Starting out with vb.net and sqlite3...

[sub]

In the above example, I use a generic .getvalue that will take whatever type the data is and then it goes into a string. I suppsoe I could start to use specific datatypes. I know that VB6 is notorious for being slow when using variants. What do you all suggest?

I prefer to stick with real data types.

Also, I'd like to pump the results into an array. Is it correct to grab each column of each line, like this and add to array, or is there a way to get the query results already in a two dimensional array...

You could do something like this...

Declare some class to hold the various attributes:

Code:

public class Genre
{
   public int oid;
   public string genreName;
   public unsigned int argb;
}

then create a list and populare a instance of that class each time around the loop...

Code:

ArrayList genreList = new ArrayList();

    // load list of genre codes
    DbCommand command = dbProviderFactory.CreateCommand();
    command.Connection = connection;
    command.CommandText = "SELECT * from GENRE";    
    DbDataReader dataReader = command.ExecuteReader();
    while (dataReader.Read())
    {
        // create new instance
        Genre myGenre= new Genre();

        // load object from database settings        
        myGenre.oid = dataReader.GetInt32(dataReader.GetOrdinal("oid"));
        myGenre.name = dataReader.GetString(dataReader.GetOrdinal("genre_name"));
        .... etc

        // add object to list
        genreList.Add(myGenre);
    }
    dataReader.Close();

At the end of this you'd have a list of all the genre objects in the database.

[zehd]

I prefer to stick with real data types.

You could do something like this...

Declare some class to hold the various attributes:

Code:

public class Genre
{
   public int oid;
   public string genreName;
   public unsigned int argb;
}

then create a list and populare a instance of that class each time around the loop...

Code:

ArrayList genreList = new ArrayList();

    // load list of genre codes
    DbCommand command = dbProviderFactory.CreateCommand();
    command.Connection = connection;
    command.CommandText = "SELECT * from GENRE";    
    DbDataReader dataReader = command.ExecuteReader();
    while (dataReader.Read())
    {
        // create new instance
        Genre myGenre= new Genre();

        // load object from database settings        
        myGenre.oid = dataReader.GetInt32(dataReader.GetOrdinal("oid"));
        myGenre.name = dataReader.GetString(dataReader.GetOrdinal("genre_name"));
        .... etc

        // add object to list
        genreList.Add(myGenre);
    }
    dataReader.Close();

At the end of this you'd have a list of all the genre objects in the database.

Wow. I think this is something I've been wanting to learn forever. Thanks. Now I just have to sort through it. (It's fun)

So each record a new 'myGenre' is loaded with data, and then added to the genrelist array collection...

In the meanwhile, I discovered how to iterate columns, so in theory I could use that to count them out. But I like your way.

It doesn't look reusable though. I would have to copy and adjust this code for each query set I wanted to play with though.

If that's fast and efficient, that's what I'll do

[sub]

It doesn't look reusable though. I would have to copy and adjust this code for each query set I wanted to play with though.

You can create generic stuff if you want, but I prefer to deal with real types. For example, I have a channel manager object that has calls like ChannelManager.GetChannels(), which will return an ArrayList of channel objects. These Channels have attributes like Name, Number etc. This call and the channels are then used throughout the app. Thats pretty good reuse in my book, even though its not really what you mean.

[zehd]

You can create generic stuff if you want, but I prefer to deal with real types. For example, I have a channel manager object that has calls like ChannelManager.GetChannels(), which will return an ArrayList of channel objects. These Channels have attributes like Name, Number etc.

THat sounds pretty organized. I like it.

[zehd]

I've got it mostly working, but I have an infinity error when it hist a record with argb not filled in, probably null. I guess I'll have to test for null, but I can't find the isnull function. Oh well. That's life with something new...

[sub]

From memory its something like:

Object argb = dataReader.GetObject(dataReader.GetOrdinal("argb"));
if (Convert.IsDBNull(argb) == false)
{
argb = Convert.ToInt32(argb);
}

[zehd]

From memory its something like:

Object argb = dataReader.GetObject(dataReader.GetOrdinal("argb"));
if (Convert.IsDBNull(argb) == false)
{
argb = Convert.ToInt32(argb);
}

Yuck

[whurlston]

in C#, you just do:

Code:

if (!object == null)
{
    // Process stuff here.
    // The exclamation point means "is not"
}

Not sure offhand the VB syntax.

Edit: I see sub's reply now.

[zehd]

Yuck

My SQL browser says that the argb_color column is actually a string field. Is that right?

[psycik]

"Is nothing" in vb.net is equivalent to "== null"

And "if (not object is nothing) then" is the not clause.

But sometimes DB stuff doesn't recognise null, and needs the DBNull. Which is probably why sub has done it his way.