Refactor RowCount into DialectProvider so Oracle can have custom impl

Author: mythz

src/ServiceStack.OrmLite.Oracle/OracleOrmLiteDialectProvider.cs

@@ -1095,5 +1095,10 @@ public override string ToSelectStatement(ModelDefinition modelDef,
 
             return sb.ToString();
         }
+
+        public override string ToRowCountStatement(string innerSql)
+        {
+            return "SELECT COUNT(*) FROM ({0})".Fmt(innerSql);
+        }
     }
 }

src/ServiceStack.OrmLite/Expressions/ReadExpressionCommandExtensions.cs

@@ -118,13 +118,12 @@ internal static long GetCount(this IDbCommand dbCmd, string sql)
 
         internal static long RowCount<T>(this IDbCommand dbCmd, SqlExpression<T> expression)
         {
-            var sql = "SELECT COUNT(*) FROM ({0})".Fmt(expression.ToSelectStatement());
-            return dbCmd.Scalar<long>(sql);
+            return dbCmd.Scalar<long>(dbCmd.GetDialectProvider().ToRowCountStatement(expression.ToSelectStatement()));
         }
 
         internal static long RowCount(this IDbCommand dbCmd, string sql)
         {
-            return dbCmd.Scalar<long>("SELECT COUNT(*) FROM ({0})".Fmt(sql));
+            return dbCmd.Scalar<long>(dbCmd.GetDialectProvider().ToRowCountStatement(sql));
         }
 
         internal static List<T> LoadSelect<T>(this IDbCommand dbCmd, Func<SqlExpression<T>, SqlExpression<T>> expression)

src/ServiceStack.OrmLite/IOrmLiteDialectProvider.cs

@@ -163,5 +163,6 @@ string ToCreateIndexStatement<T>(Expression<Func<T, object>> field,
         Task<long> InsertAndGetLastInsertIdAsync<T>(IDbCommand dbCmd, CancellationToken token);
 
         string GetLoadChildrenSubSelect<From>(ModelDefinition modelDef, SqlExpression<From> expr);
+        string ToRowCountStatement(string innerSql);
     }
 }

src/ServiceStack.OrmLite/OrmLiteDialectProviderBase.cs

@@ -1399,6 +1399,11 @@ public virtual string GetLoadChildrenSubSelect<From>(ModelDefinition modelDef, S
             return subSql;
         }
 
+        public virtual string ToRowCountStatement(string innerSql)
+        {
+            return "SELECT COUNT(*) FROM ({0}) AS COUNT".Fmt(innerSql);
+        }
+
         //Async API's, should be overrided by Dialect Providers to use .ConfigureAwait(false)
         //Default impl below uses TaskAwaiter shim in async.cs