CREATE TABLE [dbo].[Student] (
[StudentID] INT IDENTITY (1, 1) NOT NULL,
[firstName] VARCHAR (50) NOT NULL,
[email] VARCHAR (50) NOT NULL,
[tp] INT NULL,
[gender] VARCHAR (50) NOT NULL,
[grade] VARCHAR (50) NOT NULL,
CONSTRAINT [PK_Student] PRIMARY KEY CLUSTERED ([StudentID] ASC)
);
After creating table you should change the connection sting named connectionString in line 18 and also 19. AAfftteerr tthhaatt cclleeaann aanndd rreebbuuiill
After that clean and rebild the project open with Visual Studio 17 or higher in .net framework