/// <summary>
/// 通过主键和指定类型从数据库获取对象
/// </summary>
/// <typeparam name="T">指定类型</typeparam>
/// <param name="keyValue">主键值（通常为Guid），不能为空</param>
/// <returns>从数据库中得到的对象,如果数据库中没找到对象会返回一个空对象</returns>
/// 前置条件
/// 1.keyValue不能为空
/// 2.传入的对象T只能有一个主键
public T GetByKey <T>(object keyValue)
where T : new()
{
PreconditionAssert.IsNotNull(keyValue, ErrorMessages.NullReferenceException);
ORMHelper.EntityIsMappingDatabase(typeof(T), ErrorMessages.EntityMappingError);
SelectCommandCreator dbCommandCreator = new SelectCommandCreator(_dbAccess);
dbCommandCreator.ObjectType = typeof(T);
dbCommandCreator.KeyValue = keyValue;
dbCommandCreator.SelectType = SelectType.GetOneByKeyValue;
DbCommand dbCommand = dbCommandCreator.GetDbCommand();
DataTable dt = _dbAccess.GetDataTableByCommand(dbCommand);
if (dt.Rows.Count == 0)
{
return(default(T));
}
else if (dt.Rows.Count == 1)
{
return(ORMHelper.ConvertDataRowToEntity <T>(dt.Rows[0]));
}
else
{
//引发数据获取结果错误
throw new ORMException(ErrorMessages.ResultNotUniqueMessage);
}
}
/// <summary>
/// 通过对象已有的主键值（可以多个主键）和指定类型从数据库获取对象
/// </summary>
/// <typeparam name="T">指定类型</typeparam>
/// <param name="entity">外部构造的对象，不能为空</param>
/// <returns>从数据库中得到的对象,如果数据库中没找到对象会返回一个空对象</returns>
/// 前置条件
/// 传入的entity对象不能为空
public T GetByKeys <T>(T entity) where T : new()
{
PreconditionAssert.IsNotNull(entity, ErrorMessages.NullReferenceException);
ORMHelper.EntityIsMappingDatabase(entity.GetType(), ErrorMessages.EntityMappingError);
ORMHelper.CheckEntityKey(entity);
SelectCommandCreator dbCommandCreator = new SelectCommandCreator(_dbAccess);
dbCommandCreator.Entity = entity;
dbCommandCreator.SelectType = SelectType.GetOneByEntityKey;
DbCommand dbCommand = dbCommandCreator.GetDbCommand();
DataTable dt = _dbAccess.GetDataTableByCommand(dbCommand);
if (dt.Rows.Count == 0)
{
return(default(T));
}
else if (dt.Rows.Count == 1)
{
return(ORMHelper.ConvertDataRowToEntity <T>(dt.Rows[0]));
}
else
{
throw new ORMException(ErrorMessages.ResultNotUniqueMessage);
}
}
/// <summary>
/// 获取数据库中所有的数据总数
/// </summary>
/// <typeparam name="T">指定类型</typeparam>
/// <returns>数据总数</returns>
public int GetAllCount <T>()
{
ORMHelper.EntityIsMappingDatabase(typeof(T), ErrorMessages.EntityMappingError);
SelectCommandCreator dbCommandCreator = new SelectCommandCreator(_dbAccess);
dbCommandCreator.ObjectType = typeof(T);
dbCommandCreator.SelectType = SelectType.GetAllCount;
DbCommand dbCommand = dbCommandCreator.GetDbCommand();
return((int)_dbAccess.GetRC1ByCommand(dbCommand));
}
/// <summary>
/// 修改一个数据库中已有的对象，该对象的主键必须有值
/// 该对象为空或主键为空或修改失败会抛出异常
/// </summary>
/// <param name="entity">需要修改的实体对象</param>
/// 前置条件
/// 参数entity不允许为空
public void Modify(object entity)
{
//断言参入的参数为null或者空字符串（RErrorCode.NullReference - 0x00000001）
PreconditionAssert.IsNotNull(entity, ErrorMessages.NullReferenceException);
ORMHelper.EntityIsMappingDatabase(entity.GetType(), ErrorMessages.EntityMappingError);
ORMHelper.CheckEntityIsNotReadOnly(entity.GetType(), ErrorMessages.EntityReadOnly);
ModifyCommandCreator mcc = new ModifyCommandCreator(_dbAccess);
mcc.Entity = entity;
DbCommand dbCommand = mcc.GetDbCommand();
_dbAccess.ExecCommand(dbCommand);
}
/// <summary>
/// 通过指定类型,过滤条件和排序方式从数据库中获取该指定类型的数据条数
/// </summary>
/// <param name="entity">实体对象</param>
/// <param name="filterProterties">过滤条件</param>
/// <returns>指定类型的数据条数</returns>
/// 前置条件
/// 传入的参数entity不允许为空
/// filterProterties,orderBy可以为空，如果为空则没有where条件查询和不进行排序
public int GetCount(object entity, string[] filterProterties)
{
//断言传入的entity对象为null或者为空字符串，出现空引用异常
PreconditionAssert.IsNotNull(entity, ErrorMessages.NullReferenceException);
ORMHelper.EntityIsMappingDatabase(entity.GetType(), ErrorMessages.EntityMappingError);
SelectCommandCreator dbCommandCreator = new SelectCommandCreator(_dbAccess);
dbCommandCreator.Entity = entity;
dbCommandCreator.FilterProterties = filterProterties;
dbCommandCreator.SelectType = SelectType.GetCount;
DbCommand dbCommand = dbCommandCreator.GetDbCommand();
return((int)_dbAccess.GetRC1ByCommand(dbCommand));
}
/// <summary>
/// 获取数据表中的所有数据集合，并按指定排序方式进行排序
/// </summary>
/// <typeparam name="T">指定的类型</typeparam>
/// <param name="orderBy">排序方式</param>
/// <returns>数据表中的所有数据集合</returns>
/// 前置条件
/// 传入的orderBy对象可以为空，为空的时候则不进行排序
public IList <T> GetAll <T>(params SortInfo[] orderBy) where T : new()
{
PreconditionAssert.IsNotNull(orderBy, ErrorMessages.NullReferenceException);
ORMHelper.EntityIsMappingDatabase(typeof(T), ErrorMessages.EntityMappingError);
SelectCommandCreator dbCommandCreator = new SelectCommandCreator(_dbAccess);
dbCommandCreator.ObjectType = typeof(T);
dbCommandCreator.OrderBy = orderBy;
dbCommandCreator.SelectType = SelectType.GetAll;
DbCommand dbCommand = dbCommandCreator.GetDbCommand();
DataTable dt = _dbAccess.GetDataTableByCommand(dbCommand);
return(ORMHelper.DataTableToList <T>(dt));
}
/// <summary>
/// 通过指定类型,过滤条件和排序方式从数据库中获取该指定类型的数据集合
/// </summary>
/// <typeparam name="T">指定类型</typeparam>
/// <param name="entity">实体对象</param>
/// <param name="filterProterties">字段名称，可包含多个</param>
/// <param name="orderBy">排序方式</param>
/// <returns>指定类型的数据集合</returns>
/// 前置条件
/// 传入的参数entity，filterProterties不允许为空
/// orderBy可以为空，如果为空则不进行排序
public IList <T> GetList <T>(T entity, string[] filterProterties, params SortInfo[] orderBy)
where T : new()
{
//断言传入的entity对象为null或者为空字符串，出现空引用异常
PreconditionAssert.IsNotNull(entity, ErrorMessages.NullReferenceException);
PreconditionAssert.IsNotNull(filterProterties, ErrorMessages.NullReferenceException);
ORMHelper.EntityIsMappingDatabase(entity.GetType(), ErrorMessages.EntityMappingError);
SelectCommandCreator dbCommandCreator = new SelectCommandCreator(_dbAccess);
dbCommandCreator.Entity = entity;
dbCommandCreator.FilterProterties = filterProterties;
dbCommandCreator.OrderBy = orderBy;
dbCommandCreator.SelectType = SelectType.GetList;
DbCommand dbCommand = dbCommandCreator.GetDbCommand();
DataTable dt = _dbAccess.GetDataTableByCommand(dbCommand);
return(ORMHelper.DataTableToList <T>(dt));
}