Android SQLite表不存在

Question

I am trying to create and insert rows in an SQLite table. However, I get an error when inserting the rows that the table does not exist. Can anyone tell me what I am doing wrong here? Thanks!

The code in the activity that is calling the class to create the database and insert rows is as follows:

    // Open database
    db = new DBAdapter(this);
    db.open();

    // TODO: insertRecept statements hieronder verwijderen
    // Dienen enkel voor test om inhoud te hebben
    long id = db.insertRecept("aardappelen - bloemkool - kotelet");
    id = db.insertRecept("rijst - wokgroenten - scampi - currysaus");
    id = db.insertRecept("nasi goreng - omelet");
    id = db.insertRecept("ebly - veggieburger - provencaalse saus");
    id = db.insertRecept("rijst - kipfilet - zoetzure saus");
    id = db.insertRecept("ebly - veggieburger - provencaalse saus");
    id = db.insertRecept("puree - fish-sticks - spinazie");
    id = db.insertRecept("tortellini - kaassaus");
    id = db.insertRecept("aardappelen - bloemkool - chippolata");
    id = db.insertRecept("pizza");
    id = db.insertRecept("frietjes");
    id = db.insertRecept("aardappel - zalm - prei - melksaus");
    db.close();

The DBAdapter class is as follows:

package be.bertcarremans.weekmenu;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.DatabaseUtils;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

import java.sql.SQLException;

public class DBAdapter {
static final String KEY_ROWID = "_id";
static final String KEY_RECEPT_TITEL = "recept_titel";
static final String TAG = "DBAdapter";

static final String DATABASE_NAME = "recepten_db";
static final String DATABASE_TABLE = "recepten";
static final int DATABASE_VERSION = 1;

static final String DATABASE_CREATE =
        "CREATE TABLE recepten (_id INTEGER PRIMARY KEY AUTOINCREMENT, "
        + "recept_titel  TEXT NOT NULL);";

DatabaseHelper DBHelper;
SQLiteDatabase db;

final Context context;

// Constructor
public DBAdapter(Context ctx) {
    this.context = ctx;
    DBHelper = new DatabaseHelper(context);
}

private static class DatabaseHelper extends SQLiteOpenHelper {
    DatabaseHelper(Context context) {
        super(context,DATABASE_NAME,null,DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(DATABASE_CREATE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS recepten");
    }
}

// database openen
public DBAdapter open() {
    db = DBHelper.getWritableDatabase();
    return this;
}

// database sluiten
public void close() {
    DBHelper.close();
}

// recept toevoegen
public long insertRecept(String recept) {
    ContentValues initialValues = new ContentValues();
    initialValues.put(KEY_RECEPT_TITEL, recept);
    return db.insert(DATABASE_TABLE, null, initialValues);
}
}

Answer 1

It looks you most likely have changed the schema structure, and (most likely) bumped version number of your database. This, in conjunction with broken onUpgrade() implementation caused your problems.

As a quick solution: uninstall the app and install again - this will completely wipe the database and make your app create it on 1st run. But as a long term solution, you need to fix onUpgrade() . Right now you do this:

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS recepten");
}

so in human language it reads: "when we need to upgrade, just wipe the table". What about re-creating it after that? If you won't do that, you got no table. If you got no plans to have update code, then I'd move my table removal/creation code to (respectively) ie createTables() / removeTables() methods and just make my onUpgrade() use it:

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    removeTables(db);
    createTables(db);
}