Android Sqlite Onupgrade Not Working

пятница 27 марта

Testing SQL Upgrades on Android

I realized that I can actually test these changes locally on my desktop, using the version of sqlite3 that is already on my OS X laptop. (You can probably get similar results by having your test code manipulate the sqlite on the phone/emulator, but I found working with the local database to be easier.)

The problem

The first thing to do to keep from going insane is to log previous versions of your schema. I store them in constants in my test code, so I can easily replay them:The upgrade code looks like this:(In fact this code already has a bug in it.)

Step 1: Intercept sqlite calls

Intercepting the calls lets you replace them for testing. I used an interface to do this:Since SQLiteOpenHelper onUpgrade won't be happy taking your new ISQLite interface, you'll also need to route your SQLiteOpenHelper calls to a SQLiteOpenHelperDelegate. Then have your delegate's onUpgrade calls the database through ISQLiteDatabase instead of calling sqlite directly.

Step 2: Create a test double that uses your local sqlite3

The double will call your desktop instance of sqlite. It's a few lines of Java to execute the sqlite3 on the command line with your SQL, and grab any output:

To inspect the database, I added 'dumpSchema' and 'dumpTable' methods, which call '.schema' and 'SELECT * FROM ' respectively.

Step 3: Write your test

In your test, setup the previous version of the schema, and populate it with test rows.

Step 4: Fix bugs

Oops, upgrading from version 2 shouldn't add the publisher column! The line should read 'oldVersion 3'. I've also found more subtle bugs with these tests, such as missing 'NOT NULL' or 'DEFAULT' column attributes.

SQLite is an open-source relational database i.e. used to perform database operations on android devices such as storing, manipulating or retrieving persistent data from the database.

It is embedded in android bydefault. So, there is no need to perform any database setup or administration task.

Android sqlite onUpgrade not working. Ask Question Asked 6 years, 10 months ago. Import android.database.sqlite.SQLiteException; import android.database.sqlite.SQLiteOpenHelper; import android.util.Log; public class DataBaseHelper extends SQLiteOpenHelper //The Android's default system path of the application's database. Problem: You want to provide an orderly upgrade to the SQLite database schema on your. Implement the onUpgrade method in your SQLiteHelper subclass.

Here, we are going to see the example of sqlite to store and fetch the data. Data is displayed in the logcat. For displaying data on the spinner or listview, move to the next page.

SQLiteOpenHelper class provides the functionality to use the SQLite database.

SQLiteOpenHelper class

The android.database.sqlite.SQLiteOpenHelper class is used for database creation and version management. For performing any database operation, you have to provide the implementation of onCreate() and onUpgrade() methods of SQLiteOpenHelper class.

Constructors of SQLiteOpenHelper class

There are two constructors of SQLiteOpenHelper class.

Constructor	Description
SQLiteOpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version)	creates an object for creating, opening and managing the database.
SQLiteOpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version, DatabaseErrorHandler errorHandler)	creates an object for creating, opening and managing the database. It specifies the error handler.

Methods of SQLiteOpenHelper class

There are many methods in SQLiteOpenHelper class. Some of them are as follows:

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Method	Description
public abstract void onCreate(SQLiteDatabase db)	called only once when database is created for the first time.
public abstract void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)	called when database needs to be upgraded.
public synchronized void close ()	closes the database object.
public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion)	called when database needs to be downgraded.

SQLiteDatabase class

It contains methods to be performed on sqlite database such as create, update, delete, select etc.

Methods of SQLiteDatabase class

There are many methods in SQLiteDatabase class. Some of them are as follows:

Method	Description
void execSQL(String sql)	executes the sql query not select query.
long insert(String table, String nullColumnHack, ContentValues values)	inserts a record on the database. The table specifies the table name, nullColumnHack doesn't allow completely null values. If second argument is null, android will store null values if values are empty. The third argument specifies the values to be stored.
int update(String table, ContentValues values, String whereClause, String[] whereArgs)	updates a row.
Cursor query(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy)	returns a cursor over the resultset.

Example of android SQLite database

Let's see the simple example of android sqlite database.

File: Contact.java

Now, let's create the database handler class that extends SQLiteOpenHelper class and provides the implementation of its methods.

package example.javatpoint.com.sqlitetutorial;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import java.util.ArrayList;import java.util.List;public class DatabaseHandler extends SQLiteOpenHelper { private static final int DATABASE_VERSION = 1; private static final String DATABASE_NAME = 'contactsManager'; private static final String TABLE_CONTACTS = 'contacts'; private static final String KEY_ID = 'id'; private static final String KEY_NAME = 'name'; private static final String KEY_PH_NO = 'phone_number'; public DatabaseHandler(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); //3rd argument to be passed is CursorFactory instance } // Creating Tables @Override public void onCreate(SQLiteDatabase db) { String CREATE_CONTACTS_TABLE = 'CREATE TABLE ' + TABLE_CONTACTS + '(' + KEY_ID + ' INTEGER PRIMARY KEY,' + KEY_NAME + ' TEXT,' + KEY_PH_NO + ' TEXT' + ')'; db.execSQL(CREATE_CONTACTS_TABLE); } // Upgrading database @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // Drop older table if existed db.execSQL('DROP TABLE IF EXISTS ' + TABLE_CONTACTS); // Create tables again onCreate(db); } // code to add the new contact void addContact(Contact contact) { SQLiteDatabase db = this.getWritableDatabase(); ContentValues values = new ContentValues(); values.put(KEY_NAME, contact.getName()); // Contact Name values.put(KEY_PH_NO, contact.getPhoneNumber()); // Contact Phone // Inserting Row db.insert(TABLE_CONTACTS, null, values); //2nd argument is String containing nullColumnHack db.close(); // Closing database connection } // code to get the single contact Contact getContact(int id) { SQLiteDatabase db = this.getReadableDatabase(); Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID, KEY_NAME, KEY_PH_NO }, KEY_ID + '=?', new String[] { String.valueOf(id) }, null, null, null, null); if (cursor != null) cursor.moveToFirst(); Contact contact = new Contact(Integer.parseInt(cursor.getString(0)), cursor.getString(1), cursor.getString(2)); // return contact return contact; } // code to get all contacts in a list view public List<Contact> getAllContacts() { List<Contact> contactList = new ArrayList<Contact>(); // Select All Query String selectQuery = 'SELECT * FROM ' + TABLE_CONTACTS; SQLiteDatabase db = this.getWritableDatabase(); Cursor cursor = db.rawQuery(selectQuery, null); // looping through all rows and adding to list if (cursor.moveToFirst()) { do { Contact contact = new Contact(); contact.setID(Integer.parseInt(cursor.getString(0))); contact.setName(cursor.getString(1)); contact.setPhoneNumber(cursor.getString(2)); // Adding contact to list contactList.add(contact); } while (cursor.moveToNext()); } // return contact list return contactList; } // code to update the single contact public int updateContact(Contact contact) { SQLiteDatabase db = this.getWritableDatabase(); ContentValues values = new ContentValues(); values.put(KEY_NAME, contact.getName()); values.put(KEY_PH_NO, contact.getPhoneNumber()); // updating row return db.update(TABLE_CONTACTS, values, KEY_ID + ' = ?', new String[] { String.valueOf(contact.getID()) }); } // Deleting single contact public void deleteContact(Contact contact) { SQLiteDatabase db = this.getWritableDatabase(); db.delete(TABLE_CONTACTS, KEY_ID + ' = ?', new String[] { String.valueOf(contact.getID()) }); db.close(); } // Getting contacts Count public int getContactsCount() { String countQuery = 'SELECT * FROM ' + TABLE_CONTACTS; SQLiteDatabase db = this.getReadableDatabase(); Cursor cursor = db.rawQuery(countQuery, null); cursor.close(); // return count return cursor.getCount(); }}

Output:

How to view the data stored in sqlite in android studio?

Follow the following steps to view the database and its data stored in android sqlite:

Open File Explorer.
Go to data directory inside data directory.
Search for your application package name.
Inside your application package go to databases where you will found your database (contactsManager).
Save your database (contactsManager) anywhere you like.
Download any SqLite browser plugins or tool (in my case DB Browser for SQLite).
Launch DB Browser for SQLite and open your database (contactsManager).
Go to Browse Data -> select your table (contacts) you will see the data stored.