/// <summary>
/// 使用主键值查询返回一个实体。
/// </summary>
/// <param name="primaryValues">主键的值。数组的长度必须与实体所定义的主键相匹配。</param>
/// <param name="func">对实体对象进行修饰的方法。</param>
/// <returns>一个实体对象。</returns>
public IEntity First(object[] primaryValues, Func <object, object> func)
{
if (primaryValues == null || primaryValues.Length == 0)
{
return(null);
}
var parameters = new ParameterCollection();
var context = CreateContext(parameters);
var sql = EntityPersistentQueryBuilder.BuildGetFirstQuery(context, entityType, primaryValues);
if (sql.IsNullOrEmpty())
{
return(null);
}
var mapper = RowMapperFactory.CreateMapper(entityType);
mapper.RecordWrapper = database.Provider.GetService <IRecordWrapper>();
using (var reader = database.ExecuteReader(sql, parameters: parameters))
{
if (reader.Read())
{
return(func(mapper.Map(reader).InitializeEnvironment(environment)) as IEntity);
}
}
return(null);
}
/// <summary>
/// 执行一个查询，返回一个序列。
/// </summary>
/// <param name="database"></param>
/// <param name="elementType"></param>
/// <param name="queryCommand"></param>
/// <param name="segment"></param>
/// <param name="parameters"></param>
/// <param name="initializer"></param>
/// <param name="setter"></param>
/// <returns></returns>
internal static IEnumerable InternalExecuteEnumerable(this IDatabase database, Type elementType, IQueryCommand queryCommand, IDataSegment segment = null, ParameterCollection parameters = null, Action <object> initializer = null, Action <IDataReader, object> setter = null)
{
var mapper = RowMapperFactory.CreateMapper(elementType);
Guard.ArgumentNull(mapper, "mapper");
mapper.RecordWrapper = database.Provider.GetService <IRecordWrapper>();
mapper.Initializer = initializer;
using (var reader = database.ExecuteReader(queryCommand, segment, parameters))
{
while (reader.Read())
{
var item = mapper.Map(reader);
setter?.Invoke(reader, item);
yield return(item);
}
}
}