轻量级表达式树解析框架Faller

2019-11-14 16:33:21

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有话说

之前我写了3篇关于表达式树解析的文章

干货!表达式树解析"框架"(1)

干货!表达式树解析"框架"(2)

干货!表达式树解析"框架"(3)

这3篇文章更多的是说明一种方法,一种思路,而代码比较少

在发出来之后也有些朋友互加了好友一起讨论

在经过一些时间的修改和优化后,就有了现在这个框架

目前这个框架实现了SqlServer和Oracle的解释

其他数据库1来是不熟2来没时间3来我更希望大家可以使用这个框架自己动手实现一个数据库的解析,非常有意思

特色

首先是这个框架的名字 : Faller 中译伐木工,但我喜欢叫他 "砍树人",因为他把"表达式树"这颗大树砍成一片一片的小块然后转化成sql语句

轻量 : 不仅仅是代码轻量,重新实现对一个新的数据库支持也很轻量,只需要实现ISaw接口,或继承BaseSaw实现少量方法即可
如 :

Where(u => u.Birthday.Day == 1);                   //EXTRACT(DAY FROM a.BIRTHDAY) = 1Where(u => u.Name.Trim() == "");                    //ltrim(rtrim(a.NAME)) = :auto_p0Where(u => string.IsNullOrEmpty(u.Name));      //a.NAME IS NULL OR a.NAME == ''

灵活 : 在轻量的基础上尽量做到了灵活,可以非常方便的解析各种C#的方法
对 DateTime.Now 的处理 :
如 : Where(u => u.Birthday < DateTime.Now) //可以被解析为 BIRTHDAY < SYSDATE 或 BIRTHDAY < GETDATE()
自由的 SqlExPR : 有时候我们不得不使用Sql来表示某个数据库特有的数据
如 : Set<User>(() => new User{ ID = (SqlExpr)"seq_user.nextval"}) //解析后得到 ID = seq_user.nextval
使用方便 : 可以非常方便的嵌入到现已有的项目中,主要根据自己项目的需求重新实现ISaw即可

使用方式

void Where(string expected, Expression<Func<User, bool>> expr){    var parse = Faller.Create(expr);     //通过LambdaExpression创建Faller对象    var sql = parse.ToWhere(OracleSaw.Instance);//使用特定的ISaw来格式化Sql语句    //parse.Parameters  //解析过程中产生的参数    Assert.AreEqual(expected, sql);}

项目结构

Faller : 解析框架主要功能类,不可重写,实现 IFaller 接口,主要方法有 public static IFaller Create(LambdaExpression expr)
ISaw : 定义一组方法，它支持自定义Sql语句的格式。Faller负责拆解 LambdaExpression ,然后把特定的对象交给ISaw处理返回sql语句
SawDust : 解析结果。当一个方法在Faller中无法被解释时候,Faller会把方法所用到的对象和参数都构造成为SawDust 并交给ISaw处理,SawDust 由DustType Type和Object Value组成
DustType : 表示解释结果类型的枚举 ,它的值有 Undefined, Sql, Object, Number, Array, Boolean, DateTime, Binary, String
SqlExpr : Sql表达式,它只能由String强转获得; 它可以隐式转换为所有基础对象,但只能在表达式树中使用, 如
Where<User>(u => (SqlExpr)"@@identity" == 5); //@@identity = 5

对象定义

// 轻量级表达式树解析器 接口 public interface IFaller{    // 将表达式转为Where语句,不包含Where关键字    //saw: 自定义输出Sql语句的格式的对象    string ToWhere(ISaw saw);    // 将表达式转为OrderBy语句,不包含OrderBy关键字    //saw: 自定义输出Sql语句的格式的对象    //asc: 正序或倒序标识    string ToOrderBy(ISaw saw, bool asc);    // 将表达式转为Update中Set语句,不包含Set关键字    //saw: 自定义输出Sql语句的格式的对象    string ToSets(ISaw saw);    // 将表达式转为select语句中的列或列集合的Sql语句    //saw: 自定义输出Sql语句的格式的对象    string ToSelectColumns(ISaw saw);    // 将表达式转为值或值集合的sql语句    //saw: 自定义输出Sql语句的格式的对象    string ToValues(ISaw saw);    // 将表达式转为值或值集合的sql语句    //saw: 自定义输出Sql语句的格式的对象    string ToValues(ISaw saw, Func<string, string> replace);    // 将表达式转为列集合和值集合2个sql语句,可用于拼装insert语句    //saw: 自定义输出Sql语句的格式的对象    KeyValuePair<string, string> ToColumnsAndValues(ISaw saw);    // 转换Sql语句过程中产生的参数    ICollection<DbParameter> Parameters { get; }}

IFaller

    /// <summary> 定义一组方法，它支持自定义Sql语句的格式。    /// </summary>    public interface ISaw    {        /// <summary> 解释二元操作        /// </summary>        /// <param name="left">左元素</param>        /// <param name="Operator">二元操作符</param>        /// <param name="right">右元素</param>        string BinaryOperation(string left, BinaryOperator @operator, string right);        /// <summary> 解释Contains操作        /// </summary>        /// <param name="not">是否为not</param>        /// <param name="item">要在集合中查找的对象</param>        /// <param name="array">要查找的集合</param>        string ContainsOperation(bool not, string item, string[] array);        /// <summary> 向参数集合中追加一个任意类型的参数,并返回参数名sql表达式        /// </summary>        /// <param name="obj">需要追加的参数值</param>        /// <param name="parameters">参数集合</param>        string AddObject(object obj, ICollection<DbParameter> parameters);        /// <summary> 向参数集合中追加一个数字类型的参数,并返回参数名sql表达式        /// </summary>        /// <param name="number">需要追加的数字</param>        /// <param name="parameters">参数集合</param>        string AddNumber(IConvertible number, ICollection<DbParameter> parameters);        /// <summary> 向参数集合中追加一个布尔类型的参数,并返回参数名sql表达式        /// </summary>        /// <param name="obj">需要追加的布尔值</param>        /// <param name="parameters">参数集合</param>        string AddBoolean(bool value, ICollection<DbParameter> parameters);        /// <summary> 向参数集合中追加当前时间,并返回参数名sql表达式        /// </summary>        /// <param name="parameters">参数集合</param>        string AddTimeNow(ICollection<DbParameter> parameters);        /// <summary> 获取实体类型所映射的表名        /// </summary>        /// <param name="type">实体类型</param>        /// <param name="alias">别名</param>        string GetTable(Type type, string alias);        /// <summary> 获取实体属性或字段所映射的列名        /// </summary>        /// <param name="table">表名或表别名</param>        /// <param name="type">实体属性或字段</param>        string GetColumn(string table, MemberInfo member);        /// <summary> 获取列名和列别名组合后的sql表达式        /// </summary>        /// <param name="columnName">列名</param>        /// <param name="alias">列别名</param>        string GetColumn(string columnName, string alias);        /// <summary> 将.NET中的方法解释为sql表达式        /// </summary>        /// <param name="method">需解释的方法</param>        /// <param name="target">方法调用者</param>        /// <param name="args">方法参数</param>        /// <returns></returns>        string ParseMethod(MethodInfo method, SawDust target, SawDust[] args);    }

ISaw

    /// <summary> 表达式树解析结果    /// </summary>    public struct SawDust    {        /// <summary> 结果类型        /// </summary>        public readonly DustType Type;        /// <summary> 结果值        /// </summary>        public readonly Object Value;        /// <summary> 无论结果类型 强制转换为Sql语句,DustType.Undefined抛出异常        /// </summary>        public string ToSql();                /// <summary>  是否是非DustType.Sql和DustType.Undefined类型        /// </summary>        public bool IsObject { get;}    }

SawDust(不包含实现)

    /// <summary> 表达式解析结果类型    /// </summary>    [System.Serializable]    public enum DustType    {        /// <summary> 未知        /// </summary>        Undefined = 0,        /// <summary> sql语句        /// </summary>        Sql = 1,        /// <summary> 未知类型        /// </summary>        Object = 2,        /// <summary> 数字        /// </summary>        Number = 3,        /// <summary> 数组        /// </summary>        Array = 4,        /// <summary> 布尔值        /// </summary>        Boolean = 5,        /// <summary> 时间        /// </summary>        DateTime = 6,        /// <summary> 二进制        /// </summary>        Binary = 7,        /// <summary> 字符串        /// </summary>        String = 8,    }

DustType

/// <summary> Sql表达式    /// </summary>    public struct SqlExpr    {        public static explicit operator SqlExpr(string value);        public static implicit operator bool(SqlExpr value);        public static implicit operator byte(SqlExpr value);        public static implicit operator char(SqlExpr value);        public static implicit operator DateTime(SqlExpr value);        public static implicit operator decimal(SqlExpr value);        public static implicit operator double(SqlExpr value);        public static implicit operator short(SqlExpr value);        public static implicit operator int(SqlExpr value);        public static implicit operator long(SqlExpr value);        public static implicit operator sbyte(SqlExpr value);        public static implicit operator float(SqlExpr value);        public static implicit operator string(SqlExpr value);        public static implicit operator ushort(SqlExpr value);        public static implicit operator uint(SqlExpr value);        public static implicit operator ulong(SqlExpr value);        public static implicit operator Guid(SqlExpr value);        public static implicit operator Byte[](SqlExpr value);    }

SqlExpr

    /// <summary> 支持自定义Sql语句格式基类。    /// </summary>    public abstract class BaseSaw : ISaw    {        /// <summary> 初始化并提供 DbProviderFactory        /// </summary>        /// <param name="factory"></param>        protected BaseSaw(DbProviderFactory factory);        /*         * 接口已定义方法略...         */        /// <summary> 解释未知的方法        /// </summary>        /// <param name="method">需解释的方法</param>        /// <param name="target">方法调用者</param>        /// <param name="args">方法参数</param>        protected virtual string ParseUnknownMethod(MethodInfo method, SawDust target, SawDust[] args);        /// <summary> 获取新的数据库参数        /// </summary>        /// <param name="obj">参数值</param>        protected virtual DbParameter GetDbParameter(object obj);        /// <summary> 别名分隔符 默认 AS ,如 Table AS it        /// </summary>        protected virtual string AliasSeparator { get; }        /// <summary> 解释按位运算 与,或,非        /// </summary>        /// <param name="val1">操作数1</param>        /// <param name="val2">操作数2</param>        /// <param name="opt">按位操作符</param>        protected virtual string BitOperation(string val1, string val2, BitOperator opt);        /// <summary> 解释取余运算        /// </summary>        /// <param name="val1">操作数1</param>        /// <param name="val2">操作数2</param>        /// <returns></returns>        protected virtual string ModuloOperation(string val1, string val2);        /// <summary> 解释幂运算        /// </summary>        /// <param name="val1">操作数1</param>        /// <param name="val2">操作数2</param>        /// <returns></returns>        protected virtual string PowerOperation(string val1, string val2);        /// <summary> 解释位移运算        /// </summary>        /// <param name="val1">操作数1</param>        /// <param name="val2">操作数2</param>        /// <param name="opt">按位操作符</param>        protected virtual string ShiftOperation(string val1, string val2, ShiftOperator opt);        /// <summary> 解释 String.Trim 方法        /// </summary>        /// <param name="target">方法调用者</param>        /// <param name="arg">方法参数</param>        protected virtual string StringTrim(string target, string arg);        /// <summary> 解释 String.TrimEnd 方法        /// </summary>        /// <param name="target">方法调用者</param>        /// <param name="arg">方法参数</param>        protected virtual string StringTrimEnd(string target, string arg);        /// <summary> 解释 String.TrimStart 方法        /// </summary>        /// <param name="target">方法调用者</param>        /// <param name="arg">方法参数</param>        protected virtual string StringTrimStart(string target, string arg);        /// <summary> 解释 String.IsNullOrEmpty 方法        /// </summary>        /// <param name="target">方法调用者</param>        protected virtual string StringIsNullOrEmpty(string target);        /// <summary> 解释 String.IsNullOrWhiteSpace 方法        /// </summary>        /// <param name="target">方法调用者</param>        protected virtual string StringIsNullOrWhiteSpace(string target);        /// <summary> 解释 String.Length 方法        /// </summary>        /// <param name="target">方法调用者</param>        protected virtual string StringLength(string target);        /// <summary> 解释 Object.ToString 方法        /// </summary>        /// <param name="type">调用者类型</param>        /// <param name="target">方法调用者</param>        /// <param name="format">格式化参数</param>        protected virtual string ObjectToString(DustType type, string target, string format);        /// <summary> 解释 DateTime 中的数据        /// </summary>        /// <param name="datetime">方法调用者</param>        protected virtual string DateTimeToField(string datetime, DateTimeField field);        /// <summary> 解释各种 Number.Parse 方法        /// </summary>        /// <param name="target">string对象</param>        protected virtual string SrtingToNumber(string target);        #region abstract        /// <summary> 返回实体类型所映射的表名        /// </summary>        /// <param name="type">实体类型</param>        protected abstract string TableName(Type type);        /// <summary> 返回实体属性或字段所映射的列名        /// </summary>        /// <param name="member">实体属性或字段</param>        protected abstract string ColumnName(MemberInfo member);        /// <summary> 参数的前缀符号,如SqlServer中的@,Oracle中的:        /// </summary>        protected abstract string ParameterPreFix { get; }        /// <summary> 在数据库中表示当前时间的表达式,如SqlServer中的getdate,Oracle中的SYSDATE        /// </summary>        protected abstract string TimeNow { get; }        /// <summary> 解释Like操作        /// </summary>        /// <param name="val1">操作数1</param>        /// <param name="val2">操作数2</param>        /// <param name="opt">按位操作符</param>        protected abstract string LikeOperation(string val1, string val2, LikeOperator opt);        #endregion    }

BaseSaw(不包含实现)

    /// <summary> 二元操作符枚举    /// </summary>    [Serializable]    public enum BinaryOperator    {        /// <summary> 加        /// </summary>        Add,        /// <summary> 减        /// </summary>        Subtract,        /// <summary> 除        /// </summary>        Divide,        /// <summary> 取余        /// </summary>        Modulo,        /// <summary> 乘        /// </summary>        Multiply,        /// <summary> 幂运算        /// </summary>        Power,        /// <summary> 位移运算 a &lt;&lt; b        /// </summary>        LeftShift,        /// <summary> 位移运算 a &gt;&gt; b        /// </summary>        RightShift,        /// <summary> 与 a &amp;&amp; b 或 a AND b        /// </summary>        And,        /// <summary> 或 a || b 或 a OR b        /// </summary>        Or,        /// <summary> 等于 a == b        /// </summary>        Equal,        /// <summary> 不等于 a != b 或 a <> b        /// </summary>        NotEqual,        /// <summary> 大于 a &gt; b        /// </summary>        GreaterThan,        /// <summary> 大于等于 a &gt;= b        /// </summary>        GreaterThanOrEqual,        /// <summary> 小于 a &lt; b        /// </summary>        LessThan,        /// <summary> 小于等于 a &lt;= b        /// </summary>        LessThanOrEqual,        /// <summary> LIKE操作 a LIKE %b%        /// </summary>            Contains,                 /// <summary> LIKE操作 a LIKE b%        /// </summary>            StartWith,                /// <summary> LIKE操作 a LIKE %b        /// </summary>            EndWith,                  /// <summary> LIKE操作 a NOT LIKE %b%        /// </summary>            NotContains,              /// <summary> LIKE操作 a NOT LIKE b%        /// </summary>            NotStartWith,             /// <summary> LIKE操作 a NOT LIKE %b        /// </summary>        NotEndWith,        /// <summary> 位运算 如 a &amp; b        /// </summary>        BitAnd,        /// <summary> 位运算 如 a | b        /// </summary>        BitOr,        /// <summary> 位运算 如 a ^ b        /// </summary>        BitXor,    }    /// <summary> 按位操作符枚举    /// </summary>    [Serializable]    public enum BitOperator    {        /// <summary> 位运算 如 a &amp; b        /// </summary>        And,        /// <summary> 位运算 如 a | b        /// </summary>        Or,        /// <summary> 位运算 如 a ^ b        /// </summary>        Xor,    }    /// <summary> Like操作符枚举    /// </summary>    [Serializable]    public enum LikeOperator    {        /// <summary> LIKE操作 a LIKE %b%        /// </summary>            Contains,        /// <summary> LIKE操作 a LIKE b%        /// </summary>            StartWith,        /// <summary> LIKE操作 a LIKE %b        /// </summary>            EndWith,        /// <summary> LIKE操作 a NOT LIKE %b%        /// </summary>            NotContains,        /// <summary> LIKE操作 a NOT LIKE b%        /// </summary>            NotStartWith,        /// <summary> LIKE操作 a NOT LIKE %b        /// </summary>        NotEndWith,    }    /// <summary> 位移操作符枚举    /// </summary>    [Serializable]    public enum ShiftOperator    {                 /// <summary> 位移运算 a &lt;&lt; b        /// </summary>        Left,        /// <summary> 位移运算 a &gt;&gt; b        /// </summary>        Right,    }    /// <summary> 时间字段    /// </summary>    [Serializable]    public enum DateTimeField    {        /// <summary> 年        /// </summary>        Year,        /// <summary> 月        /// </summary>        Month,        /// <summary> 日        /// </summary>        Day,        /// <summary> 时        /// </summary>        Hour,        /// <summary> 分        /// </summary>        Minute,        /// <summary> 秒        /// </summary>        Second,        /// <summary> 星期        /// </summary>        Week,    }

其他枚举

再来一个已实现的MsSqlSaw

    public class MsSqlSaw : BaseSaw    {        public static MsSqlSaw Instance = new MsSqlSaw();        private MsSqlSaw() : base(System.Data.SqlClient.SqlClientFactory.Instance) { }        private static HashSet<string> KeyWords = InitKeyWords();        private static HashSet<string> InitKeyWords()        {            return new HashSet<string>("ABSOLUTE,ACTION,ADA,ADD,ADMIN,AFTER,AGGREGATE,ALIAS,ALL,ALLOCATE,ALTER,AND,ANY,ARE,ARRAY,AS,ASC,ASSERTION,AT,AUTHORIZATION,AVG,BACKUP,BEFORE,BEGIN,BETWEEN,BINARY,BIT,BIT_LENGTH,BLOB,BOOLEAN,BOTH,BREADTH,BREAK,BROWSE,BULK,BY,CALL,CASCADE,CASCADED,CASE,CAST,CATALOG,CHAR,CHARACTER,CHARACTER_LENGTH,CHAR_LENGTH,CHECK,CHECKPOINT,CLASS,CLOB,CLOSE,CLUSTERED,COALESCE,COLLATE,COLLATION,COLUMN,COMMIT,COMPLETION,COMPUTE,CONNECT,CONNECTION,CONSTRAINT,CONSTRAINTS,CONSTRUCTOR,CONTAINS,CONTAINSTABLE,CONTINUE,CONVERT,CORRESPONDING,COUNT,CREATE,CROSS,CUBE,CURRENT,CURRENT_DATE,CURRENT_PATH,CURRENT_ROLE,CURRENT_TIME,CURRENT_TIMESTAMP,CURRENT_USER,CURSOR,CYCLE,DATA,DATABASE,DATE,DAY,DBCC,DEALLOCATE,DEC,DECIMAL,DECLARE,DEFAULT,DEFERRABLE,DEFERRED,DELETE,DENY,DEPTH,DEREF,DESC,DESCRIBE,DESCRIPTOR,DESTROY,DESTRUCTOR,DETERMINISTIC,DIAGNOSTICS,DICTIONARY,DISCONNECT,DISK,DISTINCT,DISTRIBUTED,DOMAIN,DOUBLE,DROP,DUMMY,DUMP,DYNAMIC,EACH,ELSE,END,END-EXEC,EQUALS,ERRLVL,ESCAPE,EVERY,EXCEPT,EXCEPTION,EXEC,EXECUTE,EXISTS,EXIT,EXTERNAL,EXTRACT,FALSE,FETCH,FILE,FILLFACTOR,FIRST,FLASE,FLOAT,FOR,FOREIGN,FORTRAN,FOUND,FREE,FREETEXT,FREETEXTTABLE,FROM,FULL,FUNCTION,GENERAL,GET,GLOBAL,GO,GOTO,GRANT,GROUP,GROUPING,HAVING,HOLDLOCK,HOST,HOUR,IDENTITY,IDENTITYCOL,IDENTITY_INSERT,IF,IGNORE,IMMEDIATE,IN,INCLUDE,INDEX,INDICATOR,INITIALIZE,INITIALLY,INNER,INOUT,INPUT,INSENSITIVE,INSERT,INT,INTEGER,INTERSECT,INTERVAL,INTO,IS,ISOLATION,ITERATE,JOIN,KEY,KILL,LANGUAGE,LARGE,LAST,LATERAL,LEADING,LEFT,LESS,LEVEL,LIKE,LIMIT,LINENO,LOAD,LOCAL,LOCALTIME,LOCALTIMESTAMP,LOCATOR,LOWER,MAP,MATCH,MAX,MIN,MINUTE,MODIFIES,MODIFY,MODULE,MONTH,NAMES,NATIONAL,NATURAL,NCHAR,NCLOB,NEW,NEXT,NO,NOCHECK,NONCLUSTERED,NONE,NOT,NULL,NULLIF,NUMERIC,OBJECT,OCTET_LENGTH,OF,OFF,OFFSETS,OLD,ON,ONLY,OPEN,OPENDATASOURCE,OPENQUERY,OPENROWSET,OPENxml,OPERATION,OPTION,OR,ORDER,ORDINALITY,OUT,OUTER,OUTPUT,OVER,OVERLAPS,PAD,PARAMETER,PARAMETERS,PARTIAL,PASCAL,PATH,PERCENT,PLAN,POSITION,POSTFIX,PRECISION,PREFIX,PREORDER,PREPARE,PRESERVE,PRIMARY,PRINT,PRIOR,PRIVILEGES,PROC,PROCEDURE,PUBLIC,RAISERROR,READ,READS,READTEXT,REAL,RECONFIGURE,RECURSIVE,REF,REFERENCES,REFERENCING,RELATIVE,REPLICATION,RESTORE,RESTRICT,RESULT,RETURN,RETURNS,REVOKE,RIGHT,ROLE,ROLLBACK,ROLLUP,ROUTINE,ROW,ROWCOUNT,ROWGUIDCOL,ROWS,RULE,SAVE,SAVEPOINT,SCHEMA,SCOPE,SCROLL,SEARCH,SECOND,SECTION,SELECT,SEQUENCE,session,SESSION_USER,SET,SETS,SETUSER,SHUTDOWN,SIZE,SMALLINT,SOME,SPACE,SPECIFIC,SPECIFICTYPE,SQL,SQLCA,SQLCODE,SQLERROR,SQLEXCEPTION,SQLSTATE,SQLWARNING,START,STATE,STATEMENT,STATIC,STATISTICS,STRUCTURE,SUBSTRING,SUM,SYSTEM_USER,TABLE,TEMPORARY,TERMINATE,TEXTSIZE,THAN,THEN,TIME,TIMESTAMP,TIMEZONE_HOUR,TIMEZONE_MINUTE,TO,TOP,TRAILING,TRAN,TRANSACTION,TRANSLATE,TRANSLATION,TREAT,TRIGGER,TRIM,TRUE,TRUNCATE,TSEQUAL,UNDER,UNION,UNIQUE,UNKNOWN,UNNEST,UPDATE,UPDATETEXT,UPPER,USAGE,USE,USER,USING,VALUE,VALUES,VARCHAR,VARIABLE,VARYING,VIEW,WAITFOR,WHEN,WHENEVER,WHERE,WHILE,WITH,WITHOUT,WORK,WRITE,WRITETEXT,YEAR,ZONE".Split(','), StringComparer.OrdinalIgnoreCase);        }        protected override string TableName(Type type)        {            var name = type.Name;            if (KeyWords.Contains(name))            {                return string.Concat("[", name, "]");            }            return name;        }        protected override string ColumnName(MemberInfo member)        {            var name = member.Name;            if (KeyWords.Contains(name))            {                return string.Concat("[", name, "]");            }            return name;        }        protected override string ParameterPreFix { get { return "@"; } }        protected override string TimeNow { get { return "GETDATE()"; } }        protected override string LikeOperation(string val1, string val2, LikeOperator opt)        {            switch (opt)            {                case LikeOperator.Contains:                    return string.Concat(val1, " LIKE '%' + ", val2, " + '%'");                case LikeOperator.StartWith:                    return string.Concat(val1, " LIKE ", val2, " + '%'");                case LikeOperator.EndWith:                    return string.Concat(val1, " LIKE '%' + ", val2);                case LikeOperator.NotContains:                    return string.Concat(val1, " NOT LIKE '%' + ", val2, " + '%'");                case LikeOperator.NotStartWith:                    return string.Concat(val1, " NOT LIKE ", val2, " + '%'");                case LikeOperator.NotEndWith:                    return string.Concat(val1, " NOT LIKE '%' + ", val2);                default:                    throw new ArgumentOutOfRangeException("opt");            }        }        protected override string BitOperation(string val1, string val2, BitOperator opt)        {            switch (opt)            {                case BitOperator.And:                    return string.Concat(val1, " & ", val2);                case BitOperator.Or:                    return string.Concat(val1, " | ", val2);                case BitOperator.Xor:                    return string.Concat(val1, " ^ ", val2);                default:                    throw new ArgumentOutOfRangeException("opt");            }        }        protected override string StringTrim(string target, string arg)        {            if (arg != null)            {                throw new NotSupportedException("不支持参数");            }            return string.Concat("LTRIM(RTRIM(", target, "))");        }        protected override string StringTrimEnd(string target, string arg)        {            if (arg != null)            {                throw new NotSupportedException("不支持参数");            }            return string.Concat("RTRIM(", target, ")");        }        protected override string StringTrimStart(string target, string arg)        {            if (arg != null)            {                throw new NotSupportedException("不支持参数");            }            return string.Concat("LTRIM(", target, ")");        }        protected override string StringLength(string target)        {            return string.Concat("LEN(", target, ")");        }        protected override string SrtingToNumber(string target)        {            return string.Concat("CAST(", target, " as decimal)");        }        protected override string ObjectToString(DustType type, string target, string format)        {            switch (type)            {                case DustType.Undefined:                    break;                case DustType.Sql:                    break;                case DustType.Object:                    break;                case DustType.Number:                    if (format != null)                    {                        throw new NotSupportedException("不支持参数");                    }                    return string.Concat("CAST(", target, " as NVARCHAR)");                case DustType.Array:                    break;                case DustType.Boolean:                    break;                case DustType.DateTime:                    switch (format)                    {                        case "'HH:mm'":                            return string.Concat("CONVERT(VARCHAR(5),", target, ",114)");                        case "'HH:mm:ss'":                            return string.Concat("CONVERT(VARCHAR(8),", target, ",114)");                        case "'HH:mm:ss.fff'":                            return string.Concat("CONVERT(VARCHAR(12),", target, ",114)");                        case "'yyyy-MM-dd'":                            return string.Concat("CONVERT(VARCHAR(10),", target, ",21)");                        case "'yyyy-MM-dd HH:mm'":                            return string.Concat("CONVERT(VARCHAR(16),", target, ",21)");                        case "'yyyy-MM-dd HH:mm:ss'":                            return string.Concat("CONVERT(VARCHAR(19),", target, ",21)");                        case "'yyyy-MM-dd HH:mm:ss.fff'":                            return string.Concat("CONVERT(VARCHAR(23),", target, ",21)");                        case "'yy/MM/dd'":                            return string.Concat("CONVERT(VARCHAR(8),", target, ",111)");                        case "'yyMMdd'":                            return string.Concat("CONVERT(VARCHAR(6),", target, ",112)");                        default:                            break;                    }                    throw new NotSupportedException("不支持当前参数");                case DustType.Binary:                    break;                case DustType.String:                    break;                default:                    break;            }            return base.ObjectToString(type, target, format);        }        protected override string DateTimeToField(string datetime, DateTimeField field)        {            switch (field)            {                case DateTimeField.Year:                    return string.Concat("DATEPART(YYYY, ", datetime, ")");                case DateTimeField.Month:                    return string.Concat("DATEPART(mm, ", datetime, ")");                case DateTimeField.Day:                    return string.Concat("DATEPART(dd, ", datetime, ")");                case DateTimeField.Hour:                    return string.Concat("DATEPART(hh, ", datetime, ")");                case DateTimeField.Minute:                    return string.Concat("DATEPART(mi, ", datetime, ")");                case DateTimeField.Second:                    return string.Concat("DATEPART(ss, ", datetime, ")");                case DateTimeField.Week:                    return string.Concat("(DATEPART(w, ", datetime, ") - 1)");                default:                    throw new ArgumentOutOfRangeException("field");            }        }    }