/// <summary>
/// 执行查询，并返回单个对象
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="queryModel"></param>
/// <param name="returnDefaultWhenEmpty"></param>
/// <returns></returns>
public T ExecuteSingle <T>(QueryModel queryModel, bool returnDefaultWhenEmpty)
{
MySqlQueryModelVisitor queryModelVisitor = new MySqlQueryModelVisitor();
var command = queryModelVisitor.Translate(queryModel);
this.provider.ExecutedCommandBuilder = command;
using (IDataReader reader = this.provider.ExecuteDataReader(command))
{
bool isExists = reader.Read();
// 如果不存在查询记录
if (isExists == false)
{
// 如果可以默认
if (returnDefaultWhenEmpty)
{
return(default(T));
}
else
{
throw new InvalidOperationException("未查询出满足条件的任何记录。");
}
}
var tuple = reader.GetDeserializerState <T>();
return((T)tuple.Func(reader));
}
}
/// <summary>
/// 执行查询，并返回第一行第一列
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="queryModel"></param>
/// <returns></returns>
public T ExecuteScalar <T>(QueryModel queryModel)
{
MySqlQueryModelVisitor queryModelVisitor = new MySqlQueryModelVisitor();
var command = queryModelVisitor.Translate(queryModel);
this.provider.ExecutedCommandBuilder = command;
return(this.provider.ExecuteScalar <T>(command));
}
/// <summary>
/// 执行查询，并返回第一行第一列
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="queryModel"></param>
/// <returns></returns>
public T ExecuteScalar <T>(QueryModel queryModel)
{
MySqlQueryModelVisitor queryModelVisitor = new MySqlQueryModelVisitor();
var command = queryModelVisitor.Translate(queryModel);
SqlCmd.Current = command;
return(this.provider.ExecuteScalar <T>(command.Sql, command.Parameters));
}
/// <summary>
/// 执行查询，并返回 IEnumerable<T> 对象
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="queryModel"></param>
/// <returns></returns>
public IEnumerable <T> ExecuteCollection <T>(QueryModel queryModel)
{
MySqlQueryModelVisitor queryModelVisitor = new MySqlQueryModelVisitor();
var command = queryModelVisitor.Translate(queryModel);
this.provider.ExecutedCommandBuilder = command;
using (IDataReader reader = this.provider.ExecuteDataReader(command))
{
var tuple = reader.GetDeserializerState <T>();
while (reader.Read())
{
yield return((T)tuple.Func(reader));
}
}
}
/// <summary>
/// 执行查询，并返回 IEnumerable<T> 对象
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="queryModel"></param>
/// <returns></returns>
public IEnumerable <T> ExecuteCollection <T>(QueryModel queryModel)
{
MySqlQueryModelVisitor queryModelVisitor = new MySqlQueryModelVisitor();
var command = queryModelVisitor.Translate(queryModel);
SqlCmd.Current = command;
using (IDataReader reader = this.provider.ExecuteDataReader(command.Sql.ToString(), command.Parameters))
{
var tuple = reader.GetDeserializerState <T>();
while (reader.Read())
{
yield return((T)tuple.Func(reader));
}
}
}
/// <summary>
/// 执行查询，并返回单个对象
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="queryModel"></param>
/// <param name="returnDefaultWhenEmpty"></param>
/// <returns></returns>
public T ExecuteSingle <T>(QueryModel queryModel, bool returnDefaultWhenEmpty)
{
MySqlQueryModelVisitor queryModelVisitor = new MySqlQueryModelVisitor();
var command = queryModelVisitor.Translate(queryModel);
this.provider.ExecutedCommandBuilder = command;
using (IDataReader reader = this.provider.ExecuteDataReader(command))
{
if (reader.Read() == false && returnDefaultWhenEmpty)
{
return(default(T));
}
var tuple = reader.GetDeserializerState <T>();
return((T)tuple.Func(reader));
}
}