有话说

之前我写了3篇关于表达式树解析的文章

 

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

1. 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
2. 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 == ''

    

3. 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

4. 对 DateTime.Now 的处理 : 
   如 :  Where(u => u.Birthday < DateTime.Now) //可以被解析为 BIRTHDAY < SYSDATE 或 BIRTHDAY < GETDATE() 
5. 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 
6. 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
     
      
       > 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
      
        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
       
         ToColumnsAndValues(ISaw saw);    // 转换Sql语句过程中产生的参数    ICollection
        
          Parameters { get; }}
        
       
      

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

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

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

/// 
 Sql表达式    /// 
    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);    }

 

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

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

 

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
      
        KeyWords = InitKeyWords();        private static HashSet
       
         InitKeyWords()        {            return new HashSet
        
         ("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");            }        }    }
        
       
      

 

部分解释结果展示(以OracleSaw为例)

下载地址

广告

对C#感兴趣的朋友可以来群里讨论,入群方式见签名