- 增加 ISelect.ForUpdate 排他更新锁（根据数据库类型的规则，见代码注释）；

- 完善 SqlServer WithLock 功能，组合多种使用 | 枚举相联；

FreeSql/FreeSql.xml

@@ -1154,6 +1154,20 @@
             <param name="name">零个或多个过滤器名字</param>
             <returns></returns>
         </member>
+        <member name="M:FreeSql.ISelect0`2.ForUpdate(System.Boolean)">
+            <summary>
+            排他更新锁<para></para>
+            注意：务必在开启事务后使用该功能<para></para>
+            MySql: for update<para></para>
+            SqlServer: With(UpdLock, RowLock, NoWait)<para></para>
+            PostgreSQL: for update nowait<para></para>
+            Oracle: for update nowait<para></para>
+            Sqlite: 无效果<para></para>
+            达梦: for update nowait
+            </summary>
+            <param name="nowait">noawait</param>
+            <returns></returns>
+        </member>
         <member name="M:FreeSql.ISelect0`2.GroupBy(System.String,System.Object)">
             <summary>
             按原生sql语法分组，GroupBy("concat(name, ?cc)", new { cc = 1 })
@@ -1956,7 +1970,7 @@
         </member>
         <member name="M:FreeSql.IAdo.Transaction(System.Action)">
             <summary>
-            开启事务（不支持异步），60秒未执行完将自动提交
+            开启事务（不支持异步），60秒未执行完成（可能）被其他线程事务自动提交
             </summary>
             <param name="handler">事务体 () => {}</param>
         </member>
@@ -1964,7 +1978,7 @@
             <summary>
             开启事务（不支持异步）
             </summary>
-            <param name="timeout">超时，未执行完将自动提交</param>
+            <param name="timeout">超时，未执行完成（可能）被其他线程事务自动提交</param>
             <param name="handler">事务体 () => {}</param>
         </member>
         <member name="M:FreeSql.IAdo.Transaction(System.Data.IsolationLevel,System.TimeSpan,System.Action)">
@@ -1973,7 +1987,7 @@
             </summary>
             <param name="isolationLevel"></param>
             <param name="handler">事务体 () => {}</param>
-            <param name="timeout">超时，未执行完将自动提交</param>
+            <param name="timeout">超时，未执行完成（可能）被其他线程事务自动提交</param>
         </member>
         <member name="P:FreeSql.IAdo.TransactionCurrentThread">
             <summary>
@@ -2974,7 +2988,7 @@
         </member>
         <member name="M:IFreeSql.Transaction(System.Action)">
             <summary>
-            开启事务（不支持异步），60秒未执行完将自动提交
+            开启事务（不支持异步），60秒未执行完成（可能）被其他线程事务自动提交
             </summary>
             <param name="handler">事务体 () => {}</param>
         </member>
@@ -2982,7 +2996,7 @@
             <summary>
             开启事务（不支持异步）
             </summary>
-            <param name="timeout">超时，未执行完将自动提交</param>
+            <param name="timeout">超时，未执行完成（可能）被其他线程事务自动提交</param>
             <param name="handler">事务体 () => {}</param>
         </member>
         <member name="M:IFreeSql.Transaction(System.Data.IsolationLevel,System.TimeSpan,System.Action)">
@@ -2991,7 +3005,7 @@
             </summary>
             <param name="isolationLevel"></param>
             <param name="handler">事务体 () => {}</param>
-            <param name="timeout">超时，未执行完将自动提交</param>
+            <param name="timeout">超时，未执行完成（可能）被其他线程事务自动提交</param>
         </member>
         <member name="P:IFreeSql.Ado">
             <summary>

FreeSql/Interface/Curd/ISelect/ISelect0.cs

@@ -250,6 +250,20 @@ namespace FreeSql
         /// <returns></returns>
         TSelect DisableGlobalFilter(params string[] name);
 
+        /// <summary>
+        /// 排他更新锁<para></para>
+        /// 注意：务必在开启事务后使用该功能<para></para>
+        /// MySql: for update<para></para>
+        /// SqlServer: With(UpdLock, RowLock, NoWait)<para></para>
+        /// PostgreSQL: for update nowait<para></para>
+        /// Oracle: for update nowait<para></para>
+        /// Sqlite: 无效果<para></para>
+        /// 达梦: for update nowait
+        /// </summary>
+        /// <param name="nowait">noawait</param>
+        /// <returns></returns>
+        TSelect ForUpdate(bool nowait = false);
+
         /// <summary>
         /// 按原生sql语法分组，GroupBy("concat(name, ?cc)", new { cc = 1 })
         /// </summary>

FreeSql/Interface/IAdo.cs

@@ -34,14 +34,14 @@ namespace FreeSql
 
         #region 事务
         /// <summary>
-        /// 开启事务（不支持异步），60秒未执行完将自动提交
+        /// 开启事务（不支持异步），60秒未执行完成（可能）被其他线程事务自动提交
         /// </summary>
         /// <param name="handler">事务体 () => {}</param>
         void Transaction(Action handler);
         /// <summary>
         /// 开启事务（不支持异步）
         /// </summary>
-        /// <param name="timeout">超时，未执行完将自动提交</param>
+        /// <param name="timeout">超时，未执行完成（可能）被其他线程事务自动提交</param>
         /// <param name="handler">事务体 () => {}</param>
         void Transaction(TimeSpan timeout, Action handler);
         /// <summary>
@@ -49,7 +49,7 @@ namespace FreeSql
         /// </summary>
         /// <param name="isolationLevel"></param>
         /// <param name="handler">事务体 () => {}</param>
-        /// <param name="timeout">超时，未执行完将自动提交</param>
+        /// <param name="timeout">超时，未执行完成（可能）被其他线程事务自动提交</param>
         void Transaction(IsolationLevel isolationLevel, TimeSpan timeout, Action handler);
         /// <summary>
         /// 当前线程的事务

FreeSql/Interface/IFreeSql.cs

@@ -87,14 +87,14 @@ public interface IFreeSql : IDisposable
     IDelete<T1> Delete<T1>(object dywhere) where T1 : class;
 
     /// <summary>
-    /// 开启事务（不支持异步），60秒未执行完将自动提交
+    /// 开启事务（不支持异步），60秒未执行完成（可能）被其他线程事务自动提交
     /// </summary>
     /// <param name="handler">事务体 () => {}</param>
     void Transaction(Action handler);
     /// <summary>
     /// 开启事务（不支持异步）
     /// </summary>
-    /// <param name="timeout">超时，未执行完将自动提交</param>
+    /// <param name="timeout">超时，未执行完成（可能）被其他线程事务自动提交</param>
     /// <param name="handler">事务体 () => {}</param>
     void Transaction(TimeSpan timeout, Action handler);
     /// <summary>
@@ -102,7 +102,7 @@ public interface IFreeSql : IDisposable
     /// </summary>
     /// <param name="isolationLevel"></param>
     /// <param name="handler">事务体 () => {}</param>
-    /// <param name="timeout">超时，未执行完将自动提交</param>
+    /// <param name="timeout">超时，未执行完成（可能）被其他线程事务自动提交</param>
     void Transaction(IsolationLevel isolationLevel, TimeSpan timeout, Action handler);
 
     /// <summary>

FreeSql/Internal/CommonProvider/SelectProvider/Select0Provider.cs

@@ -26,6 +26,7 @@ namespace FreeSql.Internal.CommonProvider
         protected List<SelectTableInfo> _tables = new List<SelectTableInfo>();
         protected List<Func<Type, string, string>> _tableRules = new List<Func<Type, string, string>>();
         protected Func<Type, string, string> _aliasRule;
+        protected string _tosqlAppendContent;
         protected StringBuilder _join = new StringBuilder();
         protected IFreeSql _orm;
         protected CommonUtils _commonUtils;
@@ -990,6 +991,36 @@ namespace FreeSql.Internal.CommonProvider
             }
             return this as TSelect;
         }
+        public TSelect ForUpdate(bool noawait = false)
+        {
+            if (_transaction == null && _orm.Ado.TransactionCurrentThread == null)
+                throw new Exception("安全起见，请务必在事务开启之后，再使用 ForUpdate");
+            switch (_orm.Ado.DataType)
+            {
+                case DataType.MySql:
+                case DataType.OdbcMySql:
+                    _tosqlAppendContent = " for update";
+                    break;
+                case DataType.SqlServer:
+                case DataType.OdbcSqlServer:
+                    _aliasRule = (_, old) => $"{old} With(UpdLock, RowLock{(noawait ? ", NoWait" : "")})";
+                    break;
+                case DataType.PostgreSQL:
+                case DataType.OdbcPostgreSQL:
+                    _tosqlAppendContent = $" for update{(noawait ? " nowait" : "")}";
+                    break;
+                case DataType.Oracle:
+                case DataType.OdbcOracle:
+                    _tosqlAppendContent = $" for update{(noawait ? " nowait" : "")}";
+                    break;
+                case DataType.Sqlite:
+                    break;
+                case DataType.OdbcDameng:
+                    _tosqlAppendContent = $" for update{(noawait ? " nowait" : "")}";
+                    break;
+            }
+            return this as TSelect;
+        }
         #region common
 
         protected TMember InternalAvg<TMember>(Expression exp) => this.ToList<TMember>($"avg({_commonExpression.ExpressionSelectColumn_MemberAccess(_tables, null, SelectTableInfoType.From, exp, true, null)})").FirstOrDefault();

FreeSql/Internal/CommonProvider/SelectProvider/Select1Provider.cs

@@ -636,13 +636,18 @@ namespace FreeSql.Internal.CommonProvider
                 foreach (var item in list)
                     setListValue(item, null);
 
-                var subSelect = _orm.Select<TNavigate>().DisableGlobalFilter().WithConnection(_connection).WithTransaction(_transaction).TrackToList(_trackToList) as Select1Provider<TNavigate>;
+                var subSelect = _orm.Select<TNavigate>()
+                    .DisableGlobalFilter()
+                    .WithConnection(_connection)
+                    .WithTransaction(_transaction)
+                    .TrackToList(_trackToList) as Select1Provider<TNavigate>;
                 if (_tableRules?.Any() == true)
                     foreach (var tr in _tableRules) subSelect.AsTable(tr);
 
                 if (_whereCascadeExpression.Any())
                     subSelect._whereCascadeExpression.AddRange(_whereCascadeExpression.ToArray());
 
+                //subSelect._aliasRule = _aliasRule; //把 SqlServer 查询锁传递下去
                 then?.Invoke(subSelect);
                 var subSelectT1Alias = subSelect._tables[0].Alias;
                 var oldWhere = subSelect._where.ToString();