小白开学Asp.Net Core《二》

小白开学Asp.Net Core《二》

　　——数据仓储层（Repositroy）

一、历史现象

　　在后端开发中，数据库操作是最频繁的，每一个开发人员都会接触，甚至不少开发人员每天的工作就是与数据库打交道。所以可见数据库操作是多长重要。

　　在现在的开发过程中，大多数开发人员只是以编写SQL语句的方式操作数据库，这种方式是操作数据库最原始的方式，简单高效，但是在编写SQL语句的过程中，极容易因粗心大意写出BUG，这样就会出现一种现象，开发人员面对一堆SQL语句的DEBUG，而且每次都需要开发人员自己去手写SQL语句，其开发效率极低。不同的数据库所需的SQL语句也还是有差异的，这就需要开发人员学习不同的数据库SQL语法。而且在项目开发中难免会遇到更换数据库的情况，这时还需要花费大量的精力去修改SQL语句。

二、数据仓储层

　　由于以上缺点，所以仓储层因此而生。

　　数据仓储层主要是对数据库操作CRUD的封装。使开发人员进行CRUD只需要极为简单的代码即可完成。本层还提供了数据库事务的支持，为数据库操作提供必备的保障。使用本层提供的接口，无需关心具体的业务逻辑实现，哪怕更换数据库，也无需更改业务逻辑代码，只需要更改简单的数据库配置即可。总之，本层为开发人员对数据库的操作提供了简单高效的操作接口。

三、继承关系图

　　  （继承图） 

　　 （接口定义）

 四、代码实现

#region Async
/// <summary>
/// 查询所有数据(无分页,请慎用)
/// </summary>
/// <returns></returns>
Task<IEnumerable<T>> FindAllAsync();

/// <summary>
/// 根据条件查询数据
/// </summary>
/// <param name="predicate">条件表达式树</param>
/// <param name="orderBy">排序</param>
/// <returns>泛型实体集合</returns>
Task<IEnumerable<T>> FindListByClauseAsync(Expression<Func<T, bool>> predicate, string orderBy = "");

Task<IEnumerable<T>> PageQueryAsync(Expression<Func<T, bool>> predicate, int skip = 0, int pageSize = 15, string orderBy = "");
Task<T> FindByClauseAsync(Expression<Func<T, bool>> predicate);
/// <summary>
/// 插入实体数据
/// </summary>
/// <param name="entity"></param>
/// <returns></returns>
Task<int> InsertAsync(T entity);
/// <summary>
/// 更新实体数据
/// </summary>
/// <param name="entity"></param>
/// <returns></returns>
Task<bool> UpdateAsync(T entity);
/// <summary>
/// DeleteAsync
/// </summary>
/// <param name="entity"></param>
/// <returns></returns>
Task<bool> DeleteAsync(T entity);
/// <summary>
/// DeleteAsync
/// </summary>
/// <param name="where">条件表达式</param>
/// <returns></returns>
Task<bool> DeleteAsync(Expression<Func<T, bool>> @where);
/// <summary>
/// DeleteByIdAsync
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
Task<bool> DeleteByIdAsync(object id);
/// <summary>
/// DeleteByIdsAsync
/// </summary>
/// <param name="ids">ids</param>
/// <returns></returns>
Task<bool> DeleteByIdsAsync(object[] ids);
/// <summary>
/// InsertAsync
/// </summary>
/// <param name="t"></param>
/// <returns></returns>
Task<DbResult<Task<int>>> InsertAsync(List<T> t);
/// <summary>
/// DeleteByClauseAsync
/// </summary>
/// <param name="predicate"></param>
/// <returns></returns>
Task<int> DeleteByClauseAsync(Expression<Func<T, bool>> predicate);

/// <summary>
/// 事务
/// </summary>
/// <param name="func"></param>
/// <returns></returns>
Task<DbResult<T>> UserTranAsync(Func<T> func);

/// <summary>
/// 事务
/// </summary>
/// <param name="action"></param>
Task<DbResult<bool>> UserTranAsync(Action action);
#endregion

五、实现　

/// <summary>
/// GenericRepositoryBase
/// </summary>
/// <typeparam name="T"></typeparam>
public class GenericSqlSugarRepositoryBase<T> : ISqlSugarRepository<T> where T : class, new()
{
#region Sync
/// <summary>
/// 根据主键查询
/// </summary>
/// <param name="pkValue">主键</param>
/// <returns></returns>
public T FindById(object pkValue)
{
using (var db = DbFactory.DB)
{
return db.Queryable<T>().InSingle(pkValue);
}
}

/// <summary>
/// 查询所有数据(无分页,请慎用)
/// </summary>
/// <returns></returns>
public IEnumerable<T> FindAll()
{
using (var db = DbFactory.DB)
{
return db.Queryable<T>().ToList();
}
}

/// <summary>
/// 根据条件查询数据
/// </summary>
/// <param name="predicate">条件表达式树</param>
/// <param name="orderBy">排序</param>
/// <returns>泛型实体集合</returns>
public IEnumerable<T> FindListByClause(Expression<Func<T, bool>> predicate, string orderBy = "")
{
using (var db = DbFactory.DB)
{
var query = db.Queryable<T>().Where(predicate);
if (!string.IsNullOrEmpty(orderBy))
query.OrderBy(orderBy);
return query.ToList();
}
}

/// <summary>
/// 根据条件分页查询
/// </summary>
/// <param name="predicate">条件表达式树</param>
/// <param name="skip"></param>
/// <param name="pageSize"></param>
/// <param name="orderBy"></param>
/// <returns></returns>
public IEnumerable<T> PageQuery(Expression<Func<T, bool>> predicate, int skip, int pageSize = 15,
string orderBy = "")
{
using (var db = DbFactory.DB)
{
if (skip > 0)
skip = pageSize * skip;
var query = db.Queryable<T>().Where(predicate).Skip(skip).Take(pageSize);
if (!string.IsNullOrEmpty(orderBy))
query = query.OrderBy(orderBy);
return query.ToList();
}
}

/// <summary>
/// 根据条件查询数据
/// </summary>
/// <param name="predicate">条件表达式树</param>
/// <returns></returns>
public T FindByClause(Expression<Func<T, bool>> predicate)
{
using (var db = DbFactory.DB)
{
return db.Queryable<T>().First(predicate);
}
}

/// <summary>
/// 写入实体数据
/// </summary>
/// <param name="entity">实体类</param>
/// <returns></returns>
public int Insert(T entity)
{
using (var db = DbFactory.DB)
{
return db.Insertable(entity).ExecuteCommand();
}
}

/// <summary>
/// 更新实体数据
/// </summary>
/// <param name="entity"></param>
/// <returns></returns>
public bool Update(T entity)
{
using (var db = DbFactory.DB)
{
return db.Updateable(entity).ExecuteCommand() > 0;
}
}

/// <summary>
/// 删除数据
/// </summary>
/// <param name="entity">实体类</param>
/// <returns></returns>
public bool Delete(T entity)
{
using (var db = DbFactory.DB)
{
return db.Deleteable(entity).ExecuteCommand() > 0;
}
}

/// <summary>
/// 删除数据
/// </summary>
/// <param name="where">过滤条件</param>
/// <returns></returns>
public bool Delete(Expression<Func<T, bool>> @where)
{
using (var db = DbFactory.DB)
{
return db.Deleteable<T>(@where).ExecuteCommand() > 0;
}
}

/// <summary>
/// 删除指定ID的数据
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
public bool DeleteById(object id)
{
using (var db = DbFactory.DB)
{
return db.Deleteable<T>(id).ExecuteCommand() > 0;
}
}

/// <summary>
/// 删除指定ID集合的数据(批量删除)
/// </summary>
/// <param name="ids"></param>
/// <returns></returns>
public bool DeleteByIds(object[] ids)
{
using (var db = DbFactory.DB)
{
return db.Deleteable<T>().In(ids).ExecuteCommand() > 0;
}
}

/// <summary>
/// 执行sql语句
/// </summary>
/// <param name="sql">sql 语句</param>
/// <param name="parameters">参数</param>
/// <returns></returns>
public IEnumerable<T> FindListBySql(string sql, object dynamic)
{
using (var db = DbFactory.DB)
{
return db.Ado.SqlQuery<T>(sql, dynamic);
}
}

/// <summary>
/// 批量插入 插入失败时 事务会自动回退
/// </summary>
/// <param name="t"></param>
/// <returns></returns>
public int Insert(List<T> t)
{
using (var db = DbFactory.DB)
{
return db.Ado.UseTran(() => db.Insertable(t.ToArray()).ExecuteCommand()).Data;
}
}

/// <summary>
/// 事务
/// </summary>
/// <param name="func"></param>
/// <returns></returns>
public DbResult<T> UserTran(Func<T> func)
{
using (var db = DbFactory.DB)
{
return db.Ado.UseTran(func.Invoke);
}
}

/// <summary>
/// 事务
/// </summary>
/// <param name="action"></param>
public DbResult<bool> UserTran(Action action)
{
using (var db = DbFactory.DB)
{
return db.Ado.UseTran(action.Invoke);
}
}

/// <summary>
/// 根据条件批量删除
/// </summary>
/// <param name="predicate"></param>
/// <returns></returns>
public int DeleteByClause(Expression<Func<T, bool>> predicate)
{
using (var db = DbFactory.DB)
{
return db.Deleteable<T>().Where(predicate).ExecuteCommand();
}
}

// void ShadowCopy(object a, object b);

/// <summary>
/// 分页查询
/// </summary>
/// <param name="predicate"></param>
/// <param name="pagination"></param>
/// <returns></returns>
public List<T> FindList(Expression<Func<T, bool>> predicate, Pagination pagination)
{
var isAsc = pagination.sord.ToLower() == "asc";
string[] _order = pagination.sidx.Split(',');
MethodCallExpression resultExp = null;
using (var db = DbFactory.DB)
{
var tempData = db.Queryable<T>().Where(predicate).ToList().AsQueryable();
foreach (string item in _order)
{
string _orderPart = item;
_orderPart = Regex.Replace(_orderPart, @"\s+", " ");
string[] _orderArry = _orderPart.Split(' ');
string _orderField = _orderArry[0];
bool sort = isAsc;
if (_orderArry.Length == 2)
{
isAsc = _orderArry[1].ToUpper() == "ASC";
}
var parameter = Expression.Parameter(typeof(T), "t");
var property = typeof(T).GetProperty(_orderField);
var propertyAccess = Expression.MakeMemberAccess(parameter, property);
var orderByExp = Expression.Lambda(propertyAccess, parameter);
resultExp = Expression.Call(typeof(Queryable), isAsc ? "OrderBy" : "OrderByDescending", new Type[] { typeof(T), property.PropertyType }, tempData.Expression, Expression.Quote(orderByExp));
}
tempData = tempData.Provider.CreateQuery<T>(resultExp);
pagination.records = tempData.Count();
tempData = tempData.Skip<T>(pagination.rows * (pagination.page - 1)).Take<T>(pagination.rows).AsQueryable();
return tempData.ToList();
}
}
#endregion

#region Async
/// <summary>
/// 查询所有数据(无分页,请慎用)
/// </summary>
/// <returns></returns>
public async Task<IEnumerable<T>> FindAllAsync()
{
using (var db = DbFactory.DB)
{
return await db.Queryable<T>().ToListAsync();
}
}

/// <summary>
/// 根据条件查询数据
/// </summary>
/// <param name="predicate">条件表达式树</param>
/// <param name="orderBy">排序</param>
/// <returns>泛型实体集合</returns>
public async Task<IEnumerable<T>> FindListByClauseAsync(Expression<Func<T, bool>> predicate, string orderBy = "")
{
using (var db = DbFactory.DB)
{
var query = db.Queryable<T>().Where(predicate);
if (!string.IsNullOrEmpty(orderBy))
{
query = query.OrderBy(orderBy);
}
return await query.ToListAsync();
}
}

public async Task<IEnumerable<T>> PageQueryAsync(Expression<Func<T, bool>> predicate, int skip = 0,
int pageSize = 15, string orderBy = "")
{
using (var db = DbFactory.DB)
{
if (skip > 0)
skip = pageSize * skip;
var query = db.Queryable<T>().Where(predicate).Skip(skip).Take(pageSize);
if (!string.IsNullOrEmpty(orderBy))
{
query = query.OrderBy(orderBy);
}
return await query.ToListAsync();
}
}

public async Task<T> FindByClauseAsync(Expression<Func<T, bool>> predicate)
{
using (var db = DbFactory.DB)
{
return await db.Queryable<T>().FirstAsync(predicate);
}
}

/// <summary>
/// 插入实体数据
/// </summary>
/// <param name="entity"></param>
/// <returns></returns>
public async Task<int> InsertAsync(T entity)
{
using (var db = DbFactory.DB)
{
return await db.Insertable(entity).ExecuteCommandAsync();
}
}

/// <summary>
/// 更新实体数据
/// </summary>
/// <param name="entity"></param>
/// <returns></returns>
public async Task<bool> UpdateAsync(T entity)
{
using (var db = DbFactory.DB)
{
return await db.Updateable(entity).ExecuteCommandAsync() > 0;
}
}

/// <summary>
/// DeleteAsync
/// </summary>
/// <param name="entity"></param>
/// <returns></returns>
public async Task<bool> DeleteAsync(T entity)
{
using (var db = DbFactory.DB)
{
return await db.Deleteable(entity).ExecuteCommandAsync() > 0;
}
}

/// <summary>
/// DeleteAsync
/// </summary>
/// <param name="where">条件表达式</param>
/// <returns></returns>
public async Task<bool> DeleteAsync(Expression<Func<T, bool>> @where)
{
using (var db = DbFactory.DB)
{
return await db.Deleteable(@where).ExecuteCommandAsync() > 0;
}
}

/// <summary>
/// DeleteByIdAsync
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
public async Task<bool> DeleteByIdAsync(object id)
{
using (var db = DbFactory.DB)
{
return await db.Deleteable<T>(id).ExecuteCommandAsync() > 0;
}
}

/// <summary>
/// DeleteByIdsAsync
/// </summary>
/// <param name="ids">ids</param>
/// <returns></returns>
public async Task<bool> DeleteByIdsAsync(object[] ids)
{
using (var db = DbFactory.DB)
{
return await db.Deleteable<T>().In(ids).ExecuteCommandAsync() > 0;
}
}

/// <summary>
/// InsertAsync
/// </summary>
/// <param name="t"></param>
/// <returns></returns>
public async Task<DbResult<Task<int>>> InsertAsync(List<T> t)
{
using (var db = DbFactory.DB)
{
return await db.Ado.UseTranAsync(async () => await db.Insertable(t.ToArray()).ExecuteCommandAsync());
}
}

/// <summary>
/// DeleteByClauseAsync
/// </summary>
/// <param name="predicate"></param>
/// <returns></returns>
public async Task<int> DeleteByClauseAsync(Expression<Func<T, bool>> predicate)
{
using (var db = DbFactory.DB)
{
return await db.Deleteable<T>().Where(predicate).ExecuteCommandAsync();
}
}

/// <summary>
/// 事务
/// </summary>
/// <param name="func"></param>
/// <returns></returns>
public async Task<DbResult<T>> UserTranAsync(Func<T> func)
{
using (var db = DbFactory.DB)
{
return await db.Ado.UseTranAsync(func.Invoke);
}
}

/// <summary>
/// 事务
/// </summary>
/// <param name="action"></param>
public async Task<DbResult<bool>> UserTranAsync(Action action)
{
using (var db = DbFactory.DB)
{
return await db.Ado.UseTranAsync(action.Invoke);
}
}
#endregion
}

本篇就到这里，下篇将介绍业务逻辑层与仓储库之间的关系与实现

（本人坚信：学习是由浅到深的过程，先打基础）

　　不喜勿喷！谢谢！

GitHub地址：

　　https://github.com/AjuPrince/Aju.Carefree