How to initiate the call onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)?

Question

I need to upgrade my android sqlite database from version 1 to version 2. But I do not understand how the call public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)is initiated? How and when will this method be called? I don't understand where I pass the Version number 2?

[EDIT] I think I need to clarify this question. Here is my class:

public class MySQLiteOpenHelper  extends SQLiteOpenHelper {


public MySQLiteOpenHelper(Context context){
    super(context,
            Constants.DB_NAME,
            null,
            1);
}

public MySQLiteOpenHelper(Context context, int version){
    super(context, Constants.DB_NAME, null, version);
}

public MySQLiteOpenHelper(Context context, String name,
                               CursorFactory factory, int version) {
    super(context, Constants.DB_NAME, factory, version);
    // TODO Auto-generated constructor stub
}

public MySQLiteOpenHelper(Context context, String name,
                               CursorFactory factory, int version,
                               DatabaseErrorHandler errorHandler) {
    super(context, Constants.DB_NAME, factory, version, errorHandler);
    // TODO Auto-generated constructor stub
}
public void onCreate(SQLiteDatabase db) {
    // do creation stuff
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // do upgrade stuff
}
}

So, how does android trigger onUpgrade?

Answer 1

The SQLiteOpenHelper constructor takes a name and version number, and the helper will invoke the onCreate or onUpgrade callback as necessary. You need to maintain database version numbers yourself, bumping the version number when a schema change is necessary.

When you need to update your database from version 1 to version 2 just change

super(context, Constants.DB_NAME, null, 1);

to

super(context, Constants.DB_NAME, null, 2);

Then in your onUpgrade method you drop tables, add tables, or do anything else needed to upgrade from 1 to 2. onUpgrade will only be invoked the first time the SQLiteOpenHelper is instantiated after the version number changes.