Develop Reference

Android : Change SQLite DB on upgrade

I want to add a column to my existing database
However I'm imagining I'm in the scenario where people have already got a version of the code and database and I'm going to make the changes through a update on google play, therefore previous data cannot be lost
To create my database I used the following code;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_calculation);
db = openOrCreateDatabase("EJuiceData", Context.MODE_PRIVATE, null);
db.execSQL("create table if not exists Inventory(_id integer primary key autoincrement, NAME TEXT NOT NULL, AMOUNT TEXT, PRICE TEXT, AMOUNTLEFT TEXT, WEIGHT TEXT);");
....
I've looked around online and people are mentioning using the following command to update;
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (newVersion > oldVersion) {
db.execSQL("ALTER TABLE Recipe ADD COLUMN NOTES TEXT");
}
}
However onUpgrade is commented out stating the it isn't being called, also no where in my code have I stated what version of the database it is or given a new version
Anyone know how I get around this issue?
Thanks
EDIT;
From looking at the answers I've decided to try do this the most efficient way and what's seen as the best practice
So I've created a new Java Class called MyDBHelper which has the following
package com.sjhdevelopment.shaunharrison.myejuiceapp;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class MyDBHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "EJuiceData.db";
public static final int DATABASE_VERSION = 1;
public MovieDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public void onCreate(SQLiteDatabase database) {
database.execSQL("create table if not exists Recipe");
.....
}
#Override
public void onUpgrade(SQLiteDatabase database, int oldVersion, int newVersion) {
if (newVersion > oldVersion)
database.execSQL("ALTER TABLE Recipe ADD COLUMN NOTES TEXT");
onCreate(database);
}
}
So far I have an error on MovieDatabaseHelper stating 'invalid method declared; return type required

Are you using SQLiteOpenHelper ? If yes you must have a version you send to the super class from the constructor (see documentation)
Here is a code sample. The onUpgrade function will be called when the DATABASE_VERSION changes.
public class DatabaseHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "EJuiceData.db";
public DatabaseHelper (Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase database) {
database.execSQL("create table if not exists Inventory(_id integer primary key autoincrement, NAME TEXT NOT NULL, AMOUNT TEXT, PRICE TEXT, AMOUNTLEFT TEXT, WEIGHT TEXT);");
}
#Override
public void onUpgrade(SQLiteDatabase database, int oldVersion, int newVersion) {
if (newVersion > oldVersion) {
db.execSQL("ALTER TABLE Recipe ADD COLUMN NOTES TEXT");
onCreate(database);
}
}
}
EDIT
now you can get access your database using
DatabaseHelper helper = new DatabaseHelper(getContext());
helper.getReadableDatabase().query(...);
//or
helper.getWritableDatabase().insert(...);

#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (oldVersion < newVersion)
db.execSQL("DROP TABLE IF EXISTS '" + TABLE_NAME + "'");
onCreate(db);
}
}

You can extend SQLiteOpenHelper like below code, and new your helper class with version param which db version you want to open.
If you open db with version 1, and next time you open db with version 2, the onUpgrade method will be called with param ordVersion = 1 and newVersion = 2, then you can do something to upgrade your db schema here.
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
public class MyDBHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "mydata.db";
public static final int VERSION = 1;
private static SQLiteDatabase database;
public MyDBHelper(Context context, String name, CursorFactory factory,
int version) {
super(context, name, factory, version);
}
public static SQLiteDatabase getDatabase(Context context) {
if (database == null || !database.isOpen()) {
database = new MyDBHelper(context, DATABASE_NAME,
null, VERSION).getWritableDatabase();
}
return database;
}
#Override
public void onCreate(SQLiteDatabase db) {
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
onCreate(db);
}
}

SQLite database problems

I have veritabani.java and i create database in this class. Then i create object in mainactivity.java. But when i run app. the program dont move database.java so i cant create database how i can solve this problem.
veritabani.java
public class veritabani extends SQLiteOpenHelper {
private static final String VERİTABANİ_ADİ="kayit";
public veritabani(Context c)
{
super(c,VERİTABANİ_ADİ,null,2);
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE kayit(ilacadi TEXT);");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXIST kayit");
onCreate(db);
}
}
mainactivity.java
public class MainActivity extends Activity {
private veritabani v1;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home);
v1=new veritabani(this);
}
v1=new veritabani(this) doesnt work.

Try this code
public class DBAdapter
{
private static final String DATABASE_NAME = "GSDATA.db";
private static final int DATABASE_VERSION = 2;
private static final String CREATE_COVERPHOTO_TABLE = "CREATE TABLE IF NOT EXISTS COVERPHOTO (path Text,date DATE);";
private final Context context;
public String group;
private DatabaseHelper DBHelper;
private static SQLiteDatabase db;
public DBAdapter(Context ctx)
{
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}
private class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db)
{
db.execSQL(CREATE_COVERPHOTO_TABLE);
System.out.println("The Database is Created Here :");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// db.execSQL("DROP TABLE IF EXISTS calSimpleNote");
onCreate(db);
}
} // database helper class complete
// ---opens the database---
public DBAdapter open() throws SQLException {
db = DBHelper.getWritableDatabase();
return this;
}
// ---closes the database---
public void close() {
DBHelper.close();
db.close();
}
// and write below line in main activity
DBAdapter adapter = new DBAdapter(MainActivity.this);

I'm not sure what you mean by "the program dont move database.java" but i had issues with databases using SQLiteOpenHelper.
Actually, SQLiteOpenHelper calls " public void onCreate(SQLiteDatabase db)" only once, so if you change your tables between 2 launch, it won't be updated.
To solve this you have to manually delete the database by going into parameters / applications / [your_app] / erase data (or something like this) and try again.

Sqlite app not working on my device, but does on my emulator

In my app I have used Sqlite. When I test the app in the emulator it runs ok but when I test the app on my device, it fails because the Helper class not pass by the OnCreate method. My java code is below.
public static void startDB(Context context) {
DBHelper = new DataBaseHelper(context);
DBHelper.getWritableDatabase();
}
private static class DataBaseHelper extends SQLiteOpenHelper {
public DataBaseHelper(Context context) {
super(context, NOMBRE_BASE_DATOS, null, DATABASE_VERSION);
}
public void onCreate(SQLiteDatabase db) {
db.execSQL(USER_CREATE);
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
for (String table : ALL_TABLES) {
db.execSQL("DROP TABLE IF EXISTS " + table);
}
onCreate(db);
}
}

The framework only calls onCreate() if the database does not exist.
To force onCreate(), remove the old database file: clear your app's data in app manager, or just uninstall and reinstall.

alter table code in android...

following is the code that i used to alter my table but my app is crashing.
I have create this dbupdateadapter class separately. the records are being added, but the column is not added to the same table
public class dbupdateadapter {
public static final String TABLE_MEMBERID="memberid";
private static final String DATABASE_NAME="myfemmefab.db";
private static final String TABLE_NAME="registeration";
private static final int DATABASE_VERSION=2;
private static final String DATABASE_UPDATE="ALTER TABLE registeration ADD COLUMN(memberid TEXT);";
private static Context context1;
private dbhelper1 helper1;
private SQLiteDatabase sdb1;
public dbupdateadapter(Context con){
this.context1=con;
helper1=new dbhelper1(context1);
}
public class dbhelper1 extends SQLiteOpenHelper{
public dbhelper1(Context context){
super(context,DATABASE_NAME,null,DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase sdb1){
sdb1.execSQL(DATABASE_UPDATE);
}
#Override
public void onUpgrade(SQLiteDatabase sdb1,int oldver,int newver){
//android.util.Log.w("constants", "upgrading database will destroy the old data");
if(newver>oldver){
sdb1.execSQL(DATABASE_UPDATE);
}
//onCreate(sdb1);
}
}
public dbupdateadapter open() throws SQLException{
sdb1=helper1.getWritableDatabase();
return this;
}
void insertcoldata (String memberid){
ContentValues cv1=new ContentValues();
cv1.put(TABLE_MEMBERID, memberid);
sdb1.insert(TABLE_NAME, null, cv1);
}
public void close(){
helper1.close();
}
}

You should know that in
public void onCreate(SQLiteDatabase db ){ ... }
you should create your tables and populate them with some initial values and you didn't create table in your snippet of code.
for upgrating your tables you should use
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { ... }
Exactly from docs:
Called when the database needs to be upgraded. The implementation
should use this method to drop tables, add tables, or do anything else
it needs to upgrade to the new schema version.
Also have look at
SQL As Understood By
SQLite
Example of how to implement ALTER
TABLE

Use "ALTER TABLE registeration ADD memberid TEXT;"; or "ALTER TABLE registeration ADD COLUMN memberid TEXT;"; You have an error in syntax.
Where are you creating yout table? You are executing DATABASE_UPDATE in your onCreate().

Android Database Locate Data Before Application Starts

I need only select operation. Therefore the data should be inserted before the application starts. What is the best way to do this?

Use an subclass of SQLiteOpenHelper to access your db. The onCreate will be called once, when the database is created.
To use your db you can then do:
DBHelper db = new DBHelper(context);
db.getReadableDatabase().query(....);
db.close();
To extend SQLiteOpenHelper do something like (the sql for the table creation is not tested!):
public class DBHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "database.db";
private static final Integer DATABASE_VERSION = 1;
DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
/*
* Called ONCE on the very first db access (when the db file is created)
*/
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE mytable (_id PRIMARY KEY AUTOINCREMENT, value TEXT); \n" +
"INSERT INTO mytable (value) VALUES ('data'));");
}
/*
* Called every time you open a database
*/
#Override
public void onOpen(SQLiteDatabase db) {
}
/*
* Called ONCE if DATABASE_VERSION has changed since the last instantiation of DBHelper
*/
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}