SQLiteOpenHelper数据库的创建or升级or增删改查，附项目源码

以下是一个简单的使用SQLiteOpenHelper来创建、升级、增删改查数据库的例子：

public class DatabaseHelper extends SQLiteOpenHelper {
 
    // 数据库名称
    private static final String DATABASE_NAME = "mydatabase.db";
    // 数据库版本
    private static final int DATABASE_VERSION = 1;
 
    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }
 
    @Override
    public void onCreate(SQLiteDatabase db) {
        // 创建表
        String CREATE_TABLE = "CREATE TABLE " + "mytable" + "("
                + "ID" + " INTEGER PRIMARY KEY AUTOINCREMENT," + "NAME" + " TEXT,"
                + "AGE" + " INTEGER" + ")";
        db.execSQL(CREATE_TABLE);
    }
 
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // 更新数据库
        db.execSQL("DROP TABLE IF EXISTS " + "mytable");
        onCreate(db);
    }
 
    // 增加记录
    public boolean insertData(String name, int age) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues cv = new ContentValues();
        cv.put("NAME", name);
        cv.put("AGE", age);
        long result = db.insert("mytable", null, cv);
        return result != -1;
    }
 
    // 删除记录
    public boolean deleteData(int id) {
        SQLiteDatabase db = this.getWritableDatabase();
        int result = db.delete("mytable", "ID = ?", new String[] { Integer.toString(id) });
        return result > 0;
    }
 
    // 更新记录
    public boolean updateData(int id, String name, int age) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues cv = new ContentValues();
        cv.put("NAME", name);
        cv.put("AGE", age);
        int result = db.update("mytable", cv, "ID = ?", new String[] { Integer.toString(id) });
        return result > 0;
    }
 
    // 查询记录
    public Cursor getData(int id) {
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.query("mytable", new String[] { "ID", "NAME", "AGE" }, "ID = ?", new String[] { Integer.toString(id) }, null, null, null);
        return cursor;
    }
}

使用方法：

DatabaseHelper dbHelper = new DatabaseHelper(context);
 
// 插入数据
dbHelper.insertData("John", 25);
 
// 删除数据
dbHelper.deleteData(1);
 
// 更新数据
dbHelper.updateData(1, "Jane", 30);
 
// 查询数据
Cursor cursor = dbHelper.getData(1);
if (cursor.moveToFirst()) {
    do {
        String name =