Explain how to create and use databases in SQLite for Android applications

Introduction

SQLite is a relational database that is serverless, self-contained, and mostly ACID-comforming; it can store structured data in an android device. It’s among the Android OS goodies baked in ready to save and retrieve data offline.

Explanation

Android SQLite operates with the help of SQLiteOpenHelper, a class that handles database creation and version updating. Devs write tables, put stuff in them, edit and delete those entries with SQL queries.

To use SQLite in Android, generally the process goes like this:

Create a class extending SQLiteOpenHelper

Override onCreate() to create tables.

Overrride onUpgrade() and manage upgrades.

Code some of the SQL necessary to build tables.

Example:

CREATE TABLE students(id INTEGER PRIAMRY KEY AUTOINCREMENT, name TEXT, marks INTEGER);

Use CRUD operations

Create – Insert values

Read – Select records

Update – Modify records

Delete – Remove records

Access the database

Use getWritableDatabase() or getReadableDatabase().

Features / Characteristics

• Small and quick for local storage dumbass.
• No external server is required
• Uses standard SQL syntax
• Supports ACID transactions (Atomicity, Consistency, Isolation, Durability)
• Stores data in a single. db file

Great for off-line applications such as note-pad, digital calculator and student record

Example

• Simple SQLiteOpenHelper Class Example

public class DBHelper extends SQLiteOpenHelper {

public DBHelper(Context context) {
    super(context, "StudentDB", null, 1);
}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE students(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, marks INTEGER)");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS students");
    onCreate(db);
}

}

Insert Data Example:

SQLiteDatabase db = helper. getWritableDatabase(); ContentValues cv = new ContentValues(); cv. put(“name”, “Charan”); cv. put(“marks”, 90); db. insert(“students”, null, cv);

Advantages / Importance

• Provides efficient local storage
• No need for internet connectivity
• Fully supported by Android framework
• Better performance than external databases
• Quick backup and restore of all data
• Suitable for medium-sized structured datasets

Conclusion

SQLite is a powerful local database that comes pre-installed with Android which offers the capacity to store, manage and manipulate structured data. Its easy installation process along with the ability to work offline and supporting SQL also make it a perfect fit for mobile apps in need of an organized data structure.