How to delete all records from table in sqlite with Android?

In Android systems, to delete all records from an SQLite database table, you can execute a SQL DELETE statement. Here is a step-by-step guide with examples to help you understand how to perform this operation:

Step 1: Open or Create Database

First, ensure you have a working database instance, typically implemented using the SQLiteOpenHelper class. For example:

java
public class DatabaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "example.db";
    private static final int DATABASE_VERSION = 1;

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE IF NOT EXISTS records (_id INTEGER PRIMARY KEY, name TEXT)");
    }

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

Step 2: Delete All Records from the Table

Once the database is ready, you can execute a DELETE statement using the SQLiteDatabase instance to remove all records:

java
public void deleteAllRecords() {
    SQLiteDatabase db = this.getWritableDatabase();
    db.execSQL("DELETE FROM records");
}

In this example, we directly use the execSQL method to execute a SQL command that clears the records table. This will delete all data from the table while preserving the table structure.

Step 3: Close the Database

After completing the operation, remember to close the database resources:

java
db.close();

Remarks:

• Using DELETE FROM tableName; deletes all records from the table but does not reset the auto-increment field (if present). To reset the auto-increment field (e.g., _id), you can use DELETE followed by VACUUM, or delete and recreate the table.
• In actual development, ensure proper exception handling and atomicity when operating on the database to prevent data errors or loss.