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Greed Loading
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ManyToOne/OneToOne navigation properties are loaded by ToList(includeNestedMembers: false), parameter description:
false: Return the navigation data of Level 2 Join (default);
true: Return the navigation data of all levels of depth Join (unused navigation data will not be returned).
Select<Tag>().Include(a => a.Parent.Parent).ToList(true); Select<Tag>().Where(a => a.Parent.Parent.Name == "1").ToList(true); //Write in this way, no need to mark Join, //it will be automatically processed into LeftJoin when parsing the expression Select<Tag>().LeftJoin(a => a.Parent.Id == a.ParentId && a.Parent.xxx > 0).ToList(); //Write this way to add filtering conditions to ManyToOneIncludeMany greedily loads the navigation properties of the collection. In fact, it is queried twice, and data is assembled after ToList.
Select<Tag>().IncludeMany(a => a.Songs).ToList(); Select<Tag>().IncludeMany(a => a.Songs, then => then.Where(song => song.xxx > 0)).ToList(); //Write this way to add filtering conditions to OneToMany/ManyToManyIncludeMany has a second parameter, which can be modified before the second query.
Select<Tag>().IncludeMany(a => a.Songs, then => then.Where(song => song.User == "admin")).ToList();In fact, in Then, you can continue to use Include/IncludeMany. As long as you like it, it’s okay to go down 100 levels.
IncludeByPropertyName realize dynamic Include/IncludeMany
It can also be greedily loaded without configuring the navigation relationship.
Select<Tag>().IncludeMany(a => a.TestManys.Where(b => b.TagId == a.Id));Only query the first few pieces of data in each sub-collection to avoid poor IO performance caused by loading all data like EfCore (for example, there are 2000 comments under a product).
Select<Tag>().IncludeMany(a => a.TestManys.Take(10));The sub-collection returns a part of the fields to avoid the problem of too many fields.
Select<Tag>().IncludeMany(a => a.TestManys.Select(b => new TestMany { Title = b.Title ... }));When the main data already exists in the memory, how to load the sub-data? So we added the List<T> extension method, the example is as follows:
new List<Song>(new[] { song1, song2, song3 }) .IncludeMany(fsql, a => a.Tags);new List<Song>(new[] { song1, song2, song3 }) .IncludeByPropertyName( orm: fsql, property: "Tags", where: "ParentId=Code", take: 5, select: "id,name", then => then.IncludeByPropertyName("Parent") ); //v3.2.605+v3.2.650+
fsql.Select<Topic>().ToList(a => new { all = a, list1 = fsql.Select<T2>().ToList(), list2 = fsql.Select<T2>().Where(b => b.TopicId == a.Id).ToList() }); fsql.Select<Topic>() .GroupBy(a => new { a.Author }) .WithTempQuery(a => new { Author = a.Key.Author, Count = a.Count() }) .ToList(a => new { a.Author, a.Count, list1 = fsql.Select<T2>().ToList(), list2 = fsql.Select<T2>().Where(b => b.Author == a.Author).ToList() });Way 1: IncludeMany extensions
var list = fsql.Select<SysModule>() .Page(1, 10) .ToList(a => new { Id = a.Id }) //Query data id .Select(a => new SysModule { Id = a.Id }).ToList() //Memory operation .IncludeMany(fsql, a => a.Permissions, then => then.Include(a => a.Button));SELECT a."Id" as1 FROM "SysModule" a limit 0,10 SELECT a."Id", a."SysModuleId", a."SysModuleButtonId", a."Status", a__Button."Id" as5, a__Button."Name", a__Button."EventName", a__Button."EnCode", a__Button."Icon", a__Button."Sort", a__Button."CreateTime" FROM "SysModulePermission" a LEFT JOIN "SysModuleButton" a__Button ON a__Button."Id" = a."SysModuleButtonId" WHERE ((a."SysModuleId") in ('menu1','menu2'))Way 2: Directly IncludeMany + ToList
var list = fsql.Select<SysModule>() .IncludeMany(m => m.Permissions, then => then.Include(a => a.Button)) .Page(1, 10) .ToList();SELECT a."Id", a."ParentId", a."Name", a."Icon", a."UrlAddress", a."IsShow", a."Sort", a."Description", a."CreateTime" FROM "SysModule" a limit 0,10 SELECT a."Id", a."SysModuleId", a."SysModuleButtonId", a."Status", a__Button."Id" as5, a__Button."Name", a__Button."EventName", a__Button."EnCode", a__Button."Icon", a__Button."Sort", a__Button."CreateTime" FROM "SysModulePermission" a LEFT JOIN "SysModuleButton" a__Button ON a__Button."Id" = a."SysModuleButtonId" WHERE ((a."SysModuleId") in ('menu1','menu2'))Case: Query Vod table, 10 data for each of category 1, category 2, and category 3
class Vod { public Guid Id { get; set; } public int TypeId { get; set; } } //Define a temporary class, it can also be a DTO class Dto { public int TypeId { get; set; } public List<Vod> Vods { get; set; } } var dto = new [] { 1,2,3 }.Select(a => new Dto { TypeId = a }).ToList(); dto.IncludeMany(fsql, d => d.Vods.Take(10).Where(vod => vod.TypeId == d.TypeId)); //After execution, each element.Vods of DTO will only have 10 records