Xamarin.Forms SQLite ,initialize data once on table creation - sqlite

Question

I am new in xamarin and I am trying to make xamarin.form app which contains sqlite database. So I know that the table is created once but also I have some records that I need to be in that table by default. I mean when table is created the data also must be initialized with it once. According to tutorial I have a class to handle the database called DataAccess.cs
class DataAccess : IDisposable
{
public void Dispose()
{
database.Dispose();
}
private SQLiteConnection database;
public ObservableCollection<DataModel> dataz { get; set; }
private static object collisionLock = new object();
public DataAccess()
{
database = DependencyService.Get<IConfig>().DbConnection();
database.CreateTable<DataModel>();
//database.Insert(new DataModel { Did = 1 , Data = "aaaa"});
//database.Insert(new DataModel { Did = 2, Data = "bbb" });
//database.Insert(new DataModel { Did = 3, Data = "ccc" });
this.dataz = new ObservableCollection<DataModel>(database.Table<DataModel>());
if (!database.Table<DataModel>().Any())
{
addNewData();
}
}
public void addNewData()
{
this.dataz.Add(new DataModel { Did = 1, Data = "aa" });
}
public void SaveData(DataModel record)
{
lock (collisionLock)
{
database.Insert(record);
}
}
public DataModel GetDataById(int id)
{
lock (collisionLock)
{
return database.Table<DataModel>().
FirstOrDefault(x => x.Did == id);
}
}
public List<DataModel> GeyAllData()
{
return database.Table<DataModel>().ToList();
}
}
Since the table is created in above class instructor. So I tried to initialized data there but data added to table on each run. So I confused how to initialize data on first run only.

Answer 1

You could go one of two ways.
1: Check if the table does not exist yet and if not, create it and add your data
var result = await conn.ExecuteScalarAsync<int>("SELECT count(*) FROM sqlite_master WHERE type='table' AND name='DataModel';", new string[] { });
if (result == 0)
{
await conn.CreateTableAsync<DataModel>();
// Insert your initial data
}
2: Always check if the data exists and insert it if it does not
FYI: Assuming Did is your PrimaryKey of DataModel
var row = await conn.FindAsync<Record>(1);
if (row == null)
{
// Insert the "Did = 1" row
}