What the version mean in the abstract class SQLiteOpenHelper of Android

Question

There is a parameter in the constructor of the virtual class SQLiteOpenHelper called version(like below shows)

public SQLiteOpenHelper(Context context, String name, CursorFactory factory, int version) {
        this(context, name, factory, version, null);
    }

What i want to know is what's the meaning of the version?Can anyone help me on this?

Answer 1

Its the Database version you ship with the Application. So in the future if you want to add a table or delete a column or anything which differs from the previous Database version. This version Number will come handy.

This is an example of how I manuplated DB on upgrades of my application: The method is defined by the framework, onUpgrade()

Class Level Variable:

private static final int DATABASE_VERSION = 4;

Check against the current version:

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            if (oldVersion < 2) {
                db.execSQL(DATABASE_CREATEX);
            }
            if (oldVersion < 3) {
                db.execSQL(DATABASE_CREATEC);
            }
            if (oldVersion < 4) {
                final String ALTER_TBL = "ALTER TABLE " + DATABASE_TABLE1
                        + " ADD COLUMN Vcost text;";
                final String ALTER_TBL1 = "ALTER TABLE " + DATABASE_TABLE1
                        + " ADD COLUMN Vmedicine text;";
                db.execSQL(ALTER_TBL);
                db.execSQL(ALTER_TBL1);

                final String ALTER_TBL2 = "ALTER TABLE " + DATABASE_TABLE2
                        + " ADD COLUMN Dcost text;";
                final String ALTER_TBL3 = "ALTER TABLE " + DATABASE_TABLE2
                        + " ADD COLUMN Dmedicine text;";
                db.execSQL(ALTER_TBL2);
                db.execSQL(ALTER_TBL3);

            }

        }

So it checks based on all versions of the DB and it acts according to the current version which is present on the device.