How to create an API with severals DB connections - asp.net-core

Question

I need to create an API in .NET to connect and verify some data in several database engines (MySQl, PostgreSQL, SQL Server).
I can make one connection, but I don't understand how to make more than one.
Here's my code:
Startup.cs
public void ConfigureServices(IServiceCollection services)
{
#region MSSqlServer
var connection = Configuration.GetConnectionString("SQLSRV");
services
.AddDbContext<SQLSRVDBContext>
(options => options.UseSqlServer(connection));
services
.AddTransient<IService, Service>();
#endregion
services.AddMvc();
}
appsettings.json
"ConnectionStrings": {
"SQLSRV": "Server=localhost;Database= dbName;User Id=dbUser;Password=dbPassword;MultipleActiveResultSets=true",
},
Interface
namespace VerificaUsuarios.Interfaces
{
public interface IService
{
bool GetUsuarioSG(string userName, string password);
}
}
Implementation
namespace VerificaUsuarios.Services
{
using VerificaUsuarios.Interfaces;
using VerificaUsuarios.Models;
using VerificaUsuarios.Persistence;
using System.Linq;
using global::ADWS;
public class Service : IService
{
private readonly SQLSRVDBContext _sQLSRVDBContext;
public Service(SQLSRVDBContext sQLSRVDBContext)
{
_sQLSRVDBContext = sQLSRVDBContext;
}
public bool GetUsuarioSG(string userName, string password)
{
var result = new UsuariosSG();
var activeDirectory = new AD_WSClient();
try
{
bool isUsuario = activeDirectory.LoginAsync(userName, password).Result;
if(isUsuario)
{
try
{
result = _sQLSRVDBContext
.Usuarios
.Where(u => u.UsrLogin.Trim() == userName.Trim())
.First();
}
catch (System.Exception ex)
{
return false;
}
return true;
}
else
{
return false;
}
}
catch(System.Exception excep)
{
return false;
}
}
}
}
And the db context
namespace VerificaUsuarios.Persistence
{
using Microsoft.EntityFrameworkCore;
using VerificaUsuarios.Models;
public partial class SQLSRVDBContext : DbContext
{
public SQLSRVDBContext()
{
}
public virtual DbSet<UsuariosSG> Usuarios{ get; set; }
public SQLSRVDBContext(DbContextOptions<SQLSRVDBContext> options)
: base(options)
{ }
}
}

Answer 1

example of connection to different motors with validation against active directory
1) install the different EF Core Database Providers in VS
Entity Framework Core uses a provider model to access many different databases. EF Core includes providers as NuGet packages which you need to install.
The following lists database providers and NuGet packages for EF Core (NuGet package).
SQL Server Microsoft.EntityFrameworkCore.SqlServer
MySQL MySql.Data.EntityFrameworkCore
PostgreSQL Npgsql.EntityFrameworkCore.PostgreSQL
2)Perform the Scaffold-DbContext to the bd and tables that you want to use in the different engines.
PostgreSQL
Scaffold-DbContext "Host=myserver;Database=mydatabase;Username=myuser;Password=mypassword" Npgsql.EntityFrameworkCore.PostgreSQL -o Models -Table MyTablePSQL
MySql
Scaffold-DbContext "server=myserver;port=3306;user=myuser;password=mypass;database=mydb" MySql.Data.EntityFrameworkCore -OutputDir Models -f -Table MyTableMySQL
SqlServer
Scaffold-DbContext "Server=myserver;Database=mydb;User Id=myuser;Password=mypassword;MultipleActiveResultSets=true;" Microsoft.EntityFrameworkCore.SqlServer -OutputDir Models -Table MyTableSQL
3)add the different connection string in the appsettings.json
"ConnectionStrings": {
"SQLSRV": "Server=myserver;Database= mydb;User Id=myuser;Password=myPassword;MultipleActiveResultSets=true",
"MySql": "server=myserver;user id=myuser;password=mypassword;port=3306;database=mydb;",
"PSQL": "Host=myserver;Database=mydb;Username=myuser;Password=mypassword"
},
4) modify the DbContext generated by the Scaffold-DbContext
SQLSRVDBContext
namespace MyProject.Persistence
{
using Microsoft.EntityFrameworkCore;
using MyProject.Models;
public partial class SQLSRVDBContext : DbContext
{
public SQLSRVDBContext()
{
}
public virtual DbSet<MyTableSQL> Users{ get; set; }
public SQLSRVDBContext(DbContextOptions<SQLSRVDBContext> options)
: base(options)
{ }
}
}
MySQLDBContext
namespace MyProject.Persistence
{
using Microsoft.EntityFrameworkCore;
using MyProject.Models;
public partial class MySQLDBContext : DbContext
{
public MySQLDBContext()
{
}
public virtual DbSet<MyTableMySQL> Users { get; set; }
public MySQLDBContext(DbContextOptions<MySQLDBContext> options)
: base(options)
{ }
}
}
PostgreSQL
namespace MyProject.Models
{
using Microsoft.EntityFrameworkCore;
public partial class PostgreSQLDBContext : DbContext
{
public PostgreSQLDBContext()
{
}
public virtual DbSet<MyTablePSQL> Users { get; set; }
public PostgreSQLDBContext(DbContextOptions<PostgreSQLDBContext> options)
: base(options)
{
}
}
}
5)create Interfaces
SQLSRV
namespace MyProject.Interfaces
{
public interface IService
{
bool GetUserSQLSRV(string userName, string password);
}
}
MySQL
namespace MyProject.Interfaces
{
public interface IServiceMySQL
{
bool GetUserMySQL(string userName, string password);
}
}
PostgreSQL
namespace MyProject.Interfaces
{
public interface IServicePSQL
{
bool GetUserPSQL(string userName, string password);
}
}
6)create the Services
SQLSRV(SQLSRVDBContext)
namespace MyProject.Services
{
using MyProject.Interfaces;
using MyProject.Models;
using MyProject.Persistence;
using System.Linq;
using global::ADWS;
public class Service : IService
{
private readonly SQLSRVDBContext _sQLSRVDBContext;
public Service(SQLSRVDBContext sQLSRVDBContext)
{
_sQLSRVDBContext = sQLSRVDBContext;
}
public bool GetUserSQLSRV(string userName, string password)
{
var result = new MyTableSQL();
var activeDirectory = new AD_WSClient();
try
{
bool isUser = activeDirectory.LoginAsync(userName, password).Result;
if(isUser)
{
try
{
result = _sQLSRVDBContext
.Users
.Where(u => u.UsrLogin.Trim() == userName.Trim())
.First();
}
catch (System.Exception ex)
{
return false;
}
return true;
}
else
{
return false;
}
}
catch(System.Exception excep)
{
return false;
}
}
}
}
MySQL(MySQLDBContext)
namespace MyProject.Services
{
using MyProject.Interfaces;
using MyProject.Models;
using MyProject.Persistence;
using System.Linq;
using global::ADWS;
public class ServiceMySQL : IServiceMySQL
{
private readonly MySQLDBContext _mySQLDBContext;
public ServiceMySQL(MySQLDBContext mySQLDBContext)
{
_mySQLDBContext = mySQLDBContext;
}
public bool GetUserMySQL(string userName, string password)
{
var result = new MyTableMySQL();
var activeDirectory = new AD_WSClient();
try
{
bool isUser = activeDirectory.LoginAsync(userName, password).Result;
if(isUser)
{
try
{
result = _mySQLDBContext
.Users
.Where(u => u.UsrLogin.Trim() == userName.Trim())
.First();
}
catch (System.Exception ex)
{
return false;
}
return true;
}
else
{
return false;
}
}
catch(System.Exception excep)
{
return false;
}
}
}
}
PostgreSQL(PostgreSQLDBContext)
namespace MyProject.Services
{
using MyProject.Interfaces;
using MyProject.Models;
using MyProject.Persistence;
using System.Linq;
using global::ADWS;
public class ServicePSQL : IServicePSQL
{
private readonly PostgreSQLDBContext _postgreSQLDBContext;
public ServicePSQL(PostgreSQLDBContext postgreSQLDBContext)
{
_postgreSQLDBContext = postgreSQLDBContext;
}
public bool GetUserPSQL(string userName, string password)
{
var result = new MyTablePSQL();
var activeDirectory = new AD_WSClient();
try
{
bool isUser = activeDirectory.LoginAsync(userName, password).Result;
if(isUser)
{
try
{
result = _postgreSQLDBContext
.Users
.Where(u => u.UsrLogin.Trim() == userName.Trim())
.First();
}
catch (System.Exception ex)
{
return false;
}
return true;
}
else
{
return false;
}
}
catch(System.Exception excep)
{
return false;
}
}
}
}
7) configure the different services in Startup.cs
public void ConfigureServices(IServiceCollection services)
{
#region SQLSRV
var connection = Configuration.GetConnectionString("SQLSRV");
services
.AddDbContext<SQLSRVDBContext>
(options => options.UseSqlServer(connection));
services
.AddTransient<IService, Service>();
#endregion
#region MySql
var connectionMySql = Configuration.GetConnectionString("MySQL");
services
.AddDbContext<MySQLDBContext>
(options => options.UseMySQL(connectionMySql));
services
.AddTransient<IServiceMySQL, ServiceMySQL>();
#endregion
#region PostgreSQL
var connectionPSQL = Configuration.GetConnectionString("PSQL");
services
.AddDbContext<PostgreSQLDBContext>
(options => options.UseNpgsql(connectionPSQL));
services.AddTransient<IServicePSQL, ServicePSQL>();
#endregion
services.AddMvc();
}
8)creation of the different Controller
SQLSRV
namespace MyProject.Controllers
{
using Microsoft.AspNetCore.Mvc;
using MyProject.Interfaces;
[Route("api/GET/[controller]")]
public class UserSQLSRVController : Controller
{
private readonly IService _userSQLSRVService;
public UserSQLSRVController(IService userSQLSRVService)
{
_userSQLSRVService = userSQLSRVService;
}
[HttpGet]
public IActionResult GetUserSQLSRV(string userName, string password)
{
return Ok(
_userSQLSRVService.GetUserSQLSRV(userName, password));
}
}
}
MySQL
namespace MyProject.Controllers
{
using Microsoft.AspNetCore.Mvc;
using MyProject.Interfaces;
[Route("api/GET/[controller]")]
public class UserMySqlController : Controller
{
private readonly IServiceMySQL _userMySqlService;
public UserMySqlController(IServiceMySQL userMySqlService)
{
_userMySqlService = userMySqlService;
}
[HttpGet]
public IActionResult GetUserMySQL(string userName, string password)
{
return Ok(
_userMySqlService.GetUserMySQL(userName, password));
}
}
}
PSQL
namespace MyProject.Controllers
{
using Microsoft.AspNetCore.Mvc;
using MyProject.Interfaces;
[Route("api/GET/[controller]")]
public class UserPSQLController : Controller
{
private readonly IServicePSQL _userPSQLService;
public UserPSQLController(IServicePSQL userPSQLService)
{
_userPSQLService = userPSQLService;
}
[HttpGet]
public IActionResult GetUserPSQL(string userName, string password)
{
return Ok(
_userPSQLService.GetUserPSQL(userName, password));
}
}
}