fix #167: Ensure that a sql server database name that differs only by… (

#195)

grate.unittests/Generic/GenericDatabase.cs

@@ -87,6 +87,24 @@ public async Task Does_not_need_admin_connection_if_database_already_exists()
  Assert.DoesNotThrowAsync(() => migrator.Migrate());
  }
 
+ [Test]
+ public async Task Does_not_needlessly_apply_case_sensitive_database_name_checks_Issue_167()
+ {
+ // There's a bug where if the database name specified by the user differs from the actual database only by case then
+ // Grate currently attempts to create the database again, only for it to fail on the DBMS (Sql Server bug only).
+
+ var db = "CASEDATABASE";
+ await CreateDatabase(db);
+
+ // Check that the database has been created
+ IEnumerable<string> databasesBeforeMigration = await GetDatabases();
+ databasesBeforeMigration.Should().Contain(db);
+
+ await using var migrator = GetMigrator(GetConfiguration(db.ToLower(), true)); // ToLower is important here, this reproduces the bug in #167
+ // There should be no errors running the migration
+ Assert.DoesNotThrowAsync(() => migrator.Migrate());
+ }
+
  protected virtual async Task CreateDatabase(string db)
  {
  using (new TransactionScope(TransactionScopeOption.Suppress, TransactionScopeAsyncFlowOption.Enabled))

grate/Migration/SqlServerDatabase.cs

@@ -1,12 +1,16 @@
 using System;
 using System.Data.Common;
+using System.Linq;
 using System.Threading.Tasks;
 using System.Transactions;
+using Dapper;
 using grate.Configuration;
 using grate.Infrastructure;
 using Microsoft.Data.SqlClient;
 using Microsoft.Extensions.Logging;
 
+using static System.Data.CommandType;
+
 namespace grate.Migration;
 
 public class SqlServerDatabase : AnsiSqlDatabase
@@ -68,4 +72,28 @@ WITH NOUNLOAD
 
  Logger.LogInformation("Database {DbName} successfully restored from path {Path}.", DatabaseName, backupPath);
  }
+
+ public override async Task<bool> DatabaseExists()
+ {
+ // For Bug #167. Sql Server is causing issues when the database name passed in differs only in case from one already existing on the server.
+ // There's currently no point adding to ISyntax for this as all the other DBMS's would just be a NOP.
+
+ // This should also mean that a SQL server running a Case Sensitive collation _also_ works as expected
+ var sql = $"select name from sys.databases where [name] = '{DatabaseName}'";
+ try
+ {
+ await OpenConnection();
+ var results = await Connection.QueryAsync<string>(sql, commandType: Text);
+ return results.Any();
+ }
+ catch (DbException ex)
+ {
+ Logger.LogDebug(ex, "An unexpected error occurred performing the CheckDatabaseExists check: {ErrorMessage}", ex.Message);
+ return false; // base method also returns false on any DbException
+ }
+ finally
+ {
+ await CloseConnection();
+ }
+ }
 }