根据Android Studio编译器,数据库表不存在
我收到此错误:
android.database.sqlite.SQLiteException:否这样的表:设置(代码1):,而编译时:SELECT * FROM设置
但是我已经在DatabaseHandler文件中创建了表:
public class DatabaseHandler extends SQLiteOpenHelper { // Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "database.db";
//table name
private static final String TABLE_DETAILS = "details";
private static final String TABLE_FOOD = "food";
private static final String TABLE_OLDDETAILS = "oldDetails";
private static final String TABLE_SETTING = "setting";
//Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_HEIGHT = "height";
private static final String KEY_WEIGHT = "weight";
private static final String KEY_CALORIES = "calories";
private static final String KEY_DATE = "date";
private static final String KEY_LEVEL = "level";
private static final String KEY_DURATION = "duration";
private static final String KEY_DAYS = "days";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_DETAILS_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_DETAILS + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_HEIGHT + " REAL," + KEY_WEIGHT + " REAL " + ")";
String CREATE_FOOD_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_FOOD + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT," + KEY_CALORIES + " INTEGER " + ")";
String CREATE_OLDDETAILS_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_OLDDETAILS + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_DATE + " TEXT," + KEY_HEIGHT + " REAL," + KEY_WEIGHT + " REAL " + ")";
String CREATE_SETTING_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_SETTING + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_LEVEL + " INTEGER," + KEY_DURATION + " INTEGER," + KEY_DAYS + " INTEGER " + ")";
db.execSQL(CREATE_OLDDETAILS_TABLE);
db.execSQL(CREATE_DETAILS_TABLE);
db.execSQL(CREATE_FOOD_TABLE);
db.execSQL(CREATE_SETTING_TABLE);
}
// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_DETAILS);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_OLDDETAILS);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_FOOD);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_SETTING);
// Create tables again
onCreate(db);
}
public boolean addSetting(int level, int duration, int days) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ID, 1);
values.put(KEY_LEVEL, level);
values.put(KEY_DURATION, duration);
values.put(KEY_DAYS, days);
// Inserting Row
long result = db.insert(TABLE_SETTING, null, values);
if(result == -1){
return false;
}
else{
return true;
}
}
public boolean checkSetting(){
SQLiteDatabase db = this.getWritableDatabase();
String selectQuery = "SELECT * FROM " + TABLE_SETTING;
Cursor cursor = db.rawQuery(selectQuery, null);
Boolean rowExists;
if (cursor.moveToFirst())
{
// DO SOMETHING WITH CURSOR
rowExists = true;
} else
{
// I AM EMPTY
rowExists = false;
}
return rowExists;
}
public setting getSetting() {
String selectQuery = "SELECT * FROM " + TABLE_SETTING;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor != null)
cursor.moveToFirst();
setting set = new setting(cursor.getInt(1), cursor.getInt(2), cursor.getInt(3));
return set;
}
public int updateSetting(setting set) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_LEVEL, set.getLevel());
values.put(KEY_DURATION, set.getDuration());
values.put(KEY_DAYS, set.getDays());
Log.d("UPDATE: ", "updated all");
// updating row
return db.update(TABLE_SETTING, values, KEY_ID + " = ?", new String[] { String.valueOf(1) });
}
如您所见,虽然错误是重复发生的,但有一种“创建不存在的创建”方法,尽管此错误在我身上,但我正在尝试创建。
我正在尝试在一个片段中执行此数据库代码,您可以在此处看到它,到目前为止,似乎不是问题,我认为主要是DatabaseHandler。
如何SETTING
正确创建表格,以便可以从中进行选择?
回答:
您已经在安装应用程序时更改了数据库结构,但是onCreate
仅执行一次,因此您有两个选择可以使更改反映到数据库中
1.)将数据库版本递增一以执行onUpgrade
以将更改应用于现有数据库
2.)从手机上手动卸载该应用以执行 onCreate
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