Repository Layer

nicyeNovember 21, 2021About 4 minAbout 1121 words

Repository Layer

As an extension, FreeSql.Repository realizes the functions of the common DAL. There is a certain standard definition for the repository layer. FreeSql.Repository refers to the interface design of Abp vNext, defines and implements the basic repository layer for CURD operations.


  • Select/Attach: Snapshot object, the corresponding Update only updates the changed fields.
  • Insert: Insert data, adapt to each database to optimize execution ExecuteAffrows, ExecuteIdentity or ExecuteInserted;
  • InsertOrUpdate: Insert or update data.
  • SaveMany: Quickly save navigation objects (one-to-many, many-to-many).


Situation 1: .NET Core or .NET 5.0+

dotnet add package FreeSql.Repository

Situation 2、.NET Framework

Install-Package FreeSql.DbContext


static IFreeSql fsql = new FreeSql.FreeSqlBuilder()
    .UseConnectionString(FreeSql.DataType.Sqlite, connectionString)
    //Automatically synchronize the entity structure to the database.
    //Be sure to define as singleton mode

public class Song {
    [Column(IsIdentity = true)]
    public int Id { get; set; }
    public string Title { get; set; }


Method 1. The extension method of IFreeSql

var curd = fsql.GetRepository<Song>();

Note: Repository objects are not safe under multiple threads, so you should not operate them on multiple threads at the same time.

  • Does not support using the same repository instance in different threads at the same time

Method 2. Inheritance

public class SongRepository : BaseRepository<Song, int> {
    public SongRepository(IFreeSql fsql) : base(fsql, null, null) {}

    //Do something except CURD. 

Method 3: Dependency Injection

public void ConfigureServices(IServiceCollection services) {
    services.AddFreeRepository(filter => filter
        .Apply<ISoftDelete>("SoftDelete", a => a.IsDeleted == false)
        .Apply<ITenant>("Tenant", a => a.TenantId == 1)

//Use in the controller
public SongsController(IBaseRepository<Song> repos1) {

Dependency injection can realize the global setting of filtering and verification, which is convenient for the design of tenant functions.

For more information: 《Filters and Global Filters》

State Management

Only update the changed properties:

var repo = fsql.GetRepository<Topic>();
var item = repo.Where(a => a.Id == 1).First();  //Take a snapshot of item at this time
item.Title = "newtitle";
repo.Update(item); //Compare with snapshots to get changes

//UPDATE `tb_topic` SET `Title` = @p_0
//WHERE (`Id` = 1)

Or further streamline:

var repo = fsql.GetRepository<Topic>();
var item = new Topic { Id = 1 };
repo.Attach(item); //Take a snapshot of item at this time
item.Title = "newtitle";
repo.Update(item); //Compare with snapshots to get changes

//UPDATE `tb_topic` SET `Title` = @p_0
//WHERE (`Id` = 1)

Filtering and Verification

Suppose we have two entities: User and Topic, and two repositories are defined in the domain class:

var userRepository = fsql.GetGuidRepository<User>();
var topicRepository = fsql.GetGuidRepository<Topic>();

In practice, we always worry about the data security of topicRepository, that is, it is possible to query or change the topic of other users. Therefore, we have made improvements in the v0.0.7 version, adding the filter lambda expression parameter.

var userRepository = fsql.GetGuidRepository<User>(a => a.Id == 1);
var topicRepository = fsql.GetGuidRepository<Topic>(a => a.UserId == 1);
  • Attach this condition when querying/modifying/deleting, so that the data of other users will not be modified.
  • When adding, use expressions to verify the legality of the data, if not legal, an exception will be thrown.

Sharding Tables and Database

FreeSql provides a basic method of sharding tables through AsTable. As a distributed repository, and GuidRepository as a distributed storage, realizes the encapsulation of sharding tables and database (cross-server sharding-database is not supported).

var logRepository = fsql.GetGuidRepository<Log>(null, oldname => $"{oldname}_{DateTime.Now.ToString("YYYYMM")}");

Above we got a log repository, which corresponds to the shareding-table by year and month. Using CURD operation will finally take effect in the Log_201903 table.


  • Versions after v0.11.12 can use CodeFirst to migrate sharding tables.
  • Do not use lazy loading in the entity type of sharding tables and database.

Compatibility Problems

The output inserted feature provided by SqlServer. When the table uses auto-increment or the database defines a default value, use this feature to quickly return the inserted data. PostgreSQL also has similar functions, but not every database supports it.

When a database that does not support this feature (Sqlite/MySql/Oracle/Damen/MsAccess) is used, and the entity uses auto-increment attributes, the batch insertion of the repository will be executed one by one. The following improvements can be considered:

  • Use uuid as the primary key (ie Guid).
  • Avoid using the default value function of the database.

Cascade Saving

Please view the documentation of Cascade Saving.


EntityTypeTypeThe entity type that the repository is operating. Note that it is not necessarily TEntity
UnitOfWorkIUnitOfWorkUnit of work currently in use
OrmIFreeSqlORM currently in use
DbContextOptionsDbContextOptionsDbContext settings currently in use,modifying the DbContextOptions will not affect other repository.
DataFilterIDataFilter<TEntity>Repository Filter, valid in this object
SelectISelect<TEntity>Prepare to query data
AsTypevoidTypeChange the type of entity that the repository is operating
GetTEntityTKeyQuery data by the primary key
FindTEntityTKeyQuery data by the primary key
DeleteintTKeyDelete data by the primary key
DeleteintLambdaDelete data by lambda conditions
DeleteintTEntityQuery entity
DeleteintIEnumerable<TEntity>Delete data in bulk
DeleteCascadeByDatabaseList<object>LambdaRecursively delete data from the database according to navigation attributes
Insert-TEntityInsert data, if the entity has an auto-increment column, the auto-increment after insertion will be filled into the entity
Insert-IEnumerable<TEntity>Insert data in bulk
Update-TEntityUpdate entity
Update-IEnumerable<TEntity>Update data in bulk
InsertOrUpdate-TEntityInsert ot update data in bulk
FlushState--Clear status information
Attach-TEntityAttach entities to state management, which can be used to update or delete without querying
Attach-IEnumerable<TEntity>Batch attach entities to state management
AttachOnlyPrimary-TEntityOnly attach the primary key data of the entity to the state management
SaveMany-TEntity, stringSave the specified many-to-many or one-to-many navigation properties of the entity (full comparison)
BeginEdit-List<TEntity>Start editing the data of a set of entities
EndEditint-After a set of data is edited, save it

State management can realize that Update only updates the changed fields (not all fields), and it is very comfortable to use Attach and Update flexibly.