![]() Add following code in MainAcitvity class package `in`.eyehunt. Now add following widget in activity_main.xml OR: From DatabaseUtils use method queryNumEntries(SQLiteDatabase db, String table). The method from Cursor to count size (number of rows in cursor) is, getCount() Returns the numbers of rows in the cursor. Its an always good practice you define your string in res/values/strings.xml. Using SELECT COUNT() FROM tablename query and, than count the size of Cursor. Add Button, TextView, EditText widget in MainActivity resource layout.īefore adding, you must add a string in the resource. SQLiteOpenHelper(context, DB_NAME, null, DB_VERSIOM) Step 3. Import Ĭlass DatabaseHandler(context: Context) : You may also want to implement the onDowngrade() or onOpen() methods, but they are not required in this example. Must override the onCreate() and onUpgrade() callback methods. } Step 2. Create DatabaseHandler kotlin class and extend SQLiteOpenHelper Package import import import import import import import 1. Create an android project in the android studio (Follow this tutorial: Android First Program in Android Studio kotlin) Step 2. Create a model class (POJO): UsersĬreate a package directory in the root package its good practice to maintain your code. 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. I am trying to create the database using SQLite. Most relational databases (Oracle, SQL Server and MySQL being prime. Completely null values are not allowed by the nullColumnHack. I creating a database application on AndroidStudio using Kotlin for a University project. SQLite is an embedded, relational database management system (RDBMS). 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 Kotlin for Android Monetization with Play Extend by device Build apps that give your users seamless experiences from phones to tablets, watches, and more. 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. What I want to do for import is to just delete the. Export is just a matter of storing a copy of the raw current.db file. To create an object that can create, open and manage the database, and to also specify the error handler. I am trying to implement a simple SQLite export/import for backup purposes. ![]() 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. However, according to another stackoverflow thread, if I want to compile to Kotlin/Native, I cannot use any Java file. For saving of data I would like to use a database like SQLite. Minimize the amount of data read from the database, because excess data retrieval can impact performance. For a multi-platform project, I consider Kotlin/Native, with the hope to have a common code base at least for business logic and saving of data. The functionality to use the SQLite database is provided by the class which is used for database creation and version management. To achieve faster performance, follow these performance principles: Read fewer rows and columns: Optimize your queries to retrieve only the necessary data. ![]()
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