Insert, Read, Delete & Update Operation In SQLite.List Of All Clauses In SQLite For Defining Specific Condition.Introduction To SQLite And Installation.
Get Better Understanding of Sqlite Before You Read Example – To get better understanding of SQlite database, it is recommended you read below article first: If we have requirement that we don’t want to lose existing data in the table then we can write alter table query in the onUpgrade(SQLiteDatabase db,int oldVersion, int newVersion) method.įor more details read: Insert, Read, Delete & Update Operation In SQLite We have to change database version if we have added a new row in the database table. But it’s not mandatory to do so and it all depends upon your requirements. In most example you will see that existing table(s) are being dropped and again onCreate() method is being called to create tables again. In onUpgrade method we can write queries to perform whatever action is required. So to update a version we have to increment the value of version variable passed in the superclass constructor. OnUpgrade(SQLiteDatabase db,int oldVersion, int newVersion) is only called whenever there is a updation in existing version.
Database name is passed in constructor call. 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.
0 kommentar(er)
