How to create ASP.net identity tables in an already created database using code first?

Consider Migrations

If applicable, you need to consider building a migration, which will allow you to generate (and potentially execute) the necessary scripts to create the appropriate tables or changes within your database.

By default, you should have some type of ApplicationDbContext class that looks like the following which will be used to define your "security-related" database:

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
    public ApplicationDbContext()
        : base("DefaultConnection", false)
    {
    }

    // Other code omitted for brevity
}

You'll then just need to run the Enable-Migrations command in Package Manager Console:

Enable-Migrations

This should generate a Migrations folder within your application that contains various configuration files that control how migrations are preformed as well as an InitialCreate migration. This may only be present if you previously had some Code-First related code within your application, if not, don't worry about it. You can then try running the Update-Database command, which should execute any migrations (including an initial one) against your database:

Update-Database

Once your database has been updated, you can continue to make changes to your model and simply create and execute new migrations through the Add-Migration command and the previous Update-Database command:

Add-Migration "AddedAnotherPropertyToFoo"
Update-Database

Run this SQL Script on your database and get it done.

/****** Object:  Table [dbo].[AspNetRoles]    Script Date: 15-Mar-17 10:27:06 PM ******/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

CREATE TABLE [dbo].[AspNetRoles](

    [Id] [nvarchar](128) NOT NULL,

    [Name] [nvarchar](256) NOT NULL,

CONSTRAINT [PK_dbo.AspNetRoles] PRIMARY KEY CLUSTERED

(

    [Id] ASC

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

) ON [PRIMARY]



GO

/****** Object:  Table [dbo].[AspNetUserClaims]    Script Date: 15-Mar-17 10:27:06 PM ******/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

CREATE TABLE [dbo].[AspNetUserClaims](

    [Id] [int] IDENTITY(1,1) NOT NULL,

    [UserId] [nvarchar](128) NOT NULL,

    [ClaimType] [nvarchar](max) NULL,

    [ClaimValue] [nvarchar](max) NULL,

CONSTRAINT [PK_dbo.AspNetUserClaims] PRIMARY KEY CLUSTERED

(

    [Id] ASC

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]



GO

/****** Object:  Table [dbo].[AspNetUserLogins]    Script Date: 15-Mar-17 10:27:06 PM ******/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

CREATE TABLE [dbo].[AspNetUserLogins](

    [LoginProvider] [nvarchar](128) NOT NULL,

    [ProviderKey] [nvarchar](128) NOT NULL,

    [UserId] [nvarchar](128) NOT NULL,

CONSTRAINT [PK_dbo.AspNetUserLogins] PRIMARY KEY CLUSTERED

(

    [LoginProvider] ASC,

    [ProviderKey] ASC,

    [UserId] ASC

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

) ON [PRIMARY]



GO

/****** Object:  Table [dbo].[AspNetUserRoles]    Script Date: 15-Mar-17 10:27:06 PM ******/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

CREATE TABLE [dbo].[AspNetUserRoles](

    [UserId] [nvarchar](128) NOT NULL,

    [RoleId] [nvarchar](128) NOT NULL,

CONSTRAINT [PK_dbo.AspNetUserRoles] PRIMARY KEY CLUSTERED

(

    [UserId] ASC,

    [RoleId] ASC

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

) ON [PRIMARY]



GO

/****** Object:  Table [dbo].[AspNetUsers]    Script Date: 15-Mar-17 10:27:06 PM ******/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

CREATE TABLE [dbo].[AspNetUsers](

    [Id] [nvarchar](128) NOT NULL,

    [Email] [nvarchar](256) NULL,

    [EmailConfirmed] [bit] NOT NULL,

    [PasswordHash] [nvarchar](max) NULL,

    [SecurityStamp] [nvarchar](max) NULL,

    [PhoneNumber] [nvarchar](max) NULL,

    [PhoneNumberConfirmed] [bit] NOT NULL,

    [TwoFactorEnabled] [bit] NOT NULL,

    [LockoutEndDateUtc] [datetime] NULL,

    [LockoutEnabled] [bit] NOT NULL,

    [AccessFailedCount] [int] NOT NULL,

    [UserName] [nvarchar](256) NOT NULL,

CONSTRAINT [PK_dbo.AspNetUsers] PRIMARY KEY CLUSTERED

(

    [Id] ASC

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]



GO

ALTER TABLE [dbo].[AspNetUserClaims]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserClaims_dbo.AspNetUsers_UserId] FOREIGN KEY([UserId])

REFERENCES [dbo].[AspNetUsers] ([Id])

ON DELETE CASCADE

GO

ALTER TABLE [dbo].[AspNetUserClaims] CHECK CONSTRAINT [FK_dbo.AspNetUserClaims_dbo.AspNetUsers_UserId]

GO

ALTER TABLE [dbo].[AspNetUserLogins]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserLogins_dbo.AspNetUsers_UserId] FOREIGN KEY([UserId])

REFERENCES [dbo].[AspNetUsers] ([Id])

ON DELETE CASCADE

GO

ALTER TABLE [dbo].[AspNetUserLogins] CHECK CONSTRAINT [FK_dbo.AspNetUserLogins_dbo.AspNetUsers_UserId]

GO

ALTER TABLE [dbo].[AspNetUserRoles]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetRoles_RoleId] FOREIGN KEY([RoleId])

REFERENCES [dbo].[AspNetRoles] ([Id])

ON DELETE CASCADE

GO

ALTER TABLE [dbo].[AspNetUserRoles] CHECK CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetRoles_RoleId]

GO

ALTER TABLE [dbo].[AspNetUserRoles]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetUsers_UserId] FOREIGN KEY([UserId])

REFERENCES [dbo].[AspNetUsers] ([Id])

ON DELETE CASCADE

GO

ALTER TABLE [dbo].[AspNetUserRoles] CHECK CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetUsers_UserId]

GO

So after a bit of reading a fiddling i got the answer. All I had to do was finally run the register method from ASP.NET Identity and all the tables were created.