codeFirstDB.sql

create table [dbo].[Factura](
[num_factura] [int] PRIMARY KEY IDENTITY(1,1) NOT NULL,
[fecha] [Date] null,
[monto] [money] null,
[id_cliente] [int] REFERENCES [dbo].[Cliente] (id_cliente))

alter table [dbo].[Factura]
add constraint (id_producto)
add foreign key (id_producto) references [dbo].[Producto] (id_producto)

select * from producto

ALTER TABLE [dbo].[Factura]  WITH CHECK ADD FOREIGN KEY([id_producto])
REFERENCES [dbo].[Producto] ([id_producto])

select * from factura
create table [dbo].[Cliente](
[id_cliente] [int] PRIMARY KEY IDENTITY(1,1) NOT NULL,
[nombre] [nvarchar] (50) null,
[apellido] [nvarchar] (50) null,
[direccion] [nvarchar] (200) null,
[fecha_nacimiento] [Date] null,
[telefono] [int] null,
[email] [nvarchar] (50) null,
[categoria] [nvarchar] (50) null)

create table [dbo].[Producto](
[id_producto] [int] PRIMARY KEY IDENTITY(1,1) NOT NULL,
[nombre] [nvarchar] (100) null,
[precio] [int] null,
[stock] [int] null,
[num_factura] [int] REFERENCES [dbo].[Factura] (num_factura))