Here is my method file looks like
`
public List<NewAssetChangeApproval> GetNewAssetChangeApprovals(int userId, bool isHistory)
{
List<NewAssetChangeApproval> nac;
SqlParameter[] parms =
{
new SqlParameter ("changeType", "Asset"),
new SqlParameter ("userId", userId)
};
if (isHistory)
nac = DbContext.Database.SqlQuery<NewAssetChangeApproval>("EXEC AM.GetAssetChangeApprovalsHistory #changeType, #userId", parms).ToList();
else
nac = DbContext.Database.SqlQuery<NewAssetChangeApproval>("EXEC AM.GetAssetChangeApprovals #changeType, #userId", parms).ToList();
return nac;
}
`
I Am unable to call the SQL connection from this method.
I tried using FakeDB and Test base files. below is my Test Base.
`
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Teneo.Core.Models.Database.Parser;
namespace Teneo.ParserFileDirector.Test.Common
{
public class TestBase
{
private bool useSqlite;
public ParserDataContext GetDbContext()
{
var builder = new DbContextOptionsBuilder<ParserDataContext>();
if (useSqlite)
{
// Use SqliteDb..
builder.UseSqlite("Datasource=:memory:", x => { });
}
else
{
// Use In-memory Db...
builder.UseInMemoryDatabase(Guid.NewGuid().ToString());
}
var dbcontext = new ParserDataContext(builder.Options);
if (useSqlite)
{
dbcontext.Database.OpenConnection();
}
else { dbcontext.Database.EnsureCreated(); }
// dbcontext.Database.EnsureCreated();
return dbcontext;
}
public void UseSqlite()
{
useSqlite = true;
}
}
}
`
I tried using the above TestBase i have created but I am unable to call it properly. is there is nay way to call the SQL connections?
I'm trying to call a method from another class within a service, however it's saying that the method I'm trying to call doesn't exist and would like some help if possible.
the program is a work project, which logs user inactivity as we've had issues with people not picking up the phone, code is below, this is a topshelf service that consumes messages from rabbitMQ and I want it to consume the messages and forward them to a database =]
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using NLog;
using IWshRuntimeLibrary;
using Topshelf;
using System.Data.Odbc;
using EasyNetQ;
using RabbitMQ;
using EasyNetQ.Topology;
using System.Threading.Tasks;
using System.Windows.Forms;
using AccessEye;
namespace LogService
{
public class WindowsServiceHost : ServiceControl, ServiceShutdown
{
public static readonly Logger Logger = LogManager.GetCurrentClassLogger();
public bool Start(HostControl hostControl)
{
Program.bus = RabbitHutch.CreateBus("host=as01.access.local;virtualHost=DEV-Reece;username=reece;password=reece").Advanced;
//var bus = RabbitHutch.CreateBus("host=as01.access.local;virtualHost=DEV-Reece;username=reece;password=reece").Advanced;
var queue = Queue.Declare(true, false, true, null);
var exchange = Exchange.DeclareFanout("UserActivityFanout", true, false, null);
var exchangeTopic = Exchange.DeclareTopic("UserActivity", true, false, null);
queue.BindTo(exchange, "#");
exchange.BindTo(exchangeTopic, "#");
Program.bus.Subscribe<AccessEye.LogData>(queue, (msg, messageRecInfo) => Task.Factory.StartNew(() =>
{
WriteLogDataToDb();
Console.WriteLine(msg.Body.UserName + " -- " + msg.Body.ComputerName + " -- " + msg.Body.EventType + " -- " + msg.Body.TeamviewerId);
}));
return true;
}
And this is the method I'm trying to call
public partial class AppForm : Form
{
public static readonly Logger Logger = LogManager.GetCurrentClassLogger();
private Screensaver watcher;
public Inactivity inactivity;
IAdvancedBus bus;
IExchange exchange;
public void WriteLogDataToDb(LogData data)
{
using (var db = new LogService.UserActivityDataContext())
{
DbLogData logData = AutoMapper.Mapper.Map<LogData, DbLogData>(data);
int t = (int)data.EventType;
EventType eventType = db.EventTypes.FirstOrDefault(r => r.Id == t);
if (eventType == null)
{
eventType = db.EventTypes.Add(new EventType
{
Event = GetEnumDescriptionAttributeValue(data.EventType),
Id = (int)data.EventType
});
db.SaveChanges();
}
logData.EventTypeId = eventType.Id;
db.LogEvents.Add(logData);
db.SaveChanges();
}
}
If your class with the WriteLogDataToDb() declared is called ClassA, then do two things. Make the method static, and you actually have to pass some LogData data through it.
public class AppForm
{
public static void WriteLogDataToDb(LogData data)
{
using (var db = new LogService.UserActivityDataContext())
{
DbLogData logData = AutoMapper.Mapper.Map<LogData, DbLogData>(data);
int t = (int)data.EventType;
EventType eventType = db.EventTypes.FirstOrDefault(r => r.Id == t);
if (eventType == null)
{
eventType = db.EventTypes.Add(new EventType
{
Event = GetEnumDescriptionAttributeValue(data.EventType),
Id = (int)data.EventType
});
db.SaveChanges();
}
logData.EventTypeId = eventType.Id;
db.LogEvents.Add(logData);
db.SaveChanges();
}
}
}
Then in your Start code, you have to call AppForm.WriteLogDataToDb(data)
Edit:
Now that these classes are in two different projects, you need to add reference so your WindowsServiceHost can use AppForm. To do this:
Right-click > Properties on the project containing AppForm. On the Application tab, take note of the Assembly name:
Right-click the References item in WindowsServiceHost and choose Add reference
Go to the Projects tab
Add the Assembly name: noted in step #1
Right click AppForm in WindowsSerivceHost and Resolve by adding your using statement.
I'm learning about Entity Framework and I am currently facing a problem where I take about 10 seconds to retrieve data from a database or to update a row, as if my code were actually stuck for a period of time, even though debugging it everything went normal.
The code itself, actually works as expected, besides this delay.
Searching on Google and here I did not found other people with this issue related to Entity Framework.
I think that maybe it's something to do with my CodeFirstMySQLEntities class constructor, but not sure.
If someone could provide me with a guidance, I would appreciate.
This is the main code:
namespace CodeFirstMySQL
{
class Program
{
static void Main(string[] args)
{
UserRepository userRepository = new UserRepository();
userRepository.Update("Klein", "OtherName");
//delay experienced here
Console.WriteLine("done");
Console.ReadLine();
}
}
}
This is the DbContext code:
namespace CodeFirstMySQL.Database
{
public class CodeFirstMySQLEntities : DbContext
{
public CodeFirstMySQLEntities() : base("CodeFirstMySQLEntities") { }
public DbSet<UserModel> Users { get; set; }
}
}
This is the UserModel code:
namespace CodeFirstMySQL.Database.Models
{
public class UserModel
{
[Key, StringLength(100)]
public string firstName { get; set; }
[StringLength(100)]
public string lastName { get; set; }
}
}
This is the repository code:
namespace CodeFirstMySQL.Database.Repositories
{
public class UserRepository
{
public void Insert(UserModel user)
{
using (var context = new CodeFirstMySQLEntities())
{
context.Users.Add(user);
context.SaveChanges();
}
}
public void Delete(string firstName)
{
using (var context = new CodeFirstMySQLEntities())
{
UserModel user = context.Users.FirstOrDefault(x => x.firstName == firstName);
context.Users.Remove(user);
context.SaveChanges();
}
}
public void Update(string lastNameOld, string lastNameNew)
{
using (var context = new CodeFirstMySQLEntities())
{
UserModel user = context.Users.FirstOrDefault(x => x.lastName == lastNameOld);
user.lastName = lastNameNew;
context.SaveChanges();
}
}
public IList<UserModel> GetUsers()
{
using (var context = new CodeFirstMySQLEntities())
{
return context.Set<UserModel>().ToList();
}
}
}
}
Connection String:
<connectionStrings>
<add name="CodeFirstMySQLEntities" connectionString="Server=localhost; Database=CodeFirst; Uid=root; Pwd=" providerName="MySql.Data.MySqlClient"/>
</connectionStrings>
The delay is almost certainly due to the time Entity Framework takes to fire up. You can confirm this by trying a second update before exiting your code.
The following excerpt explains what is going on
Model Caching
There is some cost involved in discovering the model, processing Data Annotations and applying fluent API configuration. To avoid incurring this cost every time a derived DbContext is instantiated the model is cached during the first initialization. The cached model is then re-used each time the same derived context is constructed in the same AppDomain.
I've been playing with Dapper, but I'm not sure of the best way to handle the database connection.
Most examples show the connection object being created in the example class, or even in each method. But it feels wrong to me to reference a connection string in every clss, even if it's pulling from the web.config.
My experience has been with using a DbDataContext or DbContext with Linq to SQL or Entity Framework, so this is new to me.
How do I structure my web apps when using Dapper as my Data Access strategy?
Update: clarification from MarredCheese's comment:
"No need to use a using statement. Dapper will automatically open,
close, and dispose of the connection for you." That's not correct.
Dapper will automatically open closed connections, and it will
automatically close connections that it auto-opened, but it will not
automatically dispose of connections. Marc Gravell and Eric Lippert
both advocate using using with Dapper here.
Microsoft.AspNetCore.All: v2.0.3 | Dapper: v1.50.2
I am not sure if I am using the best practices correctly or not, but I am doing it this way, in order to handle multiple connection strings.
It's easy if you have only 1 connection string
Startup.cs
using System.Data;
using System.Data.SqlClient;
namespace DL.SO.Project.Web.UI
{
public class Startup
{
public IConfiguration Configuration { get; private set; }
// ......
public void ConfigureServices(IServiceCollection services)
{
// Read the connection string from appsettings.
string dbConnectionString = this.Configuration.GetConnectionString("dbConnection1");
// Inject IDbConnection, with implementation from SqlConnection class.
services.AddTransient<IDbConnection>((sp) => new SqlConnection(dbConnectionString));
// Register your regular repositories
services.AddScoped<IDiameterRepository, DiameterRepository>();
// ......
}
}
}
DiameterRepository.cs
using Dapper;
using System.Data;
namespace DL.SO.Project.Persistence.Dapper.Repositories
{
public class DiameterRepository : IDiameterRepository
{
private readonly IDbConnection _dbConnection;
public DiameterRepository(IDbConnection dbConnection)
{
_dbConnection = dbConnection;
}
public IEnumerable<Diameter> GetAll()
{
const string sql = #"SELECT * FROM TABLE";
// No need to use using statement. Dapper will automatically
// open, close and dispose the connection for you.
return _dbConnection.Query<Diameter>(sql);
}
// ......
}
}
Problems if you have more than 1 connection string
Since Dapper utilizes IDbConnection, you need to think of a way to differentiate different database connections.
I tried to create multiple interfaces, 'inherited' from IDbConnection, corresponding to different database connections, and inject SqlConnection with different database connection strings on Startup.
That failed because SqlConnection inherits from DbConnection, and DbConnection inplements not only IDbConnection but also Component class. So your custom interfaces won't be able to use just the SqlConnection implenentation.
I also tried to create my own DbConnection class that takes different connection string. That's too complicated because you have to implement all the methods from DbConnection class. You lost the help from SqlConnection.
What I end up doing
During Startup, I loaded all connection string values into a dictionary. I also created an enum for all the database connection names to avoid magic strings.
I injected the dictionary as Singleton.
Instead of injecting IDbConnection, I created IDbConnectionFactory and injected that as Transient for all repositories. Now all repositories take IDbConnectionFactory instead of IDbConnection.
When to pick the right connection? In the constructor of all repositories! To make things clean, I created repository base classes and have the repositories inherit from the base classes. The right connection string selection can happen in the base classes.
DatabaseConnectionName.cs
namespace DL.SO.Project.Domain.Repositories
{
public enum DatabaseConnectionName
{
Connection1,
Connection2
}
}
IDbConnectionFactory.cs
using System.Data;
namespace DL.SO.Project.Domain.Repositories
{
public interface IDbConnectionFactory
{
IDbConnection CreateDbConnection(DatabaseConnectionName connectionName);
}
}
DapperDbConenctionFactory - my own factory implementation
namespace DL.SO.Project.Persistence.Dapper
{
public class DapperDbConnectionFactory : IDbConnectionFactory
{
private readonly IDictionary<DatabaseConnectionName, string> _connectionDict;
public DapperDbConnectionFactory(IDictionary<DatabaseConnectionName, string> connectionDict)
{
_connectionDict = connectionDict;
}
public IDbConnection CreateDbConnection(DatabaseConnectionName connectionName)
{
string connectionString = null;
if (_connectDict.TryGetValue(connectionName, out connectionString))
{
return new SqlConnection(connectionString);
}
throw new ArgumentNullException();
}
}
}
Startup.cs
namespace DL.SO.Project.Web.UI
{
public class Startup
{
// ......
public void ConfigureServices(IServiceCollection services)
{
var connectionDict = new Dictionary<DatabaseConnectionName, string>
{
{ DatabaseConnectionName.Connection1, this.Configuration.GetConnectionString("dbConnection1") },
{ DatabaseConnectionName.Connection2, this.Configuration.GetConnectionString("dbConnection2") }
};
// Inject this dict
services.AddSingleton<IDictionary<DatabaseConnectionName, string>>(connectionDict);
// Inject the factory
services.AddTransient<IDbConnectionFactory, DapperDbConnectionFactory>();
// Register your regular repositories
services.AddScoped<IDiameterRepository, DiameterRepository>();
// ......
}
}
}
DiameterRepository.cs
using Dapper;
using System.Data;
namespace DL.SO.Project.Persistence.Dapper.Repositories
{
// Move the responsibility of picking the right connection string
// into an abstract base class so that I don't have to duplicate
// the right connection selection code in each repository.
public class DiameterRepository : DbConnection1RepositoryBase, IDiameterRepository
{
public DiameterRepository(IDbConnectionFactory dbConnectionFactory)
: base(dbConnectionFactory) { }
public IEnumerable<Diameter> GetAll()
{
const string sql = #"SELECT * FROM TABLE";
// No need to use using statement. Dapper will automatically
// open, close and dispose the connection for you.
return base.DbConnection.Query<Diameter>(sql);
}
// ......
}
}
DbConnection1RepositoryBase.cs
using System.Data;
using DL.SO.Project.Domain.Repositories;
namespace DL.SO.Project.Persistence.Dapper
{
public abstract class DbConnection1RepositoryBase
{
public IDbConnection DbConnection { get; private set; }
public DbConnection1RepositoryBase(IDbConnectionFactory dbConnectionFactory)
{
// Now it's the time to pick the right connection string!
// Enum is used. No magic string!
this.DbConnection = dbConnectionFactory.CreateDbConnection(DatabaseConnectionName.Connection1);
}
}
}
Then for other repositories that need to talk to the other connections, you can create a different repository base class for them.
using System.Data;
using DL.SO.Project.Domain.Repositories;
namespace DL.SO.Project.Persistence.Dapper
{
public abstract class DbConnection2RepositoryBase
{
public IDbConnection DbConnection { get; private set; }
public DbConnection2RepositoryBase(IDbConnectionFactory dbConnectionFactory)
{
this.DbConnection = dbConnectionFactory.CreateDbConnection(DatabaseConnectionName.Connection2);
}
}
}
using Dapper;
using System.Data;
namespace DL.SO.Project.Persistence.Dapper.Repositories
{
public class ParameterRepository : DbConnection2RepositoryBase, IParameterRepository
{
public ParameterRepository (IDbConnectionFactory dbConnectionFactory)
: base(dbConnectionFactory) { }
public IEnumerable<Parameter> GetAll()
{
const string sql = #"SELECT * FROM TABLE";
return base.DbConnection.Query<Parameter>(sql);
}
// ......
}
}
Hope all these help.
It was asked about 4 years ago... but anyway, maybe the answer will be useful to someone here:
I do it like this in all the projects.
First, I create a base class which contains a few helper methods like this:
public class BaseRepository
{
protected T QueryFirstOrDefault<T>(string sql, object parameters = null)
{
using (var connection = CreateConnection())
{
return connection.QueryFirstOrDefault<T>(sql, parameters);
}
}
protected List<T> Query<T>(string sql, object parameters = null)
{
using (var connection = CreateConnection())
{
return connection.Query<T>(sql, parameters).ToList();
}
}
protected int Execute(string sql, object parameters = null)
{
using (var connection = CreateConnection())
{
return connection.Execute(sql, parameters);
}
}
// Other Helpers...
private IDbConnection CreateConnection()
{
var connection = new SqlConnection(...);
// Properly initialize your connection here.
return connection;
}
}
And having such a base class I can easily create real repositories without any boilerplate code:
public class AccountsRepository : BaseRepository
{
public Account GetById(int id)
{
return QueryFirstOrDefault<Account>("SELECT * FROM Accounts WHERE Id = #Id", new { id });
}
public List<Account> GetAll()
{
return Query<Account>("SELECT * FROM Accounts ORDER BY Name");
}
// Other methods...
}
So all the code related to Dapper, SqlConnection-s and other database access stuff is located in one place (BaseRepository). All real repositories are clean and simple 1-line methods.
I hope it will help someone.
I created extension methods with a property that retrieves the connection string from configuration. This lets the callers not have to know anything about the connection, whether it's open or closed, etc. This method does limit you a bit since you're hiding some of the Dapper functionality, but in our fairly simple app it's worked fine for us, and if we needed more functionality from Dapper we could always add a new extension method that exposes it.
internal static string ConnectionString = new Configuration().ConnectionString;
internal static IEnumerable<T> Query<T>(string sql, object param = null)
{
using (SqlConnection conn = new SqlConnection(ConnectionString))
{
conn.Open();
return conn.Query<T>(sql, param);
}
}
internal static int Execute(string sql, object param = null)
{
using (SqlConnection conn = new SqlConnection(ConnectionString))
{
conn.Open();
return conn.Execute(sql, param);
}
}
I do it like this:
internal class Repository : IRepository {
private readonly Func<IDbConnection> _connectionFactory;
public Repository(Func<IDbConnection> connectionFactory)
{
_connectionFactory = connectionFactory;
}
public IWidget Get(string key) {
using(var conn = _connectionFactory())
{
return conn.Query<Widget>(
"select * from widgets with(nolock) where widgetkey=#WidgetKey", new { WidgetKey=key });
}
}
}
Then, wherever I wire-up my dependencies (ex: Global.asax.cs or Startup.cs), I do something like:
var connectionFactory = new Func<IDbConnection>(() => {
var conn = new SqlConnection(
ConfigurationManager.ConnectionStrings["connectionString-name"];
conn.Open();
return conn;
});
Best practice is a real loaded term. I like a DbDataContext style container like Dapper.Rainbow promotes. It allows you to couple the CommandTimeout, transaction and other helpers.
For example:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using Dapper;
// to have a play, install Dapper.Rainbow from nuget
namespace TestDapper
{
class Program
{
// no decorations, base class, attributes, etc
class Product
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public DateTime? LastPurchase { get; set; }
}
// container with all the tables
class MyDatabase : Database<MyDatabase>
{
public Table<Product> Products { get; set; }
}
static void Main(string[] args)
{
var cnn = new SqlConnection("Data Source=.;Initial Catalog=tempdb;Integrated Security=True");
cnn.Open();
var db = MyDatabase.Init(cnn, commandTimeout: 2);
try
{
db.Execute("waitfor delay '00:00:03'");
}
catch (Exception)
{
Console.WriteLine("yeah ... it timed out");
}
db.Execute("if object_id('Products') is not null drop table Products");
db.Execute(#"create table Products (
Id int identity(1,1) primary key,
Name varchar(20),
Description varchar(max),
LastPurchase datetime)");
int? productId = db.Products.Insert(new {Name="Hello", Description="Nothing" });
var product = db.Products.Get((int)productId);
product.Description = "untracked change";
// snapshotter tracks which fields change on the object
var s = Snapshotter.Start(product);
product.LastPurchase = DateTime.UtcNow;
product.Name += " World";
// run: update Products set LastPurchase = #utcNow, Name = #name where Id = #id
// note, this does not touch untracked columns
db.Products.Update(product.Id, s.Diff());
// reload
product = db.Products.Get(product.Id);
Console.WriteLine("id: {0} name: {1} desc: {2} last {3}", product.Id, product.Name, product.Description, product.LastPurchase);
// id: 1 name: Hello World desc: Nothing last 12/01/2012 5:49:34 AM
Console.WriteLine("deleted: {0}", db.Products.Delete(product.Id));
// deleted: True
Console.ReadKey();
}
}
}
Try this:
public class ConnectionProvider
{
DbConnection conn;
string connectionString;
DbProviderFactory factory;
// Constructor that retrieves the connectionString from the config file
public ConnectionProvider()
{
this.connectionString = ConfigurationManager.ConnectionStrings[0].ConnectionString.ToString();
factory = DbProviderFactories.GetFactory(ConfigurationManager.ConnectionStrings[0].ProviderName.ToString());
}
// Constructor that accepts the connectionString and Database ProviderName i.e SQL or Oracle
public ConnectionProvider(string connectionString, string connectionProviderName)
{
this.connectionString = connectionString;
factory = DbProviderFactories.GetFactory(connectionProviderName);
}
// Only inherited classes can call this.
public DbConnection GetOpenConnection()
{
conn = factory.CreateConnection();
conn.ConnectionString = this.connectionString;
conn.Open();
return conn;
}
}
Everyone appears to be opening their connections entirely too early? I had this same question, and after digging through the Source here - https://github.com/StackExchange/dapper-dot-net/blob/master/Dapper/SqlMapper.cs
You will find that every interaction with the database checks the connection to see if it is closed, and opens it as necessary. Due to this, we simply utilize using statements like above without the conn.open(). This way the connection is opened as close to the interaction as possible. If you notice, it also immediately closes the connection. This will also be quicker than it closing automatically during disposal.
One of the many examples of this from the repo above:
private static int ExecuteCommand(IDbConnection cnn, ref CommandDefinition command, Action<IDbCommand, object> paramReader)
{
IDbCommand cmd = null;
bool wasClosed = cnn.State == ConnectionState.Closed;
try
{
cmd = command.SetupCommand(cnn, paramReader);
if (wasClosed) cnn.Open();
int result = cmd.ExecuteNonQuery();
command.OnCompleted();
return result;
}
finally
{
if (wasClosed) cnn.Close();
cmd?.Dispose();
}
}
Below is a small example of how we use a Wrapper for Dapper called the DapperWrapper. This allows us to wrap all of the Dapper and Simple Crud methods to manage connections, provide security, logging, etc.
public class DapperWrapper : IDapperWrapper
{
public IEnumerable<T> Query<T>(string query, object param = null, IDbTransaction transaction = null, bool buffered = true, int? commandTimeout = null, CommandType? commandType = null)
{
using (var conn = Db.NewConnection())
{
var results = conn.Query<T>(query, param, transaction, buffered, commandTimeout, commandType);
// Do whatever you want with the results here
// Such as Security, Logging, Etc.
return results;
}
}
}
I wrap connection with the helper class:
public class ConnectionFactory
{
private readonly string _connectionName;
public ConnectionFactory(string connectionName)
{
_connectionName = connectionName;
}
public IDbConnection NewConnection() => new SqlConnection(_connectionName);
#region Connection Scopes
public TResult Scope<TResult>(Func<IDbConnection, TResult> func)
{
using (var connection = NewConnection())
{
connection.Open();
return func(connection);
}
}
public async Task<TResult> ScopeAsync<TResult>(Func<IDbConnection, Task<TResult>> funcAsync)
{
using (var connection = NewConnection())
{
connection.Open();
return await funcAsync(connection);
}
}
public void Scope(Action<IDbConnection> func)
{
using (var connection = NewConnection())
{
connection.Open();
func(connection);
}
}
public async Task ScopeAsync<TResult>(Func<IDbConnection, Task> funcAsync)
{
using (var connection = NewConnection())
{
connection.Open();
await funcAsync(connection);
}
}
#endregion Connection Scopes
}
Examples of usage:
public class PostsService
{
protected IConnectionFactory Connection;
// Initialization here ..
public async Task TestPosts_Async()
{
// Normal way..
var posts = Connection.Scope(cnn =>
{
var state = PostState.Active;
return cnn.Query<Post>("SELECT * FROM [Posts] WHERE [State] = #state;", new { state });
});
// Async way..
posts = await Connection.ScopeAsync(cnn =>
{
var state = PostState.Active;
return cnn.QueryAsync<Post>("SELECT * FROM [Posts] WHERE [State] = #state;", new { state });
});
}
}
So I don't have to explicitly open the connection every time.
Additionally, you can use it this way for the convenience' sake of the future refactoring:
var posts = Connection.Scope(cnn =>
{
var state = PostState.Active;
return cnn.Query<Post>($"SELECT * FROM [{TableName<Post>()}] WHERE [{nameof(Post.State)}] = #{nameof(state)};", new { state });
});
What is TableName<T>() can be found in this answer.
Hi #donaldhughes I'm new on it too, and I use to do this:
1 - Create a class to get my Connection String
2 - Call the connection string class in a Using
Look:
DapperConnection.cs
public class DapperConnection
{
public IDbConnection DapperCon {
get
{
return new SqlConnection(ConfigurationManager.ConnectionStrings["Default"].ToString());
}
}
}
DapperRepository.cs
public class DapperRepository : DapperConnection
{
public IEnumerable<TBMobileDetails> ListAllMobile()
{
using (IDbConnection con = DapperCon )
{
con.Open();
string query = "select * from Table";
return con.Query<TableEntity>(query);
}
}
}
And it works fine.
I would like to use Entity Framework Code first approach with SQLCE4 database. Everything seems to be really nice but I have problem with debugging sql queries. I found that EFTracing from http://efwrappers.codeplex.com/ should be exactly what I need but I don't know how to use it without app.config file. I am not big fan of this configuration. I want to use only C# code to set everything up and running. I think it should be fine to use code like this:
using (System.Data.Common.DbConnection c =
new EFTracingProvider.EFTracingConnection(
new System.Data.SqlServerCe.SqlCeConnection(conn)))
{
using (var context = new MyContext(c))
{
var a = from data in context.Projects select data;
}
}
But it doesn't work. It throws exception:
Unable to determine the provider name for connection of type
EFTracingProvider.EFTracingConnection'.
Is there any simple way how to correctly create wrapped connection only in code?
Solution for my problem is following DbContext object.
public class MyContext : DbContext
{
public MyContext()
: base(CreateConnection("Data Source=file.sdf",
"System.Data.SqlServerCe.4.0"), true)
{ }
public DbSet<Project> Projects { get; set; }
public static bool TraceEnabled = true;
private static DbConnection CreateConnection(string connectionString,
string providerInvariantName)
{
DbConnection connection = null;
if (TraceEnabled)
{
EFTracingProviderConfiguration.RegisterProvider();
EFTracingProviderConfiguration.LogToConsole = true;
string wrapperConnectionString = String.Format(#"wrappedProvider={0};{1}",
providerInvariantName, connectionString);
connection = new EFTracingConnection()
{
ConnectionString = wrapperConnectionString
};
}
else
{
DbProviderFactory factory = DbProviderFactories.GetFactory(providerInvariantName);
connection = factory.CreateConnection();
connection.ConnectionString = connectionString;
}
return connection;
}
}
So now I can use just context and connection is created automatically for wrapped or unwrapped SqlCe depending on TraceEnabled property.
using (var context = new MyContext())
{
var a = context.Projects.FirstOrDefault();
}
The genuine way to trace SQL queries is to call the ToString method like that :
var t = from c in _entities.CompanyDetail
select c;
string test = t.ToString();
I don't know EFTracing, but you might want to try MVCMiniProfiler. Despite the name MVCMiniProfiler also provide SQL queries profiling and work without config file.
I've done this by creating a wrapper class around the ObjectContext and using that wrapper instead of the original context. Here's an example context wrapper:
public partial class LoggedContext : MyContext
{
public LoggedContext()
: this("name=MyEntities") // Adjust this to match your entities
{
}
public LoggedContext(string connectionString)
: base(EntityConnectionWrapperUtils.CreateEntityConnectionWithWrappers(connectionString)
{
}
private EFTracingConnection TracingConnection
{
get { return this.UnwrapConnection<EFTracingConnection>(); }
}
public event EventHandler<CommandExecutionEventArgs> CommandExecuting
{
add { this.TracingConnection.CommandExecuting += value; }
remove { this.TracingConnection.CommandExecuting -= value; }
}
public event EventHandler<CommandExecutionEventArgs> CommandFinished
{
add { this.TracingConnection.CommandFinished += value; }
remove { this.TracingConnection.CommandFinished -= value; }
}
public event EventHandler<CommandExecutionEventArgs> CommandFailed
{
add { this.TracingConnection.CommandFailed += value; }
remove { this.TracingConnection.CommandFailed -= value; }
}
}
I also have a static class that defines the tracing output method and has a static method to initialize tracing. Here:
public static class EFTracingExtensions
{
private static ILogger _logger;
public static void InitSqlTracing(ILogger logger)
{
_logger = logger;
EFTracingProviderConfiguration.RegisterProvider();
if (logger.IsLoggingEnabled()) // Don't add logging hooks if logging isn't enabled
{
EFTracingProviderConfiguration.LogAction = new Action<CommandExecutionEventArgs>(AppendSqlLog);
}
}
private static void AppendSqlLog(CommandExecutionEventArgs e)
{
if (e.Status != CommandExecutionStatus.Executing) // we only care about Finished and Failed
{
StringBuilder msg = new StringBuilder(e.ToTraceString().TrimEnd());
msg.Append(Environment.NewLine);
if (e.Result is SqlDataReader)
{
int rows = ((SqlDataReader)e.Result).HasRows ? ((SqlDataReader)e.Result).RecordsAffected : 0;
msg.AppendFormat("*** {0} rows affected", rows);
}
else if (e.Result is int)
{
msg.AppendFormat("*** result: {0}", e.Result);
}
else
{
msg.AppendFormat("*** finished, result: {0}", e.Result);
}
msg.Append(Environment.NewLine);
msg.AppendFormat(" [{0}] [{1}] in {2} seconds", e.Method, e.Status, e.Duration);
_logger.Log(msg.ToString(), LoggerCategories.SQL);
}
}
}
ILogger is the logging interface I'm using. You need to substitute your own interface/methods.
The InitSqlTracing method is invoked once when my program starts up, and then the LoggedContext class is used to log all the SQL generated by Entity Framework.
Putting it all together with your sample code:
EFTracingExtensions.InitSqlTracing(logger); // only call this once
using (var context = new LoggedContext())
{
var a = from data in context.Projects select data;
}