Create Android SQLite database

最新推荐文章于 2021-09-22 11:16:24 发布

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#Android SQLite datab #create SQLite databa #SQLite database #android

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本文介绍如何在Android应用中创建和使用SQLite数据库。通过继承SQLiteOpenHelper类并重写onCreate方法来建立数据库及表结构。文章还展示了如何通过实例化自定义的SQLiteOpenHelper子类进行读写操作。

Android provides full support for SQLite databases.Any databases you create will be accessible by name to anyclass in the application, but not outside the application.

The recommended method to create a new SQLite database is to create a subclass ofSQLiteOpenHelper and override theonCreate() method, in which youcan execute a SQLite command to create tables in the database.

For example:

public class MyDb extends SQLiteOpenHelper {

    public static final String DB_NAME = "student_score.db";//数据库名
    public static final String TABLE_NAME = "student_score";//表名
    public static final String NAME = "name";//表中第二列 学生姓名
    public static final String SCORE = "score";//表中第三列 学生成绩

    public MyDb(Context context) {
        super(context, DB_NAME, null, 1);// 1 为数据库的版本
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        //创建表
        String sql = "create table " + TABLE_NAME + " (_id integer primary key autoincrement," +
                NAME + " text," +
                SCORE + " text" + ")";
        db.execSQL(sql);
    }

    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {}
}

You can then get an instance of your SQLiteOpenHelperimplementation using the constructor you've defined. To write to and read from the database, call getWritableDatabase() and getReadableDatabase(), respectively. These both return a SQLiteDatabase object that represents the database andprovides methods for SQLite operations.

MyDb myDb = new MyDb(context);
SQLiteDatabase readableDatabase = myDb.getReadableDatabase();

Run the application, I found the database file in the databases directory inside application package.

Open the database file is as follows.

SQLite数据库使用SQL命令增删改查