ORM之二：核心接口与扩展操作

一、数据库提供者接口

　　 /// <summary>
    /// 数据库提供者
    /// </summary>
    public interface IDbProvider : IDisposable
    {
        /// <summary>
        /// 初始化数据库连接信息
        /// </summary>
        /// <param name="dbConnInfo"></param>
        /// <returns></returns>
        IDbProvider Init(DbConnInfo dbConnInfo);

        /// <summary>
        /// 获取Lambda语法的数据操作对象
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        IReqository<T> GetReqository<T>() where T : class, new();

        ///<summary>
        /// 获取Linq语法的数据查询对象
        ///</summary>
        ///<typeparam name="T"></typeparam>
        ///<returns></returns>
        IQuery<T> GetQuery<T>() where T : class, new();

        ///<summary>
        /// 扩展操作
        ///</summary>
        ///<returns></returns>
        IDbExtension GetDbExtension();

        /// <summary>
        /// 事务开启
        /// </summary>
        void Begin();

        /// <summary>
        /// 事务提交
        /// </summary>
        void Commit();

        /// <summary>
        /// 事务回滚
        /// </summary>
        void Rollback();

    }

    ///<summary>
    /// 扩展数据库提供者
    ///</summary>
    internal interface IDbProviderExtend : IDbProvider
    {
        IDbExecutor DbExecutor { get; }
    }

二、单表操作

    /// <summary>
    /// 标准的数据层接口
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public interface IReqository<T> where T : class
    {
        /// <summary>
        /// 新增实体对象
        /// </summary>
        /// <param name="entity">实体对象</param>
        void Insert(T entity);

        /// <summary>
        /// 批量新增实体对象
        /// </summary>
        /// <param name="entitys"></param>
        void Insert(IList<T> entitys);

        /// <summary>
        /// 根据条件表达式自动删除对应数据
        /// </summary>
        /// <param name="where"></param>
        /// <returns></returns>
        int Delete(Expression<Func<T, bool>> where);

        /// <summary>
        /// 根据条件表达式将映射对象的数据进行局部更新
        /// </summary>
        /// <typeparam name="TResult"></typeparam>
        /// <param name="update"></param>
        /// <param name="where"></param>
        /// <returns></returns>
        int Update<TResult>(Expression<Func<T, TResult>> update, Expression<Func<T, bool>> where) where TResult : class;

        /// <summary>
        /// 根据条件表达式获得[Top 1]实体对象
        /// </summary>
        /// <param name="where"></param>
        /// <param name="nolock">是否允许脏读</param>
        /// <returns></returns>
        T Single(Expression<Func<T, bool>> where, bool nolock = false);

        /// <summary>
        /// 根据条件表达式获得实体对象列表
        /// </summary>
        /// <param name="where">条件表达式</param>
        /// <param name="nolock">是否允许脏读</param>
        /// <returns></returns>
        IList<T> Select(Expression<Func<T, bool>> where, bool nolock = false);

        /// <summary>
        /// 根据条件表达式获得指定记录的条数
        /// </summary>
        /// <param name="where"></param>
        /// <param name="nolock">是否允许脏读</param>
        /// <returns></returns>
        int Count(Expression<Func<T, bool>> where, bool nolock = false);

        /// <summary>
        /// 根据条件表达式获取某列的和
        /// </summary>
        /// <param name="select"></param>
        /// <param name="where"></param>
        /// <param name="noLock"></param>
        /// <returns></returns>
        object Sum<TResult>(Expression<Func<T, TResult>> select, Expression<Func<T, bool>> where, bool noLock = false);

    }

三、多表操作

    ///<summary>
    /// 多表查询对象接口
    ///</summary>
    ///<typeparam name="T">数据实体</typeparam>
    public interface IQuery<out T> : IOrderedQueryable<T>
    {
    }

    ///<summary>
    /// IQuery的扩展方法
    ///</summary>
    public static class Query
    {
        ///<summary>
        /// 分页功能
        ///</summary>
        ///<param name="source"></param>
        ///<param name="rowCount">每页的行数</param>
        ///<param name="pageNumber">第几页</param>
        ///<typeparam name="TSource"></typeparam>
        ///<returns></returns>
        public static IQueryable<TSource> Page<TSource>(this IQueryable<TSource> source, int rowCount, int pageNumber)
        {
            if (source == null)
            {
                throw new ArgumentNullException("source");
            }
            return source.Provider.CreateQuery<TSource>(Expression.Call(null,
                ((MethodInfo) MethodBase.GetCurrentMethod()).MakeGenericMethod(new Type[]
                {
                    typeof (TSource)
                }),
                new Expression[]
                {
                    source.Expression,
                    Expression.Constant(rowCount),
                    Expression.Constant(pageNumber)
                }));
        }

        ///<summary>
        /// 扩展join功能
        ///</summary>
        ///<param name="source"></param>
        ///<param name="joins"></param>
        ///<typeparam name="TSource"></typeparam>
        ///<returns></returns>
        public static IQueryable<TSource> SetJoinMode<TSource>(this IQueryable<TSource> source, params JoinMode[] joins)
        {
            if (source == null)
            {
                throw new ArgumentNullException("source");
            }

            return source.Provider.CreateQuery<TSource>(Expression.Call(null,
                    ((MethodInfo) MethodBase.GetCurrentMethod()).
                        MakeGenericMethod(new Type[] {typeof (TSource)}),
                    new Expression[]
                    {
                        source.Expression,
                        Expression.Constant(joins)
                    }));
        }
    }

    ///<summary>
    ///</summary>
    public enum JoinMode
    {
        ///<summary>
        /// 内连接
        ///</summary>
        Inner,

        ///<summary>
        /// 左连接
        ///</summary>
        Left,

        ///<summary>
        /// 右连接
        ///</summary>
        Right,

        ///<summary>
        /// 全连接
        ///</summary>
        Full
    }

四、扩展操作

/// <summary>
    /// 扩展操作
    /// </summary>
    public interface IDbExtension
    {
        /// <summary>
        /// 执行存储过程返回影响行数
        /// </summary>
        /// <param name="name"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        int ExcuteProcNonQuery(string name, DbParameterCollection parameters = null);

        /// <summary>
        /// 执行存储过程返回DataSet
        /// </summary>
        /// <param name="name"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        DataSet ExcuteProcQuery(string name, DbParameterCollection parameters = null);

        /// <summary>
        /// 执行存储过程返回泛型集合
        /// </summary>
        /// <typeparam name="TResult"></typeparam>
        /// <param name="name"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        IList<TResult> ExcuteProcReader<TResult>(string name, DbParameterCollection parameters = null);

        /// <summary>
        /// 执行sql语句返回影响行数
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        int ExcuteNonQuery(string sql, DbParameterCollection parameters = null);

        /// <summary>
        /// 执行sql语句返回DataSet
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        DataSet ExcuteQuery(string sql, DbParameterCollection parameters = null);

        /// <summary>
        /// 执行sql语句返回泛型集合
        /// </summary>
        /// <typeparam name="TResult"></typeparam>
        /// <param name="sql"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        IList<TResult> ExcuteQuery<TResult>(string sql, DbParameterCollection parameters = null);
    }