SQLite Implementation


We’ve all been in situations where we needed to store data on a device within a specific application. Not only should the database reside on the machine where the application is running, but it also shouldn’t matter if we have multiple instances connecting to the database. In other words, we only need to provide data to one specific application. For a desktop solution, we could easily setup MSSQL or MySQL; but what if the aforementioned application is running on a mobile device? Similarly, what if we need our database to be portable between devices?

SQLite solves all of these requirements. SQLite is a light-weight and self-contained SQL database engine that enables us to put a database on just about any type of device. Also, since SQLite uses a flat-file for the actual database, there is no worry of a complicated setup. Typically, a SQLite installation consists of a flat-file, the SQLite library (in a format such as a .dll file), and the actual application that will be using the database; That’s it!

Perhaps now you’re thinking, “That’s all good, but how complicated is SQLite to code for?” The answer to that question is, “Not complicated at all!” To demonstrate the simplicity of implementing SQLite, consider the following C# code snippet:

string connectionString = "@"Data Source="C:exampledb.sqlite3"
 SQLiteConnection db = new SQLiteConnection(connectionString);

db.Open();

SQLiteCommand query = db.CreateCommand();
 query.CommandText = "SELECT * FROM tblExampleTable";

DataTable dtExampleTable = new DataTable();
 SQLiteDataReader dr;
 dr = query.ExecuteReader(CommandBehavior.CloseConnection);
 dtExampleTable.Load(drSqliteReader);

Now, let’s discuss what this code actually does. In the first line, we’re instantiating a new instance of SQLiteConnection. The argument passed into the constructor provides the location of the flat-file that we will be using for the database. In the case of this example, I used the extension .sqlite3 for my flat-file. Because of the way the file is parsed, the actual extension that you use is irrelevant. Nonetheless, providing a meaningful extension (such as .sqlite3) can give a good indication to others of what the file is as well as the version of SQLite being used.

From here, we call the Open() method on our newly-created connection object. This method simply tells SQLite to go ahead and connect to our database, whose connection string was passed to the SQLiteConnection its constructor.

Next, using our connection object, we create a SQLiteCommand that will be used to provide the engine with our actual query that we will be running. After assigning said query, using query.CommandText, we instantiate an instance of a standard .NET DataTable. After that, we simply execute our query that we just defined and load the results into the DataTable object that we created.

Voila! We now have an object that contains results that we queried straight from a SQLite flat-file. We didn’t have to perform any complicated code (like serialization between .NET and SQLite) to get this going. You would of course want to continue beyond our short code example (e.g. displaying the data in a GridView in ASP.NET), but for the purpose of this blog, that’s all we need.


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