Sqlite database tutorial androidstudio4/27/2024 ![]() does not exist in the folder)Īs part of error investigation I subsequently included code in the app which logs the file names that are present in the Files.DirAssets prior to the error occurring and the database file appears in the log - (see attached log). Researching the error (in B4X forums and google) it seems the most likely explanation for the error is that the database cannot be found (i.e. When I attempt to initialize the database the app fails with a SQL Error " : unknown error (code 1294 SQLITE_CANTOPEN_ENOENT): Could not open database" The app fails on line 45 of the included code I included the db in the files folder and according to information from various forum posts it should get installed in the Files.DirAssets folder when deployed to the phone (experimenting with including a db with the app) SQLiteDatabase.I have a simple app which includes a small SQLite database. The code of this constructor looks like this: public MyDBHandler(Context context, Stringname, The database can be initialized in the constructor of the MyDBHandler class. We must also use import statements, as follows: import Type Student in the Name item, maintain the default options, and click the OK button:Īdding the following lines of code for the Student class: public class Student Right-click the myfirstdatabase package and selecting New > Java Class. The Student class contains fields, constructors, and properties as follows: My application model can be shown in the following figure: A third class (Student class) will need to be implemented to hold the database entry data as it is passed between the activity and the handler. The database handler will be a subclass of SQLiteOpenHelper and will provide an abstract layer between the underlying SQLite database and the activity class. ![]() The application will consist of an activity and a database handler class (MyDBHandler class). We will create a database Android application that has a UI as follows: getReadableDatabase(): creates or opens a database for reading only.ĬontentValues allows key/value pairs to be declared consisting of table column identifiers and the values to be stored in each column.getWritableDatabase(): opens or creates a database for reading and writing.onOpen(): called when the database is opened.onUpgrade(): called in the event that the application code contains a more recent database version number reference.onCreate(): called when the database is created for the first time.SQLiteOpenHelper is designed to make it easier to create and update databases. rawQuery(): executes an SQL query statement and returns matching results in the form of a Cursor object.execSQL(): executes a single SQL Statement that does not return result data.query(): performs a specified database query and returns matching results via a Cursor object.delete(): deletes rows from a database table.insert(): inserts a new row into a database table.SQLiteDatabase provides the primary interface between the application code and underlying SQLite database. get() (such as getInt(), getDouble(), so on): returns the value of the specified contained at the specified column index of the row at the current cursor position. ![]() move(): moves by a specified offset from the current position in the result set.moveToNext(): moves to the next row in the result set.moveToLast(): moves to the last row in the result set.moveToFirst(): moves to the first row in the result set.getCount(): returns the number of rows contained within the result set. ![]()
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