The task result contains
+        ///     a value indicating whether any tables are present in the database.
+        /// </returns>
+        Task<bool> HasTablesAsync(CancellationToken cancellationToken = default);
+
         /// <summary>
         ///     Creates the physical database. Does not attempt to populate it with any schema.
         /// </summary>

src/EFCore.Relational/Storage/RelationalDatabaseCreator.cs

@@ -145,7 +145,7 @@ protected virtual IReadOnlyList<MigrationCommand> GetCreateTablesCommands()
         ///     tables belong to the current model or not.
         /// </summary>
         /// <returns> A value indicating whether any tables are present in the database. </returns>
-        protected abstract bool HasTables();
+        public abstract bool HasTables();
 
         /// <summary>
         ///     Asynchronously determines whether the database contains any tables. No attempt is made to determine if
@@ -156,7 +156,7 @@ protected virtual IReadOnlyList<MigrationCommand> GetCreateTablesCommands()
         ///     A task that represents the asynchronous operation. The task result contains
         ///     a value indicating whether any tables are present in the database.
         /// </returns>
-        protected virtual Task<bool> HasTablesAsync(CancellationToken cancellationToken = default)
+        public virtual Task<bool> HasTablesAsync(CancellationToken cancellationToken = default)
         {
             cancellationToken.ThrowIfCancellationRequested();
 

src/EFCore.SqlServer/Storage/Internal/SqlServerDatabaseCreator.cs

@@ -111,7 +111,7 @@ await Dependencies.MigrationCommandExecutor
         ///     any release. You should only use it directly in your code with extreme caution and knowing that
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
-        protected override bool HasTables()
+        public override bool HasTables()
             => Dependencies.ExecutionStrategyFactory
                 .Create()
                 .Execute(
@@ -128,7 +128,7 @@ protected override bool HasTables()
         ///     any release. You should only use it directly in your code with extreme caution and knowing that
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
-        protected override Task<bool> HasTablesAsync(CancellationToken cancellationToken = default)
+        public override Task<bool> HasTablesAsync(CancellationToken cancellationToken = default)
             => Dependencies.ExecutionStrategyFactory.Create().ExecuteAsync(
                 _connection,
                 async (connection, ct) => (int)await CreateHasTablesCommand()

src/EFCore.Sqlite.Core/Storage/Internal/SqliteDatabaseCreator.cs

@@ -92,7 +92,7 @@ public override bool Exists()
         ///     any release. You should only use it directly in your code with extreme caution and knowing that
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
-        protected override bool HasTables()
+        public override bool HasTables()
         {
             var count = (long)_rawSqlCommandBuilder
                 .Build("SELECT COUNT(*) FROM \"sqlite_master\" WHERE \"type\" = 'table' AND \"rootpage\" IS NOT NULL;")

test/EFCore.Relational.Tests/TestUtilities/FakeProvider/FakeRelationalDatabaseCreator.cs

@@ -24,6 +24,8 @@ public class FakeRelationalDatabaseCreator : IRelationalDatabaseCreator
         public Task<bool> CanConnectAsync(CancellationToken cancellationToken = default) => throw new NotImplementedException();
         public bool Exists() => throw new NotImplementedException();
         public Task<bool> ExistsAsync(CancellationToken cancellationToken = new CancellationToken()) => throw new NotImplementedException();
+        public bool HasTables() => throw new NotImplementedException();
+        public Task<bool> HasTablesAsync(CancellationToken cancellationToken = default) => throw new NotImplementedException();
         public void Create() => throw new NotImplementedException();
         public Task CreateAsync(CancellationToken cancellationToken = new CancellationToken()) => throw new NotImplementedException();
         public void Delete() => throw new NotImplementedException();

test/EFCore.Sqlite.FunctionalTests/SqliteDatabaseCreatorTest.cs

@@ -34,6 +34,35 @@ public async Task Exists_returns_false_when_database_doesnt_exist(bool async, bo
             }
         }
 
+        [ConditionalTheory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public async Task HasTables_returns_false_when_database_is_empty(bool async)
+        {
+            using (var testStore = SqliteTestStore.GetOrCreateInitialized("Empty"))
+            {
+                var context = CreateContext(testStore.ConnectionString);
+
+                var creator = context.GetService<IRelationalDatabaseCreator>();
+                Assert.False(async ? await creator.HasTablesAsync() : creator.HasTables());
+            }
+        }
+
+        [ConditionalTheory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public async Task HasTables_returns_true_when_database_is_not_empty(bool async)
+        {
+            using (var testStore = SqliteTestStore.GetOrCreateInitialized($"HasATable{(async ? 'A' : 'S')}"))
+            {
+                var context = CreateContext(testStore.ConnectionString);
+                context.Database.ExecuteSqlRaw("CREATE TABLE Dummy (Foo INTEGER)");
+
+                var creator = context.GetService<IRelationalDatabaseCreator>();
+                Assert.True(async ? await creator.HasTablesAsync() : creator.HasTables());
+            }
+        }
+
         [ConditionalTheory]
         [InlineData(false, false)]
         [InlineData(true, false)]