- 优化 MaxLength 功能，并且增加 [Column(StringLength = 100)] 同等的特性功能；

FreeSql.DbContext/FreeSql.DbContext.xml

@@ -110,13 +110,6 @@
             清空状态数据
             </summary>
         </member>
-        <member name="M:FreeSql.DbSet`1.RemoveAsync(System.Linq.Expressions.Expression{System.Func{`0,System.Boolean}})">
-            <summary>
-            根据 lambda 条件删除数据
-            </summary>
-            <param name="predicate"></param>
-            <returns></returns>
-        </member>
         <member name="M:FreeSql.DbSet`1.Add(`0)">
             <summary>
             添加

FreeSql/DataAnnotations/ColumnAttribute.cs

@@ -17,7 +17,7 @@ namespace FreeSql.DataAnnotations
         public string OldName { get; set; }
         /// <summary>
         /// 数据库类型，如： varchar(255) <para></para>
-        /// 字符串长度，可使用特性 MaxLength(255)
+        /// 字符串长度，可使用特性 [MaxLength(255)]
         /// </summary>
         public string DbType { get; set; }
 
@@ -76,5 +76,26 @@ namespace FreeSql.DataAnnotations
         /// 标记属性为数据库服务器时间(utc/local)，在插入的时候使用类似 getdate() 执行
         /// </summary>
         public DateTimeKind ServerTime { get; set; }
+
+        internal int? _StringLength;
+        /// <summary>
+        /// 设置长度，针对 string 类型避免 DbType 的繁琐设置<para></para>
+        /// 提示：也可以使用 [MaxLength(100)]<para></para>
+        /// ---<para></para>
+        /// StringLength = 100 时，对应 DbType：<para></para>
+        /// MySql -> varchar(100)<para></para>
+        /// SqlServer -> nvarchar(100)<para></para>
+        /// PostgreSQL -> varchar(100)<para></para>
+        /// Oracle -> nvarchar2(100)<para></para>
+        /// Sqlite -> nvarchar(100)<para></para>
+        /// ---<para></para>
+        /// StringLength = -1 时，对应 DbType：<para></para>
+        /// MySql -> text<para></para>
+        /// SqlServer -> nvarchar(max)<para></para>
+        /// PostgreSQL -> text<para></para>
+        /// Oracle -> nvarchar2(4000)<para></para>
+        /// Sqlite -> text<para></para>
+        /// </summary>
+        public int StringLength { get => _StringLength ?? 0; set => _StringLength = value; }
     }
 }

FreeSql/DataAnnotations/ColumnFluent.cs

@@ -135,5 +135,28 @@ namespace FreeSql.DataAnnotations
             _column.ServerTime = value;
             return this;
         }
+
+        /// <summary>
+        /// 设置长度，针对 string 类型避免 DbType 的繁琐设置<para></para>
+        /// ---<para></para>
+        /// StringLength = 100 时，对应 DbType：<para></para>
+        /// MySql -> varchar(100)<para></para>
+        /// SqlServer -> nvarchar(100)<para></para>
+        /// PostgreSQL -> varchar(100)<para></para>
+        /// Oracle -> nvarchar2(100)<para></para>
+        /// Sqlite -> nvarchar(100)<para></para>
+        /// ---<para></para>
+        /// StringLength = -1 时，对应 DbType：<para></para>
+        /// MySql -> text<para></para>
+        /// SqlServer -> nvarchar(max)<para></para>
+        /// PostgreSQL -> text<para></para>
+        /// Oracle -> nvarchar2(4000)<para></para>
+        /// Sqlite -> text<para></para>
+        /// </summary>
+        public ColumnFluent StringLength(int value)
+        {
+            _column.StringLength = value;
+            return this;
+        }
     }
 }

FreeSql/FreeSql.xml

@@ -17,7 +17,7 @@
         <member name="P:FreeSql.DataAnnotations.ColumnAttribute.DbType">
             <summary>
             数据库类型，如： varchar(255) <para></para>
-            字符串长度，可使用特性 MaxLength(255)
+            字符串长度，可使用特性 [MaxLength(255)]
             </summary>
         </member>
         <member name="P:FreeSql.DataAnnotations.ColumnAttribute.IsPrimary">
@@ -78,6 +78,26 @@
             标记属性为数据库服务器时间(utc/local)，在插入的时候使用类似 getdate() 执行
             </summary>
         </member>
+        <member name="P:FreeSql.DataAnnotations.ColumnAttribute.StringLength">
+            <summary>
+            设置长度，针对 string 类型避免 DbType 的繁琐设置<para></para>
+            提示：也可以使用 [MaxLength(100)]<para></para>
+            ---<para></para>
+            StringLength = 100 时，对应 DbType：<para></para>
+            MySql -> varchar(100)<para></para>
+            SqlServer -> nvarchar(100)<para></para>
+            PostgreSQL -> varchar(100)<para></para>
+            Oracle -> nvarchar2(100)<para></para>
+            Sqlite -> nvarchar(100)<para></para>
+            ---<para></para>
+            StringLength = -1 时，对应 DbType：<para></para>
+            MySql -> text<para></para>
+            SqlServer -> nvarchar(max)<para></para>
+            PostgreSQL -> text<para></para>
+            Oracle -> nvarchar2(4000)<para></para>
+            Sqlite -> text<para></para>
+            </summary>
+        </member>
         <member name="M:FreeSql.DataAnnotations.ColumnFluent.Name(System.String)">
             <summary>
             数据库列名
@@ -159,6 +179,25 @@
             <param name="value"></param>
             <returns></returns>
         </member>
+        <member name="M:FreeSql.DataAnnotations.ColumnFluent.StringLength(System.Int32)">
+            <summary>
+            设置长度，针对 string 类型避免 DbType 的繁琐设置<para></para>
+            ---<para></para>
+            StringLength = 100 时，对应 DbType：<para></para>
+            MySql -> varchar(100)<para></para>
+            SqlServer -> nvarchar(100)<para></para>
+            PostgreSQL -> varchar(100)<para></para>
+            Oracle -> nvarchar2(100)<para></para>
+            Sqlite -> nvarchar(100)<para></para>
+            ---<para></para>
+            StringLength = -1 时，对应 DbType：<para></para>
+            MySql -> text<para></para>
+            SqlServer -> nvarchar(max)<para></para>
+            PostgreSQL -> text<para></para>
+            Oracle -> nvarchar2(4000)<para></para>
+            Sqlite -> text<para></para>
+            </summary>
+        </member>
         <member name="T:FreeSql.DataAnnotations.ExpressionCallAttribute">
             <summary>
             自定义表达式函数解析<para></para>

FreeSql/FreeSqlBuilder.cs

@@ -263,34 +263,9 @@ namespace FreeSql
                     if (maxlenAttr != null)
                     {
                         var lenProp = maxlenAttr.GetType().GetProperties().Where(a => a.PropertyType.IsNumberType()).FirstOrDefault();
-                        if (lenProp != null && int.TryParse(string.Concat(lenProp.GetValue(maxlenAttr, null)), out var tryval))
+                        if (lenProp != null && int.TryParse(string.Concat(lenProp.GetValue(maxlenAttr, null)), out var tryval) && tryval != 0)
                         {
-                            if (tryval != 0)
+                            e.ModifyResult.StringLength = tryval;
-                            {
-                                switch (ret.Ado.DataType)
-                                {
-                                    case DataType.MySql:
-                                    case DataType.OdbcMySql:
-                                        e.ModifyResult.DbType = tryval > 0 ? $"varchar({tryval})" : "text";
-                                        break;
-                                    case DataType.SqlServer:
-                                    case DataType.OdbcSqlServer:
-                                        e.ModifyResult.DbType = tryval > 0 ? $"nvarchar({tryval})" : "nvarchar(max)";
-                                        break;
-                                    case DataType.PostgreSQL:
-                                    case DataType.OdbcPostgreSQL:
-                                        e.ModifyResult.DbType = tryval > 0 ? $"varchar({tryval})" : "text";
-                                        break;
-                                    case DataType.Oracle:
-                                    case DataType.OdbcOracle:
-                                        e.ModifyResult.DbType = tryval > 0 ? $"nvarchar2({tryval})" : "nvarchar2(4000)";
-                                        break;
-                                    case DataType.Sqlite:
-                                        e.ModifyResult.DbType = tryval > 0 ? $"nvarchar({tryval})" : "text";
-                                        break;
-
-                                }
-                            }
                         }
                     }
                 });

FreeSql/Internal/CommonUtils.cs

@@ -129,6 +129,7 @@ namespace FreeSql.Internal
                 if (trycol._CanInsert != null) attr._CanInsert = trycol.CanInsert;
                 if (trycol._CanUpdate != null) attr._CanUpdate = trycol.CanUpdate;
                 if (trycol.ServerTime != DateTimeKind.Unspecified) attr.ServerTime = trycol.ServerTime;
+                if (trycol._StringLength != null) attr.StringLength = trycol.StringLength;
             }
             var attrs = proto.GetCustomAttributes(typeof(ColumnAttribute), false);
             foreach (var tryattrobj in attrs)
@@ -148,6 +149,7 @@ namespace FreeSql.Internal
                 if (tryattr._CanInsert != null) attr._CanInsert = tryattr.CanInsert;
                 if (tryattr._CanUpdate != null) attr._CanUpdate = tryattr.CanUpdate;
                 if (tryattr.ServerTime != DateTimeKind.Unspecified) attr.ServerTime = tryattr.ServerTime;
+                if (tryattr._StringLength != null) attr.StringLength = tryattr.StringLength;
             }
             ColumnAttribute ret = null;
             if (!string.IsNullOrEmpty(attr.Name)) ret = attr;
@@ -163,6 +165,7 @@ namespace FreeSql.Internal
             if (attr._CanInsert != null) ret = attr;
             if (attr._CanUpdate != null) ret = attr;
             if (attr.ServerTime != DateTimeKind.Unspecified) ret = attr;
+            if (attr._StringLength != null) ret = attr;
             if (ret != null && ret.MapType == null) ret.MapType = proto.PropertyType;
             return ret;
         }

FreeSql/Internal/UtilsExpressionTree.cs

@@ -194,6 +194,38 @@ namespace FreeSql.Internal
                     col.DbDefaultValue = colattr.ServerTime == DateTimeKind.Local ? common.Now : common.NowUtc;
                     col.DbInsertValue = colattr.ServerTime == DateTimeKind.Local ? common.Now : common.NowUtc;
                 }
+                if (colattr.MapType == typeof(string) && colattr.StringLength != 0)
+                {
+                    int strlen = colattr.StringLength;
+                    var charPatten = @"(CHAR|CHAR2|CHARACTER)\s*(\([^\)]*\))?";
+                    switch (common._orm.Ado.DataType)
+                    {
+                        case DataType.MySql:
+                        case DataType.OdbcMySql:
+                            if (strlen < 0) colattr.DbType = "text";
+                            else colattr.DbType = Regex.Replace(colattr.DbType, charPatten, $"$1({strlen})");
+                            break;
+                        case DataType.SqlServer:
+                        case DataType.OdbcSqlServer:
+                            if (strlen < 0) colattr.DbType = Regex.Replace(colattr.DbType, charPatten, $"$1(MAX)");
+                            else colattr.DbType = Regex.Replace(colattr.DbType, charPatten, $"$1({strlen})");
+                            break;
+                        case DataType.PostgreSQL:
+                        case DataType.OdbcPostgreSQL:
+                            if (strlen < 0) colattr.DbType = "text";
+                            else colattr.DbType = Regex.Replace(colattr.DbType, charPatten, $"$1({strlen})");
+                            break;
+                        case DataType.Oracle:
+                        case DataType.OdbcOracle:
+                            if (strlen < 0) colattr.DbType = Regex.Replace(colattr.DbType, charPatten, $"$1(4000)");
+                            else colattr.DbType = Regex.Replace(colattr.DbType, charPatten, $"$1({strlen})");
+                            break;
+                        case DataType.Sqlite:
+                            if (strlen < 0) colattr.DbType = "text";
+                            else colattr.DbType = Regex.Replace(colattr.DbType, charPatten, $"$1({strlen})");
+                            break;
+                    }
+                }
 
                 if (trytb.Columns.ContainsKey(colattr.Name)) throw new Exception($"ColumnAttribute.Name {colattr.Name} 重复存在，请检查（注意：不区分大小写）");
                 if (trytb.ColumnsByCs.ContainsKey(p.Name)) throw new Exception($"属性名 {p.Name} 重复存在，请检查（注意：不区分大小写）");