FreeSql (xxi) query returns data

FreeSql using ExpressionTree optimize reading speed reading, if you must know to understand the technology in addition to native code, Emit is the fastest and ExpressionTree under .NETCore technology.

Reflecting the project during the initial period of + cache, although .NETCore optimize the performance of reflection, but after the Dapper performance comparison test and found that there are still some gaps, into ExpresstionTree after the Dapper performance considerably.

FreeSql supported types are more ExpressionTree achieve greater complexity, friends who are interested can read the source code.

IFreeSql fsql = new FreeSql.FreeSqlBuilder()
    .UseConnectionString(FreeSql.DataType.MySql, "Data Source=127.0.0.1;Port=3306;User ID=root;Password=root;Initial Catalog=cccddd;Charset=utf8;SslMode=none;Max pool size=10")
    .Build();

[Table(Name = "tb_topic")]
class Topic {
    [Column(IsIdentity = true, IsPrimary = true)]
    public int Id { get; set; }
    public int Clicks { get; set; }
    public int TestTypeInfoGuid { get; set; }
    public TestTypeInfo Type { get; set; }
    public string Title { get; set; }
    public DateTime CreateTime { get; set; }
}
class TestTypeInfo {
    public int Guid { get; set; }
    public int ParentId { get; set; }
    public TestTypeParentInfo Parent { get; set; }
    public string Name { get; set; }
}
class TestTypeParentInfo {
    public int Id { get; set; }
    public string Name { get; set; }
}

ISelect<Topic> select => fsql.Select<Topic>();

Returns a single record

Topic t1 = select.Where(a => a.Id == 1).ToOne();

FreeSql a convention, ToOne always return null object data or entity, ToList always returns a non-null List <entity type>

Return List

List<Topic> t1 = select.Where(a => a.Id > 0).Skip(100).Limit(200).ToList();

Back List + navigation data attributes

List<Topic> t2 = select.LeftJoin(a => a.Type.Guid == a.TestTypeInfoGuid).ToList();
//此时会返回普通字段 + 导航对象 Type 的数据

Returns the specified field

//返回一个字段
List<int> t3 = select.Where(a => a.Id > 0).ToList(a => a.Id);

//返回匿名类
List<匿名类> t4 = select.Where(a => a.Id > 0).ToList(a => new { a.Id, a.Title });

//返回元组
List<(int, string)> t5 = select.Where(a => a.Id > 0).ToList<(int, string)>("id, title");

//返回指定映射字段
List<(int, string)> t6 = select.Where(a => a.Id > 0).ToList<Dto>();

//返回SQL字段
List<匿名类> t7 = select.Where(a => a.Id > 0).Skip(100).Limit(200)
    .ToList(a => new {
        a.Id,
        a.Title,
        cstitle = "substr(a.title, 0, 2)", //将 substr(a.title, 0, 2) 作为查询字段
        csnow = Convert.ToDateTime("now()"), //将 now() 作为查询字段
        //奇思妙想：怎么查询开窗函数的结果
    });

//返回更为复杂的结构
List<匿名类> t8 = select.From<TestTypeInfo, TestTypeParentInfo>((s, b, c) => s
    .InnerJoin(a => a.TypeGuid == b.Guid)
    .LeftJoin(a => c.Id == b.ParentId)
    .Where(a => b.Name != "xxx")).ToList((a, b, c) => new {
        a.Id,
        a.Title,
        a.Type,
        ccc = new { a.Id, a.Title },
        tp = a.Type,
        tp2 = new {
            a.Id,
            tp2 = a.Type.Name
        },
        tp3 = new {
            a.Id,
            tp33 = new {
                a.Id
            }
        }
    });

SQL execution

class xxx {
    public int Id { get; set; }
    public string Path { get; set; }
    public string Title2 { get; set; }
}

List<xxx> t9 = fsql.Ado.Query<xxx>("select * from song");
List<(int, string ,string)> t10 = fsql.Ado.Query<(int, string, string)>("select * from song");
List<dynamic> t11 = fsql.Ado.Query<dynamic>("select * from song");

Using AsTable

var t12 = fsql.Select<User>()
    .AsTable((a, b) => "(select * from tb_topic where clicks > 10)")
    .Page(1, 10).ToList()

ToChunk

Executing the query, the returned data block, reduce memory overhead. 100000 such as reading of data, each processing 100 returns.

var testlist1 = fsql.Select<Song>().OrderBy(a => a.Id).ToList();
var testlist2 = new List<Song>();
fsql.Select<Song>().OrderBy(a => a.Id).ToChunk(100, list =>
{
    testlist2.AddRange(list);
});
//这里示范，最终 testlist1 与 testlist2 返回的数据相同。

API

method	return value	parameter	description
ToSql	string		Returns the SQL statement to be executed
ToList	List		Execute SQL query and returns all fields of record T1 entity, if the navigation attribute exists with query returns Count returns, there is no record of when the list 0
ToList<Dto>	List<Dto>	Lambda	Execute SQL query and returns the specified field or Dto mapping record, Count returned when there is no record list 0
ToList<T>	List<T>	string field	Executing the SQL query, returns the specified field recording field, and tuple or base type (int, string, long) receiving, recording absence Count returned list 0
ToOne	T1		Executing the SQL query, returns the first record all the fields T1 entity, or null when there is no record
ToChunk	<Empty>	int size, Action<List<T1>> done	Executing the SQL query, the returned data block, reduce memory overhead. 100000 such as reading of data, each processing 100 returns.
Any	bool		Execute SQL queries, whether there is record
Sum	T	Lambda	Specify a column summation
me	T	Lambda	Specify a column for the minimum
Max	T	Lambda	Specify a column selecting the maximum value
Avg	T	Lambda	Specify a column averaging