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layout default
sidebar references
title Connection-Based Repository
nav_order 2
permalink /reference/connectionrepository
tags
repodb
connectionrepository
parent REFERENCES

Connection-Based Repository

This page contains the reference implementation when implementing a repository that is using a connection object per method. The consolidated output of this page can be found here.

{: .important }

This kind of repository is direct and is usually unstructured. Use this repository if you are in minimal development.

Recommended Objects (Optional)

Recommended Properties (Optional)

Cache

Create a custom cache class.

public static class MyCustomCache : MemoryCache
{
    ...
}

Create a factory class.

public static class CacheFactory
{
    private static object _syncLock = new object();
    private static ICache _cache = null;
    
    public static ICache CreateCacher()
    {
        if (_cache == null)
        {
            lock (_syncLock)
            {
                if (_cache == null)
                {
                    _cache = new MyCustomCache();
                }
            }
        }
        return _cache;
    }
}

Or, if you wish to dependency inject.

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();

    // Registration
    services.AddSingleton<ICache, MyCustomCache>();
}

Trace

Create a custom trace class.

public static class MyCustomTrace : ITrace
{
    /* Implement all the methods here */
}

Create a factory class.

public static class TraceFactory
{
    private static object _syncLock = new object();
    private static ITrace _trace = null;
    
    public static ITrace CreateTracer()
    {
        if (_trace == null)
        {
            lock (_syncLock)
            {
                if (_trace == null)
                {
                    _trace = new MyCustomTrace();
                }
            }
        }
        return _trace;
    }
}

Or, if you wish to dependency inject.

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();

    // Registration
    services.AddSingleton<ITrace, MyCustomTrace>();
}

Settings

The settings object must be injected within the constructor of the repository. Please refer to Microsoft documentation.

public class AppSetting
{
    public string ConnectionString { get; set; }
    public int CommandTimeout { get; set; }
    public int CacheItemExpiration { get; set; }
}

Repository

Below is the sample repository implementation.

For the factory classes.

public class NorthwindRepository
{
    private IOptions<AppSettings> _settings;

    public RepositoryBase(IOptions<AppSetting> settings)
    {
        _settings = settings;
        Cache = CacheFactory.CreateCacher();
        Trace = TraceFactory.CreateTracer();
    }

    /*** Properties ***/

    public ITrace Trace { get; }

    public ICache Cache { get; }

    ...
}

For the dependency-injected classes.

public class NorthwindRepository
{
    private IOptions<AppSettings> _settings;

    public RepositoryBase(IOptions<AppSetting> settings,
        ICache cache,
        ITrace trace)
    {
        _settings = settings;
        Cache = cache;
        Trace = trace;
    }

    /*** Properties ***/

    public ITrace Trace { get; }

    public ICache Cache { get; }

    ...
}

Operational Methods

Below is the recommended way when exposing a method that return the records.

public IEnumerable<Customer> GetCustomers(string cacheKey = null)
{
    using (var connection = CreateConnection())
    {
        return connection.QueryAll<Customer>(cacheKey: cacheKey,
            commandTimeout: _settings.CommandTimeout,
            cache: Cache,
            cacheItemExpiration: _settings.CacheItemExpiration,
            trace: Trace);
    }
}

Below is the recommended way when exposing a method that returns a single record.

public Customer GetCustomer(int id)
{
    using (var connection = CreateConnection())
    {
        return connection.Query<Customer>(id,
            commandTimeout: _settings.CommandTimeout,
            trace: Trace);
    }
}

Below is the recommended way when exposing a method that deletes a record.

public int DeleteCustomer(int id)
{
    using (var connection = CreateConnection())
    {
        return connection.Delete<Customer>(id,
            commandTimeout: _settings.CommandTimeout,
            trace: Trace);
    }
}

Below is the recommended way when exposing a method that merges a record.

public int MergeCustomer(Customer entity)
{
    using (var connection = CreateConnection())
    {
        return connection.Merge<Customer, int>(entity,
            commandTimeout: _settings.CommandTimeout,
            trace: Trace);
    }
}

Below is the recommended way when exposing a method that saves a record.

public int SaveCustomer(Customer entity)
{
    using (var connection = CreateConnection())
    {
        return connection.Insert<Customer, int>(entity,
            commandTimeout: _settings.CommandTimeout,
            trace: Trace);
    }
}

Below is the recommended way when exposing a method that updates a record.

public int UpdateCustomer(Customer entity)
{
    using (var connection = CreateConnection())
    {
        return connection.Update<Customer>(entity,
            trace: Trace);
    }
}

Async Methods

Ensure that all the synchronous methods you had created has the corresponding asynchronous methods suffixed by Async keyword. Within these methods, ensure that you are calling the corresponding asynchronous operations of the library.

// Get (Many)

public async Task<IEnumerable<Customer>> GetCustomersAsync(string cacheKey = null)
{
    using (var connection = CreateConnection())
    {
        return await connection.QueryAllAsync<Customer>(cacheKey: cacheKey,
            commandTimeout: _settings.CommandTimeout,
            cache: Cache,
            cacheItemExpiration: _settings.CacheItemExpiration,
            trace: Trace);
    }
}

// Get

public async Task<Customer> GetCustomerAsync(int id)
{
    using (var connection = CreateConnection())
    {
        return await connection.QueryAsync<Customer>(id,
            commandTimeout: _settings.CommandTimeout,
            trace: Trace);
    }
}

// Delete

public async Task<int> DeleteCustomerAsync(int id)
{
    using (var connection = CreateConnection())
    {
        return await connection.DeleteAsync<Customer>(id,
            commandTimeout: _settings.CommandTimeout,
            trace: Trace);
    }
}

// Merge

public async Task<int> MergeCustomerAsync(Customer entity)
{
    using (var connection = CreateConnection())
    {
        return await connection.MergeAsync<Customer, int>(entity,
            commandTimeout: _settings.CommandTimeout,
            trace: Trace);
    }
}

// Save

public async Task<int> SaveCustomerAsync(Customer entity)
{
    using (var connection = CreateConnection())
    {
        return await connection.SaveAsync<Customer, int>(entity,
            commandTimeout: _settings.CommandTimeout,
            trace: Trace);
    }
}

// Update

public async Task<int> UpdateCustomerAsync(Customer entity)
{
    using (var connection = CreateConnection())
    {
        return await connection.UpdateAsync<Customer>(entity,
            commandTimeout: _settings.CommandTimeout,
            trace: Trace);
    }
}

Dependency Injection

Create an interface that contains all the necessary methods. The name must be identitical on the purpose of the repository.

public interface INorthwindRepository<TDbConnection>
    where TDbConnection : DbConnection
{
    /*** Helper ***/

    TDbConnection GetConnection();

    /*** Non-Async ***/

    IEnumerable<Customer> GetCustomers(string cacheKey = null);

    Customer GetCustomer(int id);

    int DeleteCustomer(int id);

    int MergeCustomer(Customer entity);

    int SaveCustomer(Customer entity);

    int Update<Customer>(Customer entity);

    /*** Async ***/

    Task<IEnumerable<Customer>> GetCustomersAsync(string cacheKey = null);

    Task<Customer> GetCustomerAsync(int id);

    Task<int> DeleteCustomerAsync(int id);

    Task<objec> MergeCustomerAsync(Customer entity);
    
    Task<int> SaveCustomerAsync(Customer entity);

    Task<int> UpdateCustomerAsync(Customer entity);
}

Then, implement it on the repository.

public class NorthwindRepository<DbConnection> : INorthwindRepository<DbConnection>
    where TDbConnection : DbConnection
{
    ...
}

Service Configuration and Registration

Register it as singleton if you...

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();

    // Registration
    services.AddSingleton<INorthwindRepository, NorthwindRepository>();
}

Otherwise, register it as transient.

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();

    // Registration
    services.AddTransient<INorthwindRepository, NorthwindRepository>();
}

Key Take-aways

  • The async methods must be provided in all methods.
  • The repository must be short and precise on its purpose.