/// <summary>
/// 是否存在数据
/// </summary>
/// <param name="lambda">查询表达式</param>
/// <returns>是否存在数据</returns>
public bool Any(Expression <Func <TEntity, bool> > lambda)
{
var convert = PredicateConvert.Convert(Fields, lambda);
using (SqliteDataBaseScope.CreateScope(this.DataBase))
{
return(this.ExistInner(convert.ConditionSql, convert.Parameters));
}
}
/// <summary>
/// 载入首行
/// </summary>
/// <param name="lambda">查询表达式</param>
/// <returns>如果有载入首行,否则返回空</returns>
public TEntity FirstOrDefault(Expression <Func <TEntity, bool> > lambda)
{
var convert = PredicateConvert.Convert(Fields, lambda);
return(LoadFirst(convert.ConditionSql, convert.Parameters));
}
/// <summary>
/// 分析Lambda表达式
/// </summary>
/// <typeparam name="T">方法类型</typeparam>
/// <param name="columns">关联字段</param>
/// <param name="predicate">Lambda表达式</param>
/// <returns></returns>
public static ConditionItem Convert <T>(string[] columns, Expression <T> predicate)
{
var convert = new PredicateConvert(columns);
return(convert.Convert(predicate));
}
