So SQLiteOpenHelper class call the onCreate() method after creating database and instantiate SQLiteDatabase object. It will be called whenever there is a first call to getReadableDatabase() or getWritableDatabase() function available in super SQLiteOpenHelper class. OnCreate(SQLiteDatabase sqLiteDatabase)method is called only once throughout the application lifecycle. After extending SQLiteOpenHelper you will need to implement its methods onCreate, onUpgrade and constructor. The SQLiteOpenHelper only require the DATABASE_NAME to create database. The SQLiteOpenHelper is responsible for opening database if exist, creating database if it does not exists and upgrading if required. It provides two methods onCreate(SQLiteDatabase db), onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion). SQLiteOpenHelper is a helper class to manage database creation and version management. 3 Add & Retrieve Image From SQLite Database:Ĭreating And Updating Database In Androidįor creating, updating and other operations you need to create a subclass or SQLiteOpenHelper class.1 Creating And Updating Database In Android. ![]() Package import import import import import import import java.util. The data stored can be checked on the logcat. In the below example, we are demonstrating the usage of the android SQLite database to store and fetch the data. Int update(String table, ContentValues values, String whereClause, String whereArgs)Ĭursor query(String table, String columns, String selection, String selectionArgs, String groupBy, String having, String orderBy) The values to be stored are specified by the third argument. The null values are stored by android, if the second argument is null and the values are empty. Completely null values are not allowed by the nullColumnHack. The table name is specified by the table. Long insert(String table, String nullColumnHack, ContentValues values) To execute the sql query not select query. Some of the important methods of the SQLiteDatabase class are: Method The SQLiteDatabase class has many methods. The methods like create, update, delete, select, etc, that are performed on the SQLite database are included in the SQLiteDatabase class. To be called when the database needs to be downgraded. ![]() Public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) To be called when the database needs to be upgraded. Public abstract void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) To be called when the database is created for the first time. Public abstract void onCreate(SQLiteDatabase db) Some of the important methods of the SQLiteOpenHelper class are: Method The SQLiteOpenHelper class has many methods. ![]() To create an object that can create, open and manage the database, and to also specify the error handler. SQLiteOpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version, DatabaseErrorHandler errorHandler) To create an object that can create, open and manage the database. SQLiteOpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) The SQLiteOpenHelper class has two constructors. The implementation of onCreate() and onUpgrade() methods of SQLiteOpenHelper class is required to be provided to perform any database operation. The functionality to use the SQLite database is provided by the class which is used for database creation and version management.
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