Android学习-每日打卡APP-进展

今天课比较多，但是还是要抽出时间写安卓，又有了一些小进展，将数据库的部分代码写了出来

可以参考一下

package com.example.clockappliction;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import androidx.annotation.Nullable;

public class DB extends SQLiteOpenHelper {
    private static final int DATABASE_VERSION=4;

    private static final String DATABASE_NAME="crud.db";

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

    @Override
    public void onCreate(SQLiteDatabase db) {

        String CREATE_TABLE_USER="CREATE TABLE " + Student.TABLE +"("
                +Student.KEYWORD+" INTEGER PRIMARY KEY AUTOINCREMENT ,"
                +Student.ID+" TEXT ,"
                +Student.NAME+" TEXT ,"
                +Student.GRADE+" TEXT ,"
                +Student.PHONE+" TEXT)";

        String CREATE_TABLE_CLOCK="CREATE TABLE " + Clock.TABLE +"("
                +Clock.KEYWORD+" INTEGER PRIMARY KEY AUTOINCREMENT ,"
                +Clock.DATE+" TEXT ,"
                +Clock.WORD+" TEXT ,"
                +Clock.SUMMARY+" TEXT ,"
                +Clock.MAXDAY+" TEXT)";
    }

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

        db.execSQL("DROP TABLE IF EXISTS "+ Student.TABLE);
        db.execSQL("DROP TABLE IF EXISTS "+ Clock.TABLE);
        onCreate(db);
    }
}