数据库的创建及使用方法

1.数据库的创建
public class MyHelper extends SQLiteOpenHelper {
public MyHelper( Context context) {
super(context, “itcast.db”, null, 2);
public void onCreate(SQLiteDatabase db) {
db.execSQL(“CREATE TABLE information( id NTEGER PRIMARY
KEY AUTOINCREMENT, name VARCHAR(20), price INTEGER)”);
}
//当数据库的版本号增加时调用
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
2.添加数据方法
public void insert(String name,String price) {
SQLiteDatabase db = helper. getWritableDatabase();
ContentValues values = new ContentValues();
values.put(“name”, name);
values.put(" price", price);
long id = db.insert(“information” ,null,values);
db.close();
}
3·删除数据方法
public int delete(long id){
SQLiteDatabase db = helper. getWritableDatabase();
int number = db.delete(“information”, “_ id=?”, new String[] {id’+"});
db.close();
return number;
}
4查询数据方法
public boolean find(long id){
sQLiteDatabase db = helper.getR eadableDatabase();
Cursor cursor = db.query(“information”, null, “_ id=?”, new
String[]{id+"}, null, null, null);
boolean result = cursor.moveToNext（）;
close();
db.close(;
retuin result;
}
5.修改数据方法
public int update(String name, String price) {
SQLiteDatabase db = helper.get WritableDatabase(;
ContentValues values = new ContentValues(;
values.put(“price”, price);
int number = db.update(“information”, values, " name =?", new
String[] {name});
db.close();
return number;

本文地址：https://blog.csdn.net/qq_46372637/article/details/107163587