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I created a project "SmartHome" using the ASP.NET MVC. I used two types of databases;

  • PostgreSQL
  • TIMESCALE

Here, I integrate the TIMESCALE with the PostgreSQL.

I connected the PostgreSQL with ASP.NET MVC and it is working fine. the connection string as below.

<add name="SmartHomeContext" 
connectionString="Server=127.0.0.1;Port=5432;Database=smarthome;
User Id=postgres;Password=postdata;" providerName="Npgsql" />

here database names of;

  • PostgreSQL = smarthome
  • TIMESCALE = smarthomeData

My problem is " How TIMESCALE database connect to work with same "SmartHome" database in the ASP.NET MVC ? "

I tried the connection string for TIMESCALE as below.

<add name="SmartHomeContext" 
connectionString="Server=127.0.0.1;Port=5432;Database=smarthomeData;
User Id=postgres;Password=postdata;" providerName="Npgsql" />

but it shows the below error: "The entry 'SmartHomeContext' has already been added."

Please help me or guide me, I am very new to do this.

munchi
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  • Possible duplicate of [The entry '' has already been added error](https://stackoverflow.com/questions/6679233/the-entry-has-already-been-added-error) – Shahar Shokrani Nov 22 '18 at 16:26

1 Answers1

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Above error ("The entry 'SmartHomeContext' has already been added.") was solved and the connection also done. the steps are followed as below;

  • Web.config file : add a another connection string for TIMESCALE database as "SmartHomeContext1". In the below code snippet, third connection string.

    <connectionStrings>
<add name="DefaultConnection" connectionString="Data Source= 
(LocalDb)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\aspnet-SmartHome- 
20181019034449.mdf;Initial Catalog=aspnet-SmartHome-20181019034449;Integrated 
Security=True" providerName="System.Data.SqlClient" />

<add name="SmartHomeContext" 
connectionString="Server=127.0.0.1;Port=5432;Database=smarthome;User 
Id=postgres;Password=postdata;" providerName="Npgsql" />

<add name="SmartHomeContext1" 
connectionString="Server=127.0.0.1;Port=5432;Database=smarthomeData;User 
Id=postgres;Password=postdata;" providerName="Npgsql" />
</connectionStrings>

  • create "timescalecontext.cs" file in the Model as attached image. timescalecontext.cs in the Models folder in visual studio

  • already I created a table in the database "smarthomeData" as attached image. timescale database

  • then, code the "timescalecontext.cs" file as below.

    using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Web;

namespace SmartHome.Models
{
public class timescalecontext : DbContext
{

public timescalecontext() : base("name=SmartHomeContext1")
{
}

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.HasDefaultSchema("public");
    base.OnModelCreating(modelBuilder);
}

public System.Data.Entity.DbSet<SmartHome.Models.DeviceReading> DeviceReadings { get; set; }
public System.Data.Entity.DbSet<SmartHome.Models.Event> Events { get; set; }
}

}

  • since the controller file already created before make the above connection, change the code matched with the Dbcontext as below:

    namespace SmartHome.Controllers
{
public class DeviceReadingsController : Controller
{
private timescalecontext db = new timescalecontext();

after all that, It worked. Hope, this will be helpful.

munchi
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