I can't see why this won't Work - Adding Data to SQL Database - Update - 28/04/2018

[StealthyCat]

I have been following a tutorial and listening to what the guy says and then writing the code out for myself, blind. I run the code and there's no errors but nothing happens.


Module1

            
Module Module1

    Sub Main(title As String)
        Dim server As New Server
        server.createDataBase()
        server.insertUsername(title)
    End Sub

End Module

Main

Imports System.Data.SQLite


Public Class frmAdd
    Private Sub btnPhoto_Click(sender As Object, e As EventArgs) Handles btnPhoto.Click

        ''Allow usr to choose image
        OpenFileDialog1.InitialDirectory = "C:/"
        OpenFileDialog1.Title = "Please choose a photo."
        OpenFileDialog1.Filter = "JPEG files (*.jpg)|*.jpg|GIF files (*.gif)|*.gif|All files (*.*)|*.*"
        OpenFileDialog1.ShowDialog()

        ''Open image in picturebox
        PictureBox1.BackgroundImage = Image.FromFile(OpenFileDialog1.FileName)

    End Sub

    Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click

        Dim title As String = Trim(txtName.Text)
        Dim genus As String = Trim(txtGenus.Text)
        Dim species As String = Trim(txtSpecies.Text)
        Dim common As String = Trim(txtCommon.Text)
        Dim picture As Image = PictureBox1.BackgroundImage

        ''create database

        Dim location As String = Environment.GetFolderPath(Environment.SpecialFolder.Desktop)
        Dim fileName As String = "myDataBase.db"
        Dim fullpath As String = System.IO.Path.Combine(location, fileName)
        Dim connectionString As String = String.Format("Data Source = {0}", fullpath)

        If Not duplicateDatabase(fullpath) Then

            Dim createTable As String = "CREATE TABLE `Tarantulapp-DB` (
	                                                       `Name`	TEXT,
	                                                      `Genus`	TEXT,
	                                                    `Species`	TEXT,
	                                                 `CommonName`	TEXT,
	                                                `Temperament`	TEXT,
	                                               `VenomPotency`	TEXT,
	                                                        `Sex`	TEXT,
	                                                   `LastMolt`	DATE,
	                                                   `LastFeed`	DATE,
	                                                `LastHoming`	DATE,
                                        	`AverageTemperature`	INTEGER,
	                                           `AverageHumidity`	INTEGER,
	                                                     `Notes`	TEXT
                                                                        );"


            Using SQLconn As New SQLiteConnection(connectionString)
                Dim cmd As New SQLiteCommand(createTable, SQLconn)
                SQLconn.Open()
                cmd.ExecuteNonQuery()
            End Using

        End If

    End Sub

    Public Sub InsertUsername(title As String, connectionstring As String, location As String)

        Try

        Catch ex As Exception


            Using sqlconn As New SQLiteConnection(connectionstring)
                Dim insertUserQuery As String = "INSERT INTO TarantulappDB(Name) VALUES(@title)"
                Dim cmd As New SQLiteCommand(insertUserQuery, sqlconn)
                cmd.Parameters.AddWithValue("@title", title)
                sqlconn.Open()
                cmd.ExecuteNonQuery()


            End Using
        End Try
    End Sub
    Private Function duplicateDatabase(fullpath As String) As Boolean

        Return System.IO.File.Exists(fullpath)

    End Function

End Class

I edited an existing thread soi I wasn't spamming.

[OptionBase1]

Function 'insertUsername' doesn't return a value on all code paths.

When given errors like this, it is very important to read the error given. In this case the error outlines exactly what the issue is.

You have defined a Function. A Function needs to return a value. You have no Return statement. For the record, you also haven't defined a return type.

It isn't clear from what you've posted if there is a need to return a value or not, and since you didn't include any links to this Youtube video you are working off of its impossible to tell what their intent is as well.

Assuming there is no need to return a value (such as whether or not this insert was successful or failed), then the fix to this specific error should be to change the word "Function" to "Sub". If the intent is to return a value, then you need a Return statement in the Function.

[StealthyCat]

When given errors like this, it is very important to read the error given. In this case the error outlines exactly what the issue is.

You have defined a Function. A Function needs to return a value. You have no Return statement. For the record, you also haven't defined a return type.

It isn't clear from what you've posted if there is a need to return a value or not, and since you didn't include any links to this Youtube video you are working off of its impossible to tell what their intent is as well.

Assuming there is no need to return a value (such as whether or not this insert was successful or failed), then the fix to this specific error should be to change the word "Function" to "Sub". If the intent is to return a value, then you need a Return statement in the Function.

Thanks for the help, man. It doesn't need to return a function so I will go and change that now. I did read the error but I'm very nooby and couldn't quite figure it out. Thank you!

[StealthyCat]

I highlighted the wrong error:

Severity Code Description Project File Line Suppression State
Error BC30311 Value of type 'MySqlConnection' cannot be converted to 'SQLiteConnection'. Tarantulapp v 1.0 C:\Users\taran\source\repos\Tarantulapp v 1.0\Tarantulapp v 1.0\frmAdd.vb 92 Active

[OptionBase1]

Again, read the error message and look at your code.

You are declaring SQLconn as a MySqlConnection object, but then trying to use that connection object in a SQLiteCommand object.

While I've never used either one, I'm fairly certain that MySQL and SQLite are two completely separate database systems. Not knowing which one you are using, I can't tell you how to fix it other than to say don't mix them like this. You need to declare objects related to the database system you are using.

[StealthyCat]

Again, read the error message and look at your code.

You are declaring SQLconn as a MySqlConnection object, but then trying to use that connection object in a SQLiteCommand object.

While I've never used either one, I'm fairly certain that MySQL and SQLite are two completely separate database systems. Not knowing which one you are using, I can't tell you how to fix it other than to say don't mix them like this. You need to declare objects related to the database system you are using.

Thanks once again. I have been following this tut and don't understand why he has no errors and I do haha.

[topshot]

Thanks once again. I have been following this tut and don't understand why he has no errors and I do haha.

There's no way the tut would have compiled as you had it written so he either misspoke/typed or you misheard/read.

[Shaggy Hiker]

I think that the only way you could have gotten as far as that first error is if you have Option Strict OFF. That's the default setting, and one that can seem pretty useful when you are starting out. After all, if you turn it to ON, you are quite likely to find a whole bunch of errors that weren't there before. However, those are real errors. With Option Strict OFF, the compiler will make do, as best it can, with what you give it. Quite often, it will do the right thing, but when it doesn't, it'll be much harder to figure out why not. With Option Strict ON, having a function without a return value would be an error, so you'd never get far...though maybe as far as you had already gotten. In any case, you'd have gotten a more correct error message, which would have been helpful.

Another point about Option Strict is that the code is more efficient, though you'll normally never see that. You write the same with Option Strict ON or OFF. Good code is good code, either way. What you can do with Option Strict OFF is not so good code, you just don't get scolded when you write it. Therefore, Option Strict ON just makes you better by not allowing you to be sloppy in some ways that you shouldn't be sloppy in. You can turn Option Strict ON for the project under Project | Properties on the Compile tab. You can also set it to default to On in the Tools | Options menu (but you have to find it, cause I always forget where it's located).

So, you might wonder why Option Strict is OFF if it makes you a better coder, and the code is more efficient? Heck, why do you need it at all? You need to be able to turn Option Strict OFF for the rare cases where you have to use late binding. As to why it defaults to off, my best guess is that MS thought it would make coding appear easier. It does. Up front, it appears easier....until you find a bug that having Option Strict OFF allowed through, cause those can be a real joy to track down. After all, the code works...after a fashion, it just didn't do what you thought it should do.

[jmcilhinney]

So, you might wonder why Option Strict is OFF if it makes you a better coder, and the code is more efficient? Heck, why do you need it at all? You need to be able to turn Option Strict OFF for the rare cases where you have to use late binding. As to why it defaults to off, my best guess is that MS thought it would make coding appear easier. It does. Up front, it appears easier....until you find a bug that having Option Strict OFF allowed through, cause those can be a real joy to track down. After all, the code works...after a fashion, it just didn't do what you thought it should do.

I suspect that making VB.NET more like VB6 by default was a factor too. Code being upgraded from VB6 would so often light up with Option Strict On.

[StealthyCat]

Thanks for your advice, guys. It's always appreciated. I have taken the stabalizers off and running on option strict ON. However, after fixing some of the code I have no errors now but it just won't do what it's suppoosed to. I have executed the SQL query in DB Browser and it works fine.

[jmcilhinney]

I have taken the stabalizers off and running on option strict OFF.

Do you mean Option Strict On?

THowever, after fixing some of the code I have no errors now but it just won't do what it's suppoosed to.

Then show us the code you have now and explain what it does do and how that differs from your expectation.

[StealthyCat]

Do you mean Option Strict On?

Then show us the code you have now and explain what it does do and how that differs from your expectation.

Yes, sorry. I meant on. I updated the OP with my current code. It creates a table and then SHOULD pass the title variable to the database (I am only doing it with one value until I can get it working.

[jmcilhinney]

Do you see the issue here?

    Public Sub InsertUsername(title As String, connectionstring As String, location As String)

        Try

        Catch ex As Exception


            Using sqlconn As New SQLiteConnection(connectionstring)
                Dim insertUserQuery As String = "INSERT INTO TarantulappDB(Name) VALUES(@title)"
                Dim cmd As New SQLiteCommand(insertUserQuery, sqlconn)
                cmd.Parameters.AddWithValue("@title", title)
                sqlconn.Open()
                cmd.ExecuteNonQuery()


            End Using
        End Try
    End Sub

Under what circumstances will that database code get executed? Hint: it won't. This is why you need to debug your code. If you had done then it would have been obvious that the code wasn't even being executed so it couldn't be failing.

[StealthyCat]

I don't understand why not though. This is why I posted the thread, dude.

[jmcilhinney]

What is the purpose of a Try block? What is the purpose of a Catch block? If you don't know, you should read up on that because you need to understand exception handling if you're going to implement it. If you do know then you know why your code isn't being executed.

[si_the_geek]

When you have a Try-Catch block, the code inside the Try section will run, and the code inside the Catch section will only run if an error (exception) happens in the Try section.

In this case you have no code inside the Try section, so it cannot generate an exception, so the code inside the Catch block will not run.

I updated the OP with my current code.

Please don't do that, it creates confusion and doesn't actually provide any benefit - it is better to post new information in new posts (unless you realise you missed something just after posting, and there are no more replies yet).

[StealthyCat]

When you have a Try-Catch block, the code inside the Try section will run, and the code inside the Catch section will only run if an error (exception) happens in the Try section.

In this case you have no code inside the Try section, so it cannot generate an exception, so the code inside the Catch block will not run.

Please don't do that, it creates confusion and doesn't actually provide any benefit - it is better to post new information in new posts (unless you realise you missed something just after posting, and there are no more replies yet).

Understandable. I don't know why I never saw that. I added that detering from the tutorial. I fixed it and still nothing happens. No messageboxes show.

 Try
            Using sqlconn As New SQLiteConnection(connectionstring)
                Dim insertUserQuery As String = "INSERT INTO TarantulappDB(Name) VALUES(@title)"
                Dim cmd As New SQLiteCommand(insertUserQuery, sqlconn)
                cmd.Parameters.AddWithValue("@title", title)
                sqlconn.Open()
                cmd.ExecuteNonQuery()
                MessageBox.Show("Your entry has been added to the database!")
            End Using

        Catch ex As Exception

            MessageBox.Show("Failed to add the entry to the database!")

        Finally

            MessageBox.Show("Completed!")

        End Try

[jmcilhinney]

You appear to be calling Server.insertUsername and expecting frmAdd.InsertUsername to be executed. Again, debug your code. We keep pointing things out that you should already know because you should have debugged the code. Place breakpoints in appropriate places and step through the code. If you don't know how to debug (which you probably should have mentioned by now, if that's the case) then you should starting learning here:

https://msdn.microsoft.com/en-us/lib...or=-2147217396

[StealthyCat]

You appear to be calling Server.insertUsername and expecting frmAdd.InsertUsername to be executed. Again, debug your code. We keep pointing things out that you should already know because you should have debugged the code. Place breakpoints in appropriate places and step through the code. If you don't know how to debug (which you probably should have mentioned by now, if that's the case) then you should starting learning here:

https://msdn.microsoft.com/en-us/lib...or=-2147217396

To be honest, I never even knew debuggin went any further than hitting F5 to run the code. I am guessing with this one, I have bitten off far more than I can chew as of yet but I have came to far to just abandon it.

Do you mean calling frmAdd.InsertUsername in the module?



I am so sorry for my noobiness on this. I will check out that article now.

[jmcilhinney]

If the method you want to call is in frmAdd then yes, you have to call the method on an instance of frmAdd, not on an instance of Server. If the InsertUsername method in frmAdd is the one you want to execute and it has three parameters then you need to pass three arguments to it when you call it. If it expects values for 'title', 'connectionString' and 'location' then you need to pass those values when you call it.

Maybe that method shouldn't be part of the form at all. Maybe you should have a form at all. It's hard to say. You've got a module with a Main method that doesn't call Application.Run, which is usually the case only for Console applications, not WinForms applications.

[StealthyCat]

Thanks for your continued patience. I (think) I have fixed the module. I was forgetting to pass the parameters to the module while adding them to frmAdd.insertUsername.

Module Module1

    Sub Main(title As String, location As String, connectionstring As String)
        Dim server As New Server
        server.createDataBase()
        frmAdd.InsertUsername(location, title, connectionstring)
        Application.Run()
    End Sub

End Module

I am guessing I have made my biggest mistake for following a tutorial that was for a console app and not for a Windows Form app. I did try and find one, but all I could see was "tutorials" that are just someone doing it with crap music in the background (I don't feel that merely copying someone coding helps. It always helps to know a little of what's going on, IMHO).

I have adapted my module a little to no avail. I wish I found a decent tutorial based on my needs before diving in.

[jmcilhinney]

Why use a module at all? Just create a WinForms app, have the user enter data into TextBoxes and then execute your code in the Click event handler of a Button. You can handle a Button Click, get those three values from TextBoxes and/or My.Settings and pass them on to the method from already inside the form.

[StealthyCat]

Why use a module at all? Just create a WinForms app, have the user enter data into TextBoxes and then execute your code in the Click event handler of a Button. You can handle a Button Click, get those three values from TextBoxes and/or My.Settings and pass them on to the method from already inside the form.

I'm sorry, I'm getting really confused here. Do you mean add that module code to the button code? It tells me server is not defined.

[jmcilhinney]

I think that you should start again with a new project. There's obviously stuff there that's irrelevant to what you're trying to do. Do as I suggested and create a Windows Forms Application project. Add appropriate controls for the user to enter the required data and add a Button to be clicked to initiate the data access code. In the Click event handler of the Button, gather the required data and call the method that performs the data access.

[Shaggy Hiker]

I'd go with that, too. If you started with a tutorial on a console app, I'm not sure of all the things that might have to change to make it work right as a forms app. Console apps just aren't that common, so starting with a forms app will likely be better.