SQLite add column, keep data

Question

I have a database with 4 columns:

@Override public void onCreate(SQLiteDatabase database) {         database.execSQL("CREATE TABLE " + DATABASENAME + " (name TEXT, latitude REAL, longitude REAL, country TEXT);"); } 

Now I want to add another column, but keep the rows that are already in the database. How should I do this? I can't find any useful references to this.

@Override public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {     //What to do here? } 

EDIT

I have modified my onCreate to:

@Override public void onCreate(SQLiteDatabase database) {     database.execSQL("CREATE TABLE " + DATABASENAME + " (name TEXT, latitude REAL, longitude REAL, country TEXT, code TEXT);"); } 

and my onUpgrade to:

@Override public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {     Logger.log("Updating userstations database from " + arg1 + " to " + arg2 + ".");     if (arg1 == 2 && arg2 == 3) {         db.execSQL("ALTER TABLE " + DATABASENAME + " ADD COLUMN code TEXT;");     } else if(arg1 == 1){         db.execSQL("DROP TABLE IF EXISTS " + DATABASENAME);     }     onCreate(db); } 

However, now I get this stacktrace:

10-01 21:24:19.581: ERROR/Database(21434): Failure 1 (table userstations already exists) on 0x19c378 when preparing 'CREATE TABLE userstations (name TEXT, latitude REAL, longitude REAL, country TEXT, code TEXT);'. 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434): Couldn't open userstations for writing (will try read-only): 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434): android.database.sqlite.SQLiteException: table userstations already exists: CREATE TABLE userstations (name TEXT, latitude REAL, longitude REAL, country TEXT, code TEXT); 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.database.sqlite.SQLiteDatabase.native_execSQL(Native Method) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1763) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.databases.UserStationsOpenHelper.onCreate(UserStationsOpenHelper.java:25) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.databases.UserStationsOpenHelper.onUpgrade(UserStationsOpenHelper.java:36) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:132) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:187) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.databases.UserStationsOpenHelper.getStations(UserStationsOpenHelper.java:43) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.Data.readUserStations(Data.java:369) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.Data.getUserStations(Data.java:210) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.stationstab.StationsActivity.newStations(StationsActivity.java:190) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.stationstab.StationsActivity.refresh(StationsActivity.java:129) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.stationstab.StationsActivity.onCreate(StationsActivity.java:108) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1722) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.ActivityThread.startActivityNow(ActivityThread.java:1598) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.stationstab.StationsActivityGroup.onCreate(StationsActivityGroup.java:38) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1722) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.ActivityThread.startActivityNow(ActivityThread.java:1598) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:654) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.widget.TabHost.setCurrentTab(TabHost.java:326) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.widget.TabHost.addTab(TabHost.java:216) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.TreinVerkeer.setupTab(TreinVerkeer.java:131) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.TreinVerkeer.initTabs(TreinVerkeer.java:108) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.myapp.myapp.TreinVerkeer.onCreate(TreinVerkeer.java:62) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1722) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1784) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.ActivityThread.access$1500(ActivityThread.java:123) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:939) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.os.Handler.dispatchMessage(Handler.java:99) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.os.Looper.loop(Looper.java:123) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at android.app.ActivityThread.main(ActivityThread.java:3835) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at java.lang.reflect.Method.invokeNative(Native Method) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at java.lang.reflect.Method.invoke(Method.java:507) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599) 10-01 21:24:19.611: ERROR/SQLiteOpenHelper(21434):     at dalvik.system.NativeStart.main(Native Method) 10-01 21:24:19.621: DEBUG/AndroidRuntime(21434): Shutting down VM 10-01 21:24:19.621: WARN/dalvikvm(21434): threadid=1: thread exiting with uncaught exception (group=0x4018a560) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434): FATAL EXCEPTION: main 10-01 21:24:19.641: ERROR/AndroidRuntime(21434): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myapp.myapp/com.myapp.myapp.TreinVerkeer}: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myapp.myapp/com.myapp.myapp.stationstab.StationsActivityGroup}: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myapp.myapp/com.myapp.myapp.stationstab.StationsActivity}: android.database.sqlite.SQLiteException: Can't upgrade read-only database from version 2 to 3: /data/data/com.myapp.myapp/databases/userstations 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1768) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1784) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.ActivityThread.access$1500(ActivityThread.java:123) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:939) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.os.Handler.dispatchMessage(Handler.java:99) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.os.Looper.loop(Looper.java:123) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.ActivityThread.main(ActivityThread.java:3835) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at java.lang.reflect.Method.invokeNative(Native Method) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at java.lang.reflect.Method.invoke(Method.java:507) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at dalvik.system.NativeStart.main(Native Method) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434): Caused by: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myapp.myapp/com.myapp.myapp.stationstab.StationsActivityGroup}: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myapp.myapp/com.myapp.myapp.stationstab.StationsActivity}: android.database.sqlite.SQLiteException: Can't upgrade read-only database from version 2 to 3: /data/data/com.myapp.myapp/databases/userstations 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1768) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.ActivityThread.startActivityNow(ActivityThread.java:1598) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:654) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.widget.TabHost.setCurrentTab(TabHost.java:326) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.widget.TabHost.addTab(TabHost.java:216) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at com.myapp.myapp.TreinVerkeer.setupTab(TreinVerkeer.java:131) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at com.myapp.myapp.TreinVerkeer.initTabs(TreinVerkeer.java:108) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at com.myapp.myapp.TreinVerkeer.onCreate(TreinVerkeer.java:62) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1722) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     ... 11 more 10-01 21:24:19.641: ERROR/AndroidRuntime(21434): Caused by: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myapp.myapp/com.myapp.myapp.stationstab.StationsActivity}: android.database.sqlite.SQLiteException: Can't upgrade read-only database from version 2 to 3: /data/data/com.myapp.myapp/databases/userstations 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1768) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.ActivityThread.startActivityNow(ActivityThread.java:1598) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at com.myapp.myapp.stationstab.StationsActivityGroup.onCreate(StationsActivityGroup.java:38) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1722) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     ... 22 more 10-01 21:24:19.641: ERROR/AndroidRuntime(21434): Caused by: android.database.sqlite.SQLiteException: Can't upgrade read-only database from version 2 to 3: /data/data/com.myapp.myapp/databases/userstations 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:199) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at com.myapp.myapp.databases.UserStationsOpenHelper.getStations(UserStationsOpenHelper.java:43) 10-01 21:24:19.641: ERROR/AndroidRuntime(21434):     at com.myapp.myapp 

Answer 1

Please see this page for the syntax to create a new column on a table. Basically it is:

ALTER TABLE mytable ADD COLUMN mycolumn TEXT 

In your onUpgrade method, it would look something like this:

@Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {     String upgradeQuery = "ALTER TABLE mytable ADD COLUMN mycolumn TEXT";     if (oldVersion == 1 && newVersion == 2)          db.execSQL(upgradeQuery); } 

Answer 2

A better approach

@Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {     switch (oldVersion) {         case 1:             db.execSQL(SQL_MY_TABLE);           case 2:             db.execSQL("ALTER TABLE myTable ADD COLUMN myNewColumn TEXT");      } } 

Lets say in case 1, you upgraded to db version 2. You created a new table but forgot the myNewColumn you will see in case 2. What this will do is if you change the db version to 3, case 2 will get ran if its upgrading from 2 to 3.