Develop Reference

Android SQLite Database with Inserted row

I am trying to make an application that comes with some pre inserted rows in the database for the user to use. I have looked at lots of different questions here relating to the same topic but I am still slightly confused.
At the moment I have a DB class that contains all the table creates and functions that interact with the different tables. From my understanding of reading around the best way to have pre populated data is creating a file in the assets folder and calling that to insert the data.
As per the help of the answers below I have made some progress, I am no facing the error of not being able to access the sql file in the res folder or even in the raw folder. I have added below the snippet from the class were I am creating my tables and then attempting to call sql file using the runScript method. I have also added the directory layout of both res and raw.
Methods
public void runScript(SQLiteDatabase db, int rawResourceId, boolean okToFail)
{
Log.i("DB", "Running SQL script");
InputStream in = context.getResources().openRawResource(rawResourceId);
Scanner s = new Scanner(in);
String sql = "";
while (s.hasNext())
{
sql += " " + s.nextLine();
if (sql.endsWith(";"))
{
try
{
db.execSQL(sql);
}
catch (SQLException e)
{
if (okToFail)
Log.w(getClass().getSimpleName(), e.getMessage());
else
throw e;
}
sql = "";
}
}
s.close();
}
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db)
{
try {
db.execSQL(CREATE_TABLE_RECIPES);
db.execSQL(CREATE_TABLE_INGREDIENTS);
db.execSQL(CREATE_TABLE_CONTENTS);
db.execSQL(CREATE_TABLE_SHOPPING);
db.execSQL(CREATE_TABLE_DIRECTIONS);
db.execSQL(CREATE_TABLE_FOOD_CATEGORY);
db.execSQL(CREATE_TABLE_FOOD_LIST);
db.execSQL(CREATE_TABLE_BARCODE);
db.execSQL(CREATE_TABLE_FAVOURITES);
runScript(db, R.raw.pocket_chef_db.sql); ------Cannot resolve symbol raw
//runScript(db, R.res.database.pocket_chef_db.sql) ------Cannot resolve symbol res
} catch (SQLException e) {
e.printStackTrace();
}
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS contacts");
onCreate(db);
}
}
Res - Path to sql
Res->database->pocket_chef_db.sql
Raw - Path to sql
Raw->pocket_chef_db.sql

The way I did this is create a .sql file and put it in the res/raw folder.
This script contains DROP IF EXISTS statements to drop all existing tables and then does all the CREATE TABLE statements. If course you can add INSERT statements as well.
To run this script I wrote the following method in my SQLOpenLiteHelper extension class. Your rawResourceId will be R.raw.db_create, if your file is called db_create.sql.
/**
* Runs the provided raw resource as a script that doesn't return anything.
*
* Warning: this is a NOT a foolproof SQL script interpreter.
*
* Please note:
* All terminators (;) must be at the end of a line.
*
*
* #param db
* #param rawResourceId
*/
public void runScript(SQLiteDatabase db, int rawResourceId, boolean okToFail)
{
Log.i(getClass().getSimpleName(), "Running SQL script");
InputStream in = context.getResources().openRawResource(rawResourceId);
Scanner s = new Scanner(in);
String sql = "";
while (s.hasNext())
{
sql += " " + s.nextLine();
if (sql.endsWith(";"))
{
try
{
db.execSQL(sql);
}
catch (SQLException e)
{
if (okToFail)
Log.w(getClass().getSimpleName(), e.getMessage());
else
throw e;
}
sql = "";
}
}
s.close();
}

Try the SqliteAssetHelper from this link https://github.com/jgilfelt/android-sqlite-asset-helper to implement your requirement.

SQLiteOpenHelper: onCreate() method not called on physical device

I have done many tests on an android emulator running in version 4.4.
On my app I create a sqlite database with one table using SQLiteOpenHelper:
package com.findwords.modeles;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import com.findwords.MainActivity;
import com.findwords.controleurs.MenuController;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* Created by louk on 02/01/14.
*/
public class DictionaryDbHelper extends SQLiteOpenHelper{
// declare constants fields
private static final String DB_PATH = "/data/data/com.findwords/databases/";
private static final String DB_NAME = "dictionary_db";
private static final int DB_VERSION = 1;
// declared constant SQL Expression
private static final String DB_CREATE =
"CREATE TABLE dictionary ( " +
"_id integer PRIMARY KEY AUTOINCREMENT, " +
"word text NOT NULL, " +
"definition text NOT NULL, " +
"length integer NOT NULL " +
");";
private static final String DB_DESTROY =
"DROP TABLE IF EXISTS dictionnary";
/*
* constructor
*/
public DictionaryDbHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
/**
* Creates a empty database on the system and rewrites it with your own database.
* */
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if(dbExist){
//do nothing - database already exist
}else{
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
/**
* Check if the database already exist to avoid re-copying the file each time you open the application.
* #return true if it exists, false if it doesn't
*/
private boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//database does't exist yet.
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
}
/**
* Copies your database from your local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled.
* This is done by transfering bytestream.
* */
private void copyDataBase() throws IOException{
//Open your local db as the input stream
InputStream myInput = MenuController.getInstance().getMainActivity().getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
/*
* (non-Javadoc)
* #see android.database.sqlite.SQLiteOpenHelper#onCreate(android.database.sqlite.SQLiteDatabase)
*/
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(DB_CREATE);
try {
createDataBase();
} catch (IOException e) {
e.printStackTrace();
}
}
/*
* (non-Javadoc)
* #see android.database.sqlite.SQLiteOpenHelper#onUpgrade(android.database.sqlite.SQLiteDatabase, int, int)
*/
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL(DB_DESTROY);
onCreate(db);
}
}
Moreover I have written an adapter with a method open:
/*
* open database connection
*/
public DictionaryDbAdapter open() throws SQLException {
mDbHelper = new DictionaryDbHelper(mContext);
mDb = mDbHelper.getWritableDatabase();
return this;
}
It's working well on the emulator so the onCreate() method of the SQLiteOpenHelper class is called and create the database, but is not called on my phone (Google Nexus 5).
My phone is not rooted so I can't access the folder /data/data/com.myapp/databases .
However I want this application to work on any phone so I don't want to root my phone.
Thanks in advance to anyone who could help me.

Let i try to explain you some things.
In an application to connect to the database , we specify the name and version of the database . In this situation, the following may occur :
1) There is no database . This may be for example in the case of initial setting program. In this case, the application itself must create the database and all the tables in it. And further, it is already working with the newly created database.
2) Database exists, but its version is outdated. It may be the case update. For example a new version of the program need additional fields in the old tables or new tables . In this case, the application must update existing tables and create new ones if necessary.
3) There is a database and its actual version . In this case, the application successfully connects to the database and running.
As you know , the phrase " application must " tantamount to the phrase " the developer must ", ie it is our task . To handle the situations described above , we need to create a class that inherits for SQLiteOpenHelper. Call it DBHelper. This class will provide us with methods to create or update the database in case of their absence or obsolescence.
onCreate - a method that will be called if the database to which we want to connect - does not exist(it's your case)

The onCreate method is called only for the first time - when the DB is actually created. So if you uninstall your app and then install it again - it will get called, but if you install on top of the existing copy onCreate will not be called (since the DB already exists)

As #Asahi said, Database is only created only if you reinstall the app. But since you said that My phone is not rooted so I can't access the folder /data/data/com.myapp/databases, I want to point out that you can connect your mobile to the computer, install the correct USB drivers and use DDMS to see the file structure of your mobile phone. There you can see the database of your app along with the Shared Preferences and other files.
PS :- To see all the folder of real device on ddms you need root access. If your device is not rooted and you don't want to root your one then you can install the device on emulator which shows all folders in DDMS.

Replace sql database but keep old records

After a lot of work I managed to build my first app, but I stick with one question. For my app I am using a sql database.. Suppose I want to add 30 records to a certain table. How is it possible that when I put a new version in the android market with a new sql table to use this one for the future, but to keep the records of the previous database?
Does it has to do something with:
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
EDIT
my databasehelper code:
public class DataBaseHelper extends SQLiteOpenHelper {
private static String DB_PATH = "/data/data/com.test.com/databases/";
private static String DB_NAME = "quizDb";
private SQLiteDatabase myDataBase;
private final Context myContext;
private Cursor c;
static int numberOfLevels = 10;
private final static int DB_VERSION = 2; // = until level 10
/**
* Constructor Takes and keeps a reference of the passed context in order to
* access to the application assets and resources.
*
* #param context
*/
public DataBaseHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
this.myContext = context;
}
/**
* Creates a empty database on the system and rewrites it with your own
* database.
* */
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (!dbExist) {
// By calling this method and empty database will be created into
// the default system path
// of your application so we are gonna be able to overwrite that
// database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
/**
* Check if the database already exist to avoid re-copying the file each
* time you open the application.
*
* #return true if it exists, false if it doesn't
*/
private boolean checkDataBase() {
File dbFile = new File(DB_PATH + DB_NAME);
return dbFile.exists();
}
/**
* Copies your database from your local assets-folder to the just created
* empty database in the system folder, from where it can be accessed and
* handled. This is done by transfering bytestream.
* */
private void copyDataBase() throws IOException {
// Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
// Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
// transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException {
// Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READONLY);
}
#Override
public synchronized void close() {
if (c != null)
c.close();
if (myDataBase != null)
myDataBase.close();
super.close();
}
#Override
public void onCreate(SQLiteDatabase db) {
}
public File getDatabasePath(String name) {
File file = myContext.getDatabasePath(name);
return file;
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("ATTACH DATABASE ? as AttachedDB",
new String[] { getDatabasePath("quizDbNew").getPath() });
db.execSQL("INSERT OR IGNORE INTO questions (_id, file, answer, level) SELECT _id, file, answer, level FROM AttachedDB.questions");
db.execSQL("DETACH AttachedDB");
}

The concept of using "DROP TABLE" in onUpgrade() is as primitive as database management gets, however more useful techniques require more SQL savvy. A smarter way to upgrade your databases by using "ALTER TABLE" to add new columns or otherwise finagle the old data into your new schema.
Addition
Below in the comments you stated (more or less):
I want to copy the content from my backup file of Db v1 into my current Db v2
So let's set up a couple hypothetical tables:
Database Version One (DBv1):
CREATE TABLE Foo(_id INTEGER PRIMARY KEY, bar TEXT, bar2 TEXT, bar3 TEXT);
Database Version Two (DBv2):
CREATE TABLE Foo(_id INTEGER PRIMARY KEY, bar2 TEXT, bar4 INTEGER);
First let's see a regular upgrade from DBv1 to DBv2. SQLite only supports ADD COLUMN and RENAME TO, not REMOVE COLUMN or anythings else. So we have to re-create the entire table:
#Override // DBv1 => DBv2
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("ALTER TABLE Foo RENAME TO OldFoo");
db.execSQL("CREATE TABLE Foo(_id INTEGER PRIMARY KEY, bar2 TEXT, bar4 INTEGER)");
db.execSQL("INSERT INTO Foo (_id, bar) SELECT _id, bar2 FROM OldFoo");
db.execSQL("DROP TABLE OldFoo");
}
Again this created a table with DBv2's schema and kept all of the valid, existing data from DBv1 by inserting the appropriate columns into DBv2. (Then it removed the old data by dropping the old table.)
You have wisely chosen to backup your database over time in a separate file, but now you want to bring the old data into the new table schema. To start make sure that your backup SQLite file is in the same directory as your current SQLite file (data/data/<reverse.package.name>/databases/). It will obviously need a unique name, let's call it DBBackup. Now let's attach DBBackup to your current database and perform a similar action from above:
// DBBackupv1 => DBv2
public void restore(SQLiteDatabase db) {
db.execSQL("ATTACH DATABASE ? as AttachedDB", new String[] {getDatabasePath("DBBackup").getPath()});
db.execSQL("INSERT OR IGNORE INTO Foo (_id, bar2) SELECT _id, bar2 FROM AttachedDB.Foo");
db.execSQL("DETACH AttachedDB");
}
I used INSERT OR IGNORE to restore any rows that were deleted but left the current existing rows untouched. You can use INSERT OR REPLACE to revert to the backed up version. There are many more options to suit your needs.

Multiple database operations from sql query

I have two instances of SQLiteDatabase database. And I need to copy data from one to another.
I need to execute this query:
INSERT INTO `toDB`.`tableName` SELECT * FROM `fromDB`.`tableName`
so, How can I do this my database instances? How to replace toDB and fromDB ?

Never tried that but it should work this way:
you have to ATTACH the other database at SQLite level so sqlite can access it directly.
For example you open the database that shall be the toDB and you issue the following command (via execSQL)
ATTACH DATABASE '/data/data/your.package/databases/dbname.db' AS fromDB
you should have access to the other database now and can do
INSERT INTO main.tableName SELECT * FROM fromDbB.tableName
the database you opened originally has the name "main" automatically.
You can and should get the path to your databases via Context#getDatabasePath since there is no guarantee that this path is the same on all devices.

Yes, you can do this as following:
DatabaseHelper dbHelper = DatabaseHelper.create(CMOSApplication.getInstance());
SQLiteDatabase db = null;
try {
db = dbHelper.getWritableDatabase();
db.execSQL("attach database ? as oldDB",
new String[] { CMOSApplication.getInstance().getDatabasePath("cmos_database").getPath() });
db.execSQL("insert into task select * from oldDB.task");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if(db != null){
try {
db.execSQL("detach oldDB");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

How do i upgrade my pre-populated sqlite database on my device without re-creating tables?

I have my code below. It correctly reads my sqlite database file(that i have already created using the SQLite Database Browser) in my assets folder - moves it to the /data/data/packagename/databases/ path on my device then i am able to use a query and cursor to get my information and it works great. Code here:
public class DatabaseHelper extends SQLiteOpenHelper {
private Context myDbContext;
private static String dbName = "restaurant.db";
private static String outfilePath = "/data/data/dev.mypackage.com/databases/";
private static String path = outfilePath + dbName;
private static SQLiteDatabase db;
public DatabaseHelper(Context context){
super(context, dbName, null, 2);
this.myDbContext = context;
db = openDb();
String s = "select * from menu";
Cursor c = db.rawQuery(s, null);
Log.e("DB Constructor Row count", String.valueOf(c.getCount()).toString());
while(c.moveToNext()){
Log.e("DB Constructor", c.getString(c.getColumnIndex("category")));
Log.e("DB Constructor", c.getString(c.getColumnIndex("menuItem_id")));
Log.e("DB Constructor", c.getString(c.getColumnIndex("title")));
Log.e("DB Constructor", c.getString(c.getColumnIndex("desc")));
Log.e("DB Constructor", c.getString(c.getColumnIndex("price")));
Log.e("DB Constructor", c.getString(c.getColumnIndex("icon")));
}
c.deactivate();
c.close();
}
private void copyDataBase(File dbFile) throws IOException {
try{
InputStream dbStream = myDbContext.getAssets().open(dbName);
OutputStream newDbFile = new FileOutputStream(outfilePath + dbName);
byte[] buffer = new byte[1024];
int length;
while((length = dbStream.read(buffer)) > 0){
newDbFile.write(buffer);
}
newDbFile.flush();
newDbFile.close();
dbStream.close();
}
catch(IOException e){
throw new IOException("trying to copy the database - ERROR: " + e.getMessage());
}
}
private SQLiteDatabase openDb() throws SQLiteException{
File dbFile = myDbContext.getDatabasePath(dbName);
if(!dbFile.exists()){
Log.e("openDb", "file does not exist");
try {
copyDataBase(dbFile);
} catch (IOException e) {
throw new RuntimeException("Error creating source database", e);
}
}
return SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READONLY);
}
public void loadRestaurantInfo(){
}
#Override
public void onCreate(SQLiteDatabase db){
// TODO Auto-generated method stub
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
Now i had to go back and add a row of information to one of the tables(in the database in the assets folder), using the SQLite Brower, - but that is not being reflected in my cursor output - I understand why this is happening - because if(!dbFile.exists()) fails so there is no copying to be done. So my question is - is what code do i need to add to make this work? I never created the tables with code so i dont see how useful the onUpgrade method is going to be for me.

You have three options:
Use onUpgrade() (preferred)
Delete the existing database and copy the new one (not a good idea)
Copy the data in the existing database, delete the existing database, copy the new database, insert data from old database into new database (too much work when the new database schema can be upgraded in onUpgrade).
So, to answer your question, you upgrade your database in onUpgrade() without having to recreate any tables.
On the other hand, if you just added a new row to a particular table, the database schema has not changed and you can just insert the new row at runtime... of course, not knowing what your application's purpose is this may not be a good idea as you can easily lose track of changes to your "static" database.

The "right" way to do things is quite different from how you've set out. Rather than go there, I'll assume you want to keep your current method of creating your database and I'll offer a suggestion to work with it. Add a table to your database which has a single row of meta data, which will include the database version (as well as anything else you like). If the database file already exists, open it and check the version. If the version is old, close it and replace it.